Acknowledgement Note: This project was carried out as part of the “Carreras con Impacto” program during the mentorship phase. You can find more information about the program in this entry.
Note. Given the extensive nature of this text, it is suggested that the reader refer to section “1. Context of the Problem” to gain a comprehensive understanding of the overall framework of the research. Additionally, it is recommended to review section “3.3 Feasibility of Incorporating the Foods Obtained in Matrix III into Emergency Food Responses” in order to become familiar with the results obtained from the evaluation conducted. Furthermore, it is advisable to read sections “4. Conclusions” and “5. Future Perspectives” to identify relevant topics that may contribute to the enrichment of the field of study.
Abstract
This article addresses the importance of developing resilient food systems in response to potential Abrupt Sunlight Reduction Scenarios (ASRS). It initially focuses on identifying vitamin D-rich foods that can be produced, stored, and distributed during global food crises. Through the use of weighting matrices, various factors were evaluated, such as availability, vitamin D concentration, bioavailability, overall nutritional value, and production scalability. The results identify anchovies, chicken eggs, and cod liver oil as the most viable options to ensure adequate vitamin D intake. In particular, eggs and cod liver oil are effective during the first 3 to 9 months of the crisis, while anchovies are viable both during this initial period and the second phase, which lasts from 4 to 18 months. The study also analyzes the limitations and potential challenges in producing and distributing these foods under extreme conditions, highlighting the need for future research to propose strategies aimed at ensuring food security in crisis situations.
Keywords: Global Catastrophic Risk, Abrupt Sunlight Reduction Scenario, Resilient Foods, Vitamin D.
Sources of Information
The information used to develop this project comes from web pages, scientific articles and reviews where relevant characteristics of the foods selected for the project are detailed.
Motivations
Research on resilient foods has focused on those that can meet the minimum protein and carbohydrate requirements to prevent short-term health problems in the global population. However, it is also crucial to develop research on resilient foods that provide micronutrients, such as vitamin D, to prevent long-term medical problems in the event of a food crisis caused by an ASRS.
Objectives
General
Compare foods containing vitamin D based on key criteria to determine their potential for implementation in Abrupt Sunlight Reduction Scenarios (ASRS).
Specific
Identify foods containing vitamin D that can be effectively produced, stored, and distributed under extreme conditions.
Evaluate the bioavailability, vitamin D concentration, and general nutritional value of the selected foods.
Analyze the scalability of the production of these foods, considering factors such as cost, adaptability to different environments, shelf life, and technological requirements.
Determine the portions and combinations of foods necessary to meet the daily vitamin D requirements for different age groups during an ASRS.
1. Context of the Problem
A global catastrophic risk is an event capable of causing irreparable damage worldwide, threatening human survival. An example of such a catastrophe would be an event causing 10 million deaths or economic losses amounting to 10 billion dollars, such as a pandemic. Even if some regions of the world remained unaffected, the widespread impact would classify such an event as a global catastrophe [1].
An Abrupt Sunlight Reduction Scenario (ASRS) is another example, triggered by natural phenomena like asteroid impacts or supervolcanic eruptions, or by human activities such as nuclear war[2]. In an ASRS caused by a nuclear winter, it is estimated that 75% of the current world population could die from famine if swift and effective action is not taken[3].
During an ASRS, the dispersion of particles in the atmosphere blocks solar radiation, leading to a significant reduction in sunlight reaching the Earth’s surface[4]. This phenomenon can trigger drastic changes in the global climate, suddenly reducing sunlight, temperatures, and precipitation, thus affecting agricultural production and endangering global food security[5].
For this reason, it is essential to prepare current production systems to ensure their adaptation in similar situations, which, although less likely than other global catastrophic risks[6], still pose a threat to human life.
In anticipation of potential large-scale catastrophes, the scientific community has focused its efforts on identifying foods that could ensure population survival under extreme conditions[7]. Resilient foods offer a viable solution to ensure the production, storage, and distribution of nutritious foods, even under adverse circumstances[8]. To prevent mass famines, malnutrition, and public health issues, research has been conducted to develop resilient diets that humanity could adopt in global crisis scenarios[3]. Until now, research in this field has mainly focused on selecting foods that meet the caloric and protein requirements necessary to ensure short-term population survival[9]. However, the importance of micronutrients, such as vitamin D, has been underestimated, even though they could become extremely scarce in a global ASRS[3]. The lack of specific studies addressing how these foods could be produced, stored, and distributed in global crisis scenarios limits effective preparedness for such eventualities.
Vitamin D is essential for calcium absorption and immune system function; its deficiency can cause osteoporosis, muscle weakness, and increase the risk of autoimmune diseases[10]. Ensuring adequate intake of vitamin D is crucial to prevent various long-term medical conditions.
Several studies have identified a variety of foods containing vitamin D that could serve as essential sources of this nutrient in low-sunlight situations. These foods include certain fatty fish[3][11], fish oils[12], fortified milk[13], algae[14], beef liver[15], chicken eggs[16], and some natural or UV-exposed mushrooms[17]. However, criteria such as availability, production scalability, bioavailability, and the general nutritional value of these foods vary considerably, making it necessary to evaluate which ones are best suited for inclusion in resilient diets during an ASR.
This project aims to contribute to this field by evaluating, based on specific criteria, different foods containing vitamin D to determine their viability and potential for implementation in food crises caused by an ASR. In doing so, the project not only seeks to identify the most effective sources of vitamin D but also to establish the basis for promoting research and strategies aimed at ensuring the health and survival of the population under extreme conditions.
2. Methodology
The type of research employed is descriptive-evaluative, based on information obtained from secondary sources, including both qualitative and quantitative data.
The information was evaluated using weighted matrices, a tool commonly used to select and prioritize ideas based on predefined criteria.
2.1 Matrix of Foods that Provide Vitamin D
The first weighted matrix was developed in several stages. Initially, a literature review was conducted to select 11 foods with vitamin D content from various sources:
Fungi: natural oyster mushrooms and UV-enriched shiitake mushrooms.
Plant: seaweed.
Most of these foods were selected based on the mention of their vitamin D content in the article by Pham et al. (2022)[3]. However, other foods, such as anchovy, cod liver oil, fortified milk, chicken eggs, beef liver, and seaweed, were chosen because various bibliographic sources indicated they have a considerable amount of this vitamin.
Next, the evaluation criteria for the weighted matrix were identified and selected. The evaluation of each food based on these criteria was carried out according to the type of data available for each. The selected criteria are: Distribution of Production, Vitamin D Concentration, Bioavailability, and General Nutritional Value.
Among all the criteria, Bioavailability was the only one for which qualitative data were assigned numerical values, allowing for this information to be quantified in the matrix. The other criteria were evaluated using a different approach: a maximum possible value was established for each, and scores were calculated for foods that achieved lower results.
It is important to note that, with the goal of selecting the most beneficial foods in terms of vitamin D, higher scores were assigned to the Bioavailability and Vitamin D Concentration criteria.
Distribution of Production (20 points): Evaluates the global availability of foods, considering the number of continents leading their production[18].
Vitamin D Concentration (µg vitamin D/100g of food) (30 points): Quantifies the amount of vitamin D present in the food.
Bioavailability (30 points): Measures the body’s ability to absorb and utilize the vitamin D present in the food[19].
High (30 points): If the food contains D3 and additional components that positively contribute to its absorption.
Medium (15 points): If the food contains D3 or D2 and requires the consumption of additional foods to enhance its absorption.
Low (7.5 points): If individuals have difficulty absorbing vitamin D through this food.
General Nutritional Value (20 points): Considers the overall nutritional profile of the food, including the content of other macronutrients and additional micronutrients.
2.2 Matrix of Production Scalability
Matrix I offers a general evaluation that considers diverse criteria essential in assessing the foods selected for the project. Matrix II, on the other hand, focuses specifically on production scalability, which is one of the criteria that will be incorporated later into Matrix I. This approach was adopted because specific sub-criteria were used to evaluate the scalability of production for the foods that scored highest in Matrix I.
In Matrix II, foods that scored above 60 were selected to narrow the scope of the research and apply a second weighted matrix to determine their production scalability based on five criteria: Sales Cost, Food Adaptability to Different Environments, Maximum Shelf Life, and Infrastructure and Technology Requirements.
The criteria for Sales Cost, Maximum Shelf Life, and Seasonal Production were evaluated using a quantitative analysis. Meanwhile, the criteria for Food Adaptability to Different Environments and Infrastructure and Technology required the quantification of qualitative data, which was then integrated into the overall evaluation.
It is worth noting that due to the prioritization of criteria in this study, less weight was assigned to the criterion of seasonal production.
This is because, in the context of a food crisis caused by a global catastrophe, seasonality could be a less decisive factor compared to the other criteria.
Sales Cost (USD/kg) (5 points): Total value of all direct and indirect expenses associated with the production or acquisition of a product, from its origin to its readiness for sale[20].
Food Adaptability to Different Environments (5 points): The ability of the food to grow in diverse climates and under extreme conditions[21].
High (5 points): The food can grow and develop in a wide variety of climates.
Medium (2.5 points): The food can be obtained in several regions but requires specific conditions for its growth.
Low (1.75 points): The food grows in very specific conditions and cannot easily adapt to other climates.
Maximum Shelf Life of the Food (months) (5 points): Evaluates the ability of a food to remain in optimal consumption conditions for an extended period[22].
Infrastructure and Technology (5 points): Refers to the tools and technologies required for the food’s production.
Low (5 points): No advanced infrastructure or cutting-edge technology is required for its production and processing.
Medium (2.5 points): Traditional infrastructure and technology are required for its production and processing.
High (1.75 points): Advanced infrastructure and cutting-edge technology are required for its production and processing.
Seasonality of Production (2 points): Evaluates the availability of the food throughout the year. It is classified based on whether the food can be produced and is available year-round, or if its production is limited to certain times of the year due to climatic, biological, or market factors[23].
Finally, the weighted values of Matrix I were adjusted to integrate the value of the Production Scalability criterion obtained in Matrix II. This was applied to the seven foods selected in the first stage of the project to conduct a comprehensive evaluation of the five chosen criteria. This resulted in the final outcomes, determining which foods scored the highest based on the proposed evaluation.
Distribution of Production (17 points)
Vitamin D Concentration (µg vitamin D/100g of food) (22 points)
Bioavailability (22 points)
General Nutritional Value (17 points)
Production Scalability (22 points)
3. Results and Discussion
3.1 Evaluation of Preselected Criteria
Table 1. Weighted Matrix I – Foods Providing Vitamin D
Note: A = Distibution of Production, B = Vitamin D Concentration (µg vitamin D/100g), C = Bioavailability, D = General Nutritional Value
The results obtained in Table 1 show that mushrooms scored low compared to other foods evaluated, mainly due to their low natural vitamin D content[17]. However, it is noteworthy that when enriched with UV-B radiation, the vitamin D content in mushrooms can significantly increase: by 98.10% in the case of shiitake mushrooms and by 97.77% in the case of oyster mushrooms. While there is evidence that experimental treatments adjusting factors such as UV-B irradiation, temperature, and exposure time can further increase vitamin D content[24], this technology is currently more common in countries like the United States, Ireland, the Netherlands, and Australia[17], limiting its global application and, therefore, its widespread distribution.
In terms of bioavailability, it is important to highlight that mushrooms contain a provitamin called ergosterol, which converts to vitamin D2 when exposed to ultraviolet light. However, vitamin D2 degrades more rapidly in the body and has a shorter duration compared to vitamin D3, leading to less efficient absorption in the human body[25].
A similar situation occurs with seaweed. It has been reported that Sargassum muticum, also known as Japanese sargassum, has significant potential to produce vitamin D[26]. However, current records of vitamin D2 content in these algae are low compared to other foods, limiting their absorption in the human body due to both the amount and form in which the vitamin is found.
On the other hand, fortified cow’s milk is highlighted as a widely available food around the world[27]. However, due to its low levels of vitamin D[28] and fats that could improve the body’s ability to absorb vitamin D3, it is not considered a high-potential food for providing this vitamin in food crisis situations.
For these reasons, along with obtaining a score below 60 in the selection matrix, UV-enriched mushrooms, unenriched mushrooms, fortified cow’s milk, and seaweed were excluded from consideration in the next stage of the Production Scalability evaluation (Table 2).
Of the seven foods selected for evaluation in the Production Scalability Matrix, all come from animal sources, with fish being predominant. These foods are distinguished by their significant content of vitamin D3, high nutritional value in essential macronutrients, and their ability to facilitate the metabolization of this vitamin in the human body. It is noteworthy that some foods scored high in the matrix due to their general nutritional value and extended production, rather than their vitamin D content, such as chicken eggs and beef liver.
Regarding cod liver oil, which received the highest score in the evaluation, it is noted that although its distribution is not as extensive and it does not contain a high concentration of other essential macronutrients and micronutrients, it is the food with the highest vitamin D content compared to the others evaluated. Additionally, it contains additional components that improve the absorption of this vitamin in the human body, making it an important source of vitamin D, despite its limitations in terms of availability and general nutritional balance.
3.2 Evaluation of Production Scalability
This criterion evaluates the ability to scale the production of a specific food to meet the nutritional demands required by the population.
Table 2. Weighted Matrix II – Production Scalability
Note: A = Sales Cost (USD/Kg), B = Adaptability to Different Environments, C = Maximum Shelf Life (months), D = Infrastructure and Technology Requirements, E = Seasonality of Production.
Cod Liver Oil
The evaluation indicates that the most expensive food among those evaluated is cod liver oil, which is priced on the market at around $124 USD. This product is obtained through a traditional process that includes steam cooking, mechanical pressing, filtration, and other steps to extract the oil[29]. The multiple unit processes explain why it scored low in the Infrastructure and Technology criterion, as specialized equipment and careful handling are required, driving up production costs.
Cod is primarily found in the North Atlantic and Arctic Oceans[30], especially in cold waters of regions such as Norway, Iceland, and Canada[31]. The specific climatic conditions necessary for its habitat limit its availability, meaning that it cannot be easily accessed by the global population throughout the year. In fact, it has been reported that cod fishing is viable for only about 9 months of the year[32], further limiting its availability.
This seasonality, combined with growing demand due to the awareness of its nutritional benefits, has led to a rise in price.
Additionally, cod liver oil is commonly marketed as a nutritional supplement in the form of capsules and bottled oil. These products have a maximum shelf life of 24 months if properly stored in cool, dry conditions[33]. The need for specific preservation and storage processes to maintain the quality of the oil also contributes to its high cost and limited accessibility.
Fatty Fish
Among the fish evaluated, the most expensive on the market are salmon and mackerel. These fish are priced higher due to factors such as their global culinary popularity, the high demand for their nutritional benefits, and the costs associated with their farming and capture. Salmon, for example, is valued for its high content of omega-3 fatty acids and high-quality protein, which increases its demand and, consequently, its price[34].
In general, once fish are caught, they do not require advanced tools or technology for processing. Traditional processing methods, such as filleting, canning, and freezing, are relatively simple and do not demand sophisticated equipment[35]. This technological accessibility and lower need for specialized infrastructure allow for a more economical and adaptable production process, reflected in a high score in this criterion.
Among the four fish analyzed (anchovy, mackerel, salmon, and sardine), only sardine presents significant limitations in terms of adaptation to different environments.
Sardines require cool temperatures and nutrient-rich waters to reproduce[36], which restricts their geographic distribution. On the other hand, the other three fish show greater adaptability. For example, mackerel has been recorded to thrive in non-conventional waters, demonstrating its resilience and ability to develop in various regions.
Regarding preservation, during an Abrupt Sunlight Reduction Scenario (ASRS), this aspect would become crucial, as environmental conditions could change drastically, affecting agricultural production and the availability of fresh food. The selected fatty fish, having similar characteristics in composition, exhibit similar preservation times when frozen. This method, though limited in time, is more economical and simpler than other alternatives[22].
Specifically, mackerel, sardines, and salmon have a maximum shelf life of 3 months when frozen[37]. Anchovies, however, can be preserved for up to 6 months under freezing conditions, attributed to their lower fat content compared to the other fish, which reduces the risk of oxidation and spoilage[38].
In terms of seasonality of production, anchovy, mackerel, and sardine are available during different seasons, with approximately 6 months of capture per year[39]. Salmon, on the other hand, has slightly less availability, with about 5 months of capture per year. These seasonal variations affect the availability and cost of these fish, making seasonality a key factor in assessing their potential as a source of vitamin D during food crises.
Chicken Eggs
Eggs stand out as one of the most economical foods evaluated. According to Global Product Prices[40], the average global cost of 1 kg of eggs (approximately 17.2 units) is $4.59 USD. This affordability is due to their wide availability in much of the world and massive annual production, exceeding 80 million tons[41]. However, eggs require specific storage conditions, limiting their adaptability to different environments and resulting in a short preservation time.
Despite these challenges, eggs do not require advanced technology or infrastructure for production. Furthermore, their production takes place throughout the year[42], contributing to a high score in the seasonality of production criterion.
Beef Liver
Beef liver requires storage in cold conditions, between 0°C and 3°C or 7°C [43], to extend its preservation for subsequent consumption, classifying it as having low adaptability in terms of preservation. When frozen, its maximum shelf life is relatively short, approximately 3.5 months.
The extraction and processing of beef liver are carried out in slaughterhouses, which are equipped with the necessary infrastructure for the slaughter, processing, and refrigeration of the meat. Processing liver does not require advanced technology, as it only needs to be cleaned, cut, and packaged using common equipment in the meat industry[44]. Similarly, preservation through freezing or vacuum packaging is done using traditional methods, classifying this process at a low level in terms of infrastructure and technology.
In terms of seasonality, beef liver is available year-round globally, as its production is not subject to the seasonal restrictions affecting some agricultural products. Countries with a strong livestock industry, such as the United States, Brazil, and China, are capable of producing beef continuously[45], ensuring a constant supply in global markets throughout the year.
3.3 Final Evaluation
Below is Matrix I (Table 3) with the Production Scalability criterion included, along with the corresponding scores for each food.
Table 3. Weighted Matrix III – Final Evaluation
Note: A = Distribution of Production, B = Vitamin D Concentration (µg vD/100g), C = Bioavailability, D = General Nutritional Value, E = Production Scalability.
By incorporating the Production Scalability criterion into Matrix I, it is highlighted that the food with the highest score is anchovy. Chicken eggs and cod liver oil also received favorable scores, ranking second and third, respectively.
It is important to note that anchovy achieved a higher score than eggs and cod liver oil in this third matrix due to its performance in the Production Scalability criterion (Matrix II), where the other two foods did not score as highly and were even surpassed by the other three evaluated fish.
By achieving the highest score in the evaluation, anchovy stands out as the most suitable resilient food to address vitamin D deficiency during a food crisis, excelling in most of the assessed criteria. In contrast, the other two foods with favorable results (chicken eggs and cod liver oil) excel in specific criteria. Eggs are notable for their widespread global distribution, high bioavailability, and strong overall nutritional value. On the other hand, cod liver oil is recognized for having the highest vitamin D content among the foods evaluated, as well as its high bioavailability.
3.4 Feasibility of Incorporating the Foods Obtained in Matrix III into Emergency Food Responses
In the study by Pham et al. (2022)[3], it is proposed that an extreme Abrupt Sunlight Reduction Scenario (ASRS), caused by the injection of 150 Tg of soot into the troposphere and stratosphere during a nuclear war, would generate a global food crisis of massive magnitude. In such a situation, it is emphasized that priority should be given to resilient foods that can be produced under drastically reduced temperature and precipitation conditions, in order to meet essential nutritional needs for human survival.
Anchovy
One of the foods proposed in the research by Allfed is anchovy, emphasizing its prolonged availability as the most fished species worldwide[3], with catches reaching 8.4 million tons in 2013. Anchovy is an important source of protein, omega-3 fatty acids, sodium, selenium, phosphorus, iron, niacin, vitamin D, and vitamin B12[46]. It is estimated that there would be availability of anchovy fishing during the first year after the catastrophe, although volumes may decrease over time due to reduced food sources for anchovy, a consequence of lower photosynthetic capacity in low-sunlight scenarios.
Anchovy presents itself as a viable food option to implement during both the initial and sustained phases of an ASRS, although it could become a limited resource between 9 to 18 months following a large-scale catastrophic event[3].
Chicken Eggs
Chicken eggs stand out for their high production volumes, widespread global distribution, and affordable prices. They are also a source of high-quality protein and contain all the essential amino acids required by the human body[47]. However, due to the low adaptability of eggs to different environments and their limited shelf life through freezing[48], it is anticipated that their availability to the population will decrease over time in the event of a global ASRS.
An ASRS would have devastating effects on egg production. The reduction of photosynthesis, caused by the decreased solar radiation, would lead to a sharp drop in agricultural yields[2].
This would directly affect the feeding of laying hens, as the main crops used in their diet, such as corn and soybeans, are highly dependent on sunlight for growth[49]. Additionally, the lack of adequate nutrients in the hens’ diet could weaken their immune systems and reduce their egg-laying capacity [50].
For these reasons, there may be a limited supply of eggs available in the initial months following the catastrophe. This is because current production systems have some capacity to store feed for the birds and can maintain normal production for a short period.
However, after a few months, the feed reserves would begin to run out, and farms would be unable to replenish supplies at the same rate. At that point, egg production would begin to decrease significantly due to the lack of feed for the hens. In this scenario, egg prices would rise sharply, and access to them would become more limited.
Cod Liver Oil
As mentioned earlier, cod liver oil is the food with the highest vitamin D content among those evaluated. However, based on the evaluation of project criteria, it was recognized that it is also the most expensive food evaluated, lacks widespread geographical distribution, and requires specific climatic conditions for its availability. For these reasons, some factors could contribute to its scarcity during an ASRS:
Marine Ecosystem: Changes in water temperature and the marine food chain could affect cod populations, reducing their availability for fishing[51]. Increased Demand: The need for essential nutrients, such as vitamin D[3], could lead to increased demand for cod liver oil, depleting reserves more quickly.
Supply Chain Disruptions: Logistical problems, fuel shortages, and restrictions on fishing could limit the production and distribution of cod liver oil[52].
In an ASRS, cod liver oil may initially be available during the first few months following the catastrophe. However, its scarcity would become more pronounced as existing reserves are depleted and conditions for fishing and distribution become increasingly adverse.
Nevertheless, it is worth noting that due to the preservation properties of cod liver oil, which has a shelf life of up to 24 months[33], it would be possible to store its production and use it to meet nutritional needs in the months following the catastrophe. This would be particularly valuable in a scenario where other foods may begin to run out, providing a source of essential nutrients such as vitamin D and omega-3 fatty acids over an extended period. This long-term storage capability could significantly contribute to food security in crisis situations.
3.5 Food Portions to Meet Vitamin D Requirements Based on Age
According to the recommendations from the National Institutes of Health[53], the optimal daily intake of vitamin D is classified by age groups, as shown in Table 4.
Table 4. Daily Recommended Doses of Vitamin D by NIH
In this sense, it is possible to establish the portions of foods that people of different ages need to consume to meet their vitamin D requirements, considering the availability of the foods that obtained the highest scores in the evaluation.
Table 5. Recommended Consumption Portions by Age and Periods
Note: Each period is expected to last between 3 and 9 months[3]. PA = Anchovy, HG = Chicken Eggs, AHB = Cod Liver Oil.
In Table 5, it is shown that the availability of anchovy would occur in the first two periods after the catastrophe, which would allow people to consume this food in “normal” portions to meet their vitamin D needs during these periods. In contrast, the situation is different for chicken eggs, which contain a relatively low amount of vitamin D (1.57 µg/100g). To meet vitamin D requirements through eggs, several units would need to be consumed, which may not be practical or safe due to the association of high egg consumption with cardiovascular effects[54].
For individuals aged 1 to 70 years, as well as pregnant or breastfeeding women, it is suggested not to consume more than 14 eggs per week[55]. This recommendation suggests that the maximum amount of eggs recommended for human consumption is two eggs per day, to avoid potential adverse effects from other compounds in eggs. When consuming two eggs daily, it would be necessary to complement the diet with an additional food source to meet vitamin D requirements; such individuals could supplement their diet with anchovy or other fish rich in this vitamin.
Similarly to eggs, cod liver oil is estimated to be available only during the first period post-catastrophe, unless its long shelf life is utilized for consumption in later periods.
Additionally, the use of multivitamin supplements is recommended. These products, available in capsule or oil form, contain not only vitamin D but also a variety of other essential vitamins and minerals.
It is crucial to follow the consumption instructions specified on the supplement’s label, which generally advises not to exceed the recommended daily doses[56]. For example, it is suggested not to consume more than 5 ml in the case of liquid oil or one capsule per day for capsule-format supplements, to avoid unwanted effects associated with an excess of vitamins and minerals.
In this context, it is not recommended to consume multiple capsules or exceed the recommended milliliters of oil. Instead, it is preferable to combine the use of multivitamin supplements with naturally vitamin D-rich foods, such as anchovy or other fatty fish, to meet the daily vitamin D requirements safely and effectively.
3.6 Other Foods That Can Provide Vitamin D
There are other types of foods that can provide vitamin D in food crisis contexts and were not included in the analysis. Below are a few examples:
Lanolin
This is a natural fat extracted from sheep’s wool, obtained through a washing process that separates the lanolin from the raw wool. This process involves washing the wool with detergents to release the fat, which is then purified and processed to obtain refined lanolin.
Lanolin is a common source of vitamin D3 in supplements, as it contains precursors of vitamin D that, when irradiated with ultraviolet light, are transformed into vitamin D3. While lanolin is not consumed directly as a food, it is used to fortify other food products
with vitamin D, such as dairy products, margarine, and cereals, thus contributing to meeting daily vitamin D needs[57].
Enriched Yeast
This type of yeast is treated with ultraviolet light to increase its content of vitamin D2, making it a viable source of this vitamin, especially for vegan diets. It can be used in the preparation of bread and other baked goods, making it a practical option in situations of scarcity. Although it is a relatively “new” product, the European Food Safety Authority (2014) issued a report indicating that, while subject to some restrictions, it is safe for consumption[58].
Lichens
Lichens are a symbiosis between fungi and algae and represent a natural source of vitamin D[59]. Lichens are particularly valuable in regions where other sources of vitamin D are limited or inaccessible, such as in Nordic countries. In these regions, the regular consumption of reindeer meat, which feeds on the lichen Cladonia rangiferina (rich in vitamin D), helps residents meet their vitamin D requirements.
Similar to lanolin, lichens are used in the manufacture of vitamin D supplements, available in different forms such as capsules or liquid drops.
These foods were not selected for evaluation using the project’s criteria, as it was difficult to find data in the literature regarding the current production volume and distribution as well as other information needed to assess their scalability based on the selected sub-criteria.
For this reason, they were not included in the evaluation; however, future research is recommended to evaluate their potential use in food crisis situations.
3.7 Project Limitations
During the selection of the evaluation criteria for Matrix I, it was considered essential to include bioavailability. This criterion is crucial to defining and understanding the capacity of each food to enable the distribution and utilization of vitamin D in the body’s internal processes. However, no records were found in the literature measuring the bioavailability of the foods selected for the project. For this reason, a qualitative evaluation of this criterion was opted for, considering how vitamin D is presented in the foods and whether these foods contain additional components that may enhance its absorption.
Due to time constraints, an analysis was not conducted on all the foods evaluated in Matrix I. Evaluating the scalability of production criterion for all the foods would have enriched the project results, as the benefits and drawbacks of a broader variety of foods could have been considered. This would have allowed for identifying whether there were foods that could be produced during Periods II and III and how they could be consumed across different stages of life.
The project prioritized the study of “wild-caught” fish over farmed fish. While aquaculture could be a viable strategy to ensure food production during an Abrupt Sunlight Reduction Scenario (ASRS) in a food crisis, fully adapting the system to fish farming would require considerable use of various resources, which would likely be limited during a large-scale global catastrophe. Furthermore, studies have shown that wild-caught fatty fish contain higher levels of vitamin D and other nutrients compared to farmed fish (Lu et al., 2007; Jakobsen et al., 2019). Therefore, it was considered that wild-caught fish could have a greater implementation impact in a food crisis situation where vitamin D deficiency is present in the population.
For these reasons, it is suggested to investigate the current capacity of fish farms to assess whether this system could extend food availability in a prolonged scarcity scenario.
4. Conclusions
Anchovy, chicken eggs, and cod liver oil emerged as the most viable options to ensure adequate vitamin D intake during food crises. Anchovy was identified as the most suitable food due to its high vitamin D concentration, bioavailability, and production scalability.
Although chicken eggs and cod liver oil also proved to be important sources of vitamin D, they present limitations regarding their adaptability to different environments and long-term preservation. Additionally, the availability of these foods could be compromised by adverse climatic factors and the seasonality of production.
The research highlights the need for future studies to evaluate other potential foods, such as lanolin, products made from enriched yeast, and lichens, which, although not included in the analysis due to lack of data, could offer additional solutions in food crisis scenarios.
It is recommended to develop food strategies that integrate vitamin D-rich foods to mitigate deficiencies and ensure the population’s health during an ASRS. Moreover, it is essential to consider the costs, necessary infrastructure, and production scalability of these foods to optimize their availability and accessibility during a global food crisis.
5. Future Perspectives
This project serves as only an initial step in identifying foods that could be used during an ASRS to meet the daily vitamin D requirements. However, there is significant room for further research in this field. To enhance this line of study, it is recommended to explore a broader range of foods that could be utilized in such situations and to consider additional criteria. These criteria include analyzing the current production volume of these foods, the complexity of their production processes, and the role of industries involved in their production. Furthermore, it is crucial to assess the production capacity of these resilient foods in different regions of the world, taking into account geographical, economic, and technological factors that could affect their global availability and accessibility.
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Exploration of Foods High in Vitamin D as a Dietary Strategy in the Event of Abrupt Sunlight Reduction
By: Juliana María Álvarez García
Acknowledgement Note:
This project was carried out as part of the “Carreras con Impacto” program during the mentorship phase. You can find more information about the program in this entry.
Note. Given the extensive nature of this text, it is suggested that the reader refer to section “1. Context of the Problem” to gain a comprehensive understanding of the overall framework of the research. Additionally, it is recommended to review section “3.3 Feasibility of Incorporating the Foods Obtained in Matrix III into Emergency Food Responses” in order to become familiar with the results obtained from the evaluation conducted. Furthermore, it is advisable to read sections “4. Conclusions” and “5. Future Perspectives” to identify relevant topics that may contribute to the enrichment of the field of study.
Abstract
This article addresses the importance of developing resilient food systems in response to potential Abrupt Sunlight Reduction Scenarios (ASRS). It initially focuses on identifying vitamin D-rich foods that can be produced, stored, and distributed during global food crises. Through the use of weighting matrices, various factors were evaluated, such as availability, vitamin D concentration, bioavailability, overall nutritional value, and production scalability. The results identify anchovies, chicken eggs, and cod liver oil as the most viable options to ensure adequate vitamin D intake. In particular, eggs and cod liver oil are effective during the first 3 to 9 months of the crisis, while anchovies are viable both during this initial period and the second phase, which lasts from 4 to 18 months. The study also analyzes the limitations and potential challenges in producing and distributing these foods under extreme conditions, highlighting the need for future research to propose strategies aimed at ensuring food security in crisis situations.
Keywords: Global Catastrophic Risk, Abrupt Sunlight Reduction Scenario, Resilient Foods, Vitamin D.
Sources of Information
The information used to develop this project comes from web pages, scientific articles and reviews where relevant characteristics of the foods selected for the project are detailed.
Motivations
Research on resilient foods has focused on those that can meet the minimum protein and carbohydrate requirements to prevent short-term health problems in the global population. However, it is also crucial to develop research on resilient foods that provide micronutrients, such as vitamin D, to prevent long-term medical problems in the event of a food crisis caused by an ASRS.
Objectives
General
Compare foods containing vitamin D based on key criteria to determine their potential for implementation in Abrupt Sunlight Reduction Scenarios (ASRS).
Specific
Identify foods containing vitamin D that can be effectively produced, stored, and distributed under extreme conditions.
Evaluate the bioavailability, vitamin D concentration, and general nutritional value of the selected foods.
Analyze the scalability of the production of these foods, considering factors such as cost, adaptability to different environments, shelf life, and technological requirements.
Determine the portions and combinations of foods necessary to meet the daily vitamin D requirements for different age groups during an ASRS.
1. Context of the Problem
A global catastrophic risk is an event capable of causing irreparable damage worldwide, threatening human survival. An example of such a catastrophe would be an event causing 10 million deaths or economic losses amounting to 10 billion dollars, such as a pandemic. Even if some regions of the world remained unaffected, the widespread impact would classify such an event as a global catastrophe [1].
An Abrupt Sunlight Reduction Scenario (ASRS) is another example, triggered by natural phenomena like asteroid impacts or supervolcanic eruptions, or by human activities such as nuclear war[2]. In an ASRS caused by a nuclear winter, it is estimated that 75% of the current world population could die from famine if swift and effective action is not taken[3].
During an ASRS, the dispersion of particles in the atmosphere blocks solar radiation, leading to a significant reduction in sunlight reaching the Earth’s surface[4]. This phenomenon can trigger drastic changes in the global climate, suddenly reducing sunlight, temperatures, and precipitation, thus affecting agricultural production and endangering global food security[5].
For this reason, it is essential to prepare current production systems to ensure their adaptation in similar situations, which, although less likely than other global catastrophic risks[6], still pose a threat to human life.
In anticipation of potential large-scale catastrophes, the scientific community has focused its efforts on identifying foods that could ensure population survival under extreme conditions[7]. Resilient foods offer a viable solution to ensure the production, storage, and distribution of nutritious foods, even under adverse circumstances[8]. To prevent mass famines, malnutrition, and public health issues, research has been conducted to develop resilient diets that humanity could adopt in global crisis scenarios[3]. Until now, research in this field has mainly focused on selecting foods that meet the caloric and protein requirements necessary to ensure short-term population survival[9]. However, the importance of micronutrients, such as vitamin D, has been underestimated, even though they could become extremely scarce in a global ASRS[3]. The lack of specific studies addressing how these foods could be produced, stored, and distributed in global crisis scenarios limits effective preparedness for such eventualities.
Vitamin D is essential for calcium absorption and immune system function; its deficiency can cause osteoporosis, muscle weakness, and increase the risk of autoimmune diseases[10]. Ensuring adequate intake of vitamin D is crucial to prevent various long-term medical conditions.
Several studies have identified a variety of foods containing vitamin D that could serve as essential sources of this nutrient in low-sunlight situations. These foods include certain fatty fish[3][11], fish oils[12], fortified milk[13], algae[14], beef liver[15], chicken eggs[16], and some natural or UV-exposed mushrooms[17]. However, criteria such as availability, production scalability, bioavailability, and the general nutritional value of these foods vary considerably, making it necessary to evaluate which ones are best suited for inclusion in resilient diets during an ASR.
This project aims to contribute to this field by evaluating, based on specific criteria, different foods containing vitamin D to determine their viability and potential for implementation in food crises caused by an ASR. In doing so, the project not only seeks to identify the most effective sources of vitamin D but also to establish the basis for promoting research and strategies aimed at ensuring the health and survival of the population under extreme conditions.
2. Methodology
The type of research employed is descriptive-evaluative, based on information obtained from secondary sources, including both qualitative and quantitative data.
The information was evaluated using weighted matrices, a tool commonly used to select and prioritize ideas based on predefined criteria.
2.1 Matrix of Foods that Provide Vitamin D
The first weighted matrix was developed in several stages. Initially, a literature review was conducted to select 11 foods with vitamin D content from various sources:
Animal: anchovy, salmon, mackerel, sardine, cod liver oil, fortified milk, chicken eggs, and beef liver.
Fungi: natural oyster mushrooms and UV-enriched shiitake mushrooms.
Plant: seaweed.
Most of these foods were selected based on the mention of their vitamin D content in the article by Pham et al. (2022)[3]. However, other foods, such as anchovy, cod liver oil, fortified milk, chicken eggs, beef liver, and seaweed, were chosen because various bibliographic sources indicated they have a considerable amount of this vitamin.
Next, the evaluation criteria for the weighted matrix were identified and selected. The evaluation of each food based on these criteria was carried out according to the type of data available for each. The selected criteria are: Distribution of Production, Vitamin D Concentration, Bioavailability, and General Nutritional Value.
Among all the criteria, Bioavailability was the only one for which qualitative data were assigned numerical values, allowing for this information to be quantified in the matrix. The other criteria were evaluated using a different approach: a maximum possible value was established for each, and scores were calculated for foods that achieved lower results.
It is important to note that, with the goal of selecting the most beneficial foods in terms of vitamin D, higher scores were assigned to the Bioavailability and Vitamin D Concentration criteria.
Distribution of Production (20 points): Evaluates the global availability of foods, considering the number of continents leading their production[18].
Vitamin D Concentration (µg vitamin D/100g of food) (30 points): Quantifies the amount of vitamin D present in the food.
Bioavailability (30 points): Measures the body’s ability to absorb and utilize the vitamin D present in the food[19].
High (30 points): If the food contains D3 and additional components that positively contribute to its absorption.
Medium (15 points): If the food contains D3 or D2 and requires the consumption of additional foods to enhance its absorption.
Low (7.5 points): If individuals have difficulty absorbing vitamin D through this food.
General Nutritional Value (20 points): Considers the overall nutritional profile of the food, including the content of other macronutrients and additional micronutrients.
2.2 Matrix of Production Scalability
Matrix I offers a general evaluation that considers diverse criteria essential in assessing the foods selected for the project. Matrix II, on the other hand, focuses specifically on production scalability, which is one of the criteria that will be incorporated later into Matrix I. This approach was adopted because specific sub-criteria were used to evaluate the scalability of production for the foods that scored highest in Matrix I.
In Matrix II, foods that scored above 60 were selected to narrow the scope of the research and apply a second weighted matrix to determine their production scalability based on five criteria: Sales Cost, Food Adaptability to Different Environments, Maximum Shelf Life, and Infrastructure and Technology Requirements.
The criteria for Sales Cost, Maximum Shelf Life, and Seasonal Production were evaluated using a quantitative analysis. Meanwhile, the criteria for Food Adaptability to Different Environments and Infrastructure and Technology required the quantification of qualitative data, which was then integrated into the overall evaluation.
It is worth noting that due to the prioritization of criteria in this study, less weight was assigned to the criterion of seasonal production.
This is because, in the context of a food crisis caused by a global catastrophe, seasonality could be a less decisive factor compared to the other criteria.
Sales Cost (USD/kg) (5 points): Total value of all direct and indirect expenses associated with the production or acquisition of a product, from its origin to its readiness for sale[20].
Food Adaptability to Different Environments (5 points): The ability of the food to grow in diverse climates and under extreme conditions[21].
High (5 points): The food can grow and develop in a wide variety of climates.
Medium (2.5 points): The food can be obtained in several regions but requires specific conditions for its growth.
Low (1.75 points): The food grows in very specific conditions and cannot easily adapt to other climates.
Maximum Shelf Life of the Food (months) (5 points): Evaluates the ability of a food to remain in optimal consumption conditions for an extended period[22].
Infrastructure and Technology (5 points): Refers to the tools and technologies required for the food’s production.
Low (5 points): No advanced infrastructure or cutting-edge technology is required for its production and processing.
Medium (2.5 points): Traditional infrastructure and technology are required for its production and processing.
High (1.75 points): Advanced infrastructure and cutting-edge technology are required for its production and processing.
Seasonality of Production (2 points): Evaluates the availability of the food throughout the year. It is classified based on whether the food can be produced and is available year-round, or if its production is limited to certain times of the year due to climatic, biological, or market factors[23].
Finally, the weighted values of Matrix I were adjusted to integrate the value of the Production Scalability criterion obtained in Matrix II. This was applied to the seven foods selected in the first stage of the project to conduct a comprehensive evaluation of the five chosen criteria. This resulted in the final outcomes, determining which foods scored the highest based on the proposed evaluation.
Distribution of Production (17 points)
Vitamin D Concentration (µg vitamin D/100g of food) (22 points)
Bioavailability (22 points)
General Nutritional Value (17 points)
Production Scalability (22 points)
3. Results and Discussion
3.1 Evaluation of Preselected Criteria
Table 1. Weighted Matrix I – Foods Providing Vitamin D
Note: A = Distibution of Production, B = Vitamin D Concentration (µg vitamin D/100g), C = Bioavailability, D = General Nutritional Value
The results obtained in Table 1 show that mushrooms scored low compared to other foods evaluated, mainly due to their low natural vitamin D content[17]. However, it is noteworthy that when enriched with UV-B radiation, the vitamin D content in mushrooms can significantly increase: by 98.10% in the case of shiitake mushrooms and by 97.77% in the case of oyster mushrooms. While there is evidence that experimental treatments adjusting factors such as UV-B irradiation, temperature, and exposure time can further increase vitamin D content[24], this technology is currently more common in countries like the United States, Ireland, the Netherlands, and Australia[17], limiting its global application and, therefore, its widespread distribution.
In terms of bioavailability, it is important to highlight that mushrooms contain a provitamin called ergosterol, which converts to vitamin D2 when exposed to ultraviolet light. However, vitamin D2 degrades more rapidly in the body and has a shorter duration compared to vitamin D3, leading to less efficient absorption in the human body[25].
A similar situation occurs with seaweed. It has been reported that Sargassum muticum, also known as Japanese sargassum, has significant potential to produce vitamin D[26]. However, current records of vitamin D2 content in these algae are low compared to other foods, limiting their absorption in the human body due to both the amount and form in which the vitamin is found.
On the other hand, fortified cow’s milk is highlighted as a widely available food around the world[27]. However, due to its low levels of vitamin D[28] and fats that could improve the body’s ability to absorb vitamin D3, it is not considered a high-potential food for providing this vitamin in food crisis situations.
For these reasons, along with obtaining a score below 60 in the selection matrix, UV-enriched mushrooms, unenriched mushrooms, fortified cow’s milk, and seaweed were excluded from consideration in the next stage of the Production Scalability evaluation (Table 2).
Of the seven foods selected for evaluation in the Production Scalability Matrix, all come from animal sources, with fish being predominant. These foods are distinguished by their significant content of vitamin D3, high nutritional value in essential macronutrients, and their ability to facilitate the metabolization of this vitamin in the human body. It is noteworthy that some foods scored high in the matrix due to their general nutritional value and extended production, rather than their vitamin D content, such as chicken eggs and beef liver.
Regarding cod liver oil, which received the highest score in the evaluation, it is noted that although its distribution is not as extensive and it does not contain a high concentration of other essential macronutrients and micronutrients, it is the food with the highest vitamin D content compared to the others evaluated. Additionally, it contains additional components that improve the absorption of this vitamin in the human body, making it an important source of vitamin D, despite its limitations in terms of availability and general nutritional balance.
3.2 Evaluation of Production Scalability
This criterion evaluates the ability to scale the production of a specific food to meet the nutritional demands required by the population.
Table 2. Weighted Matrix II – Production Scalability
Note: A = Sales Cost (USD/Kg), B = Adaptability to Different Environments, C = Maximum Shelf Life (months), D = Infrastructure and Technology Requirements, E = Seasonality of Production.
Cod Liver Oil
The evaluation indicates that the most expensive food among those evaluated is cod liver oil, which is priced on the market at around $124 USD. This product is obtained through a traditional process that includes steam cooking, mechanical pressing, filtration, and other steps to extract the oil[29]. The multiple unit processes explain why it scored low in the Infrastructure and Technology criterion, as specialized equipment and careful handling are required, driving up production costs.
Cod is primarily found in the North Atlantic and Arctic Oceans[30], especially in cold waters of regions such as Norway, Iceland, and Canada[31]. The specific climatic conditions necessary for its habitat limit its availability, meaning that it cannot be easily accessed by the global population throughout the year. In fact, it has been reported that cod fishing is viable for only about 9 months of the year[32], further limiting its availability.
This seasonality, combined with growing demand due to the awareness of its nutritional benefits, has led to a rise in price.
Additionally, cod liver oil is commonly marketed as a nutritional supplement in the form of capsules and bottled oil. These products have a maximum shelf life of 24 months if properly stored in cool, dry conditions[33]. The need for specific preservation and storage processes to maintain the quality of the oil also contributes to its high cost and limited accessibility.
Fatty Fish
Among the fish evaluated, the most expensive on the market are salmon and mackerel. These fish are priced higher due to factors such as their global culinary popularity, the high demand for their nutritional benefits, and the costs associated with their farming and capture. Salmon, for example, is valued for its high content of omega-3 fatty acids and high-quality protein, which increases its demand and, consequently, its price[34].
In general, once fish are caught, they do not require advanced tools or technology for processing. Traditional processing methods, such as filleting, canning, and freezing, are relatively simple and do not demand sophisticated equipment[35]. This technological accessibility and lower need for specialized infrastructure allow for a more economical and adaptable production process, reflected in a high score in this criterion.
Among the four fish analyzed (anchovy, mackerel, salmon, and sardine), only sardine presents significant limitations in terms of adaptation to different environments.
Sardines require cool temperatures and nutrient-rich waters to reproduce[36], which restricts their geographic distribution. On the other hand, the other three fish show greater adaptability. For example, mackerel has been recorded to thrive in non-conventional waters, demonstrating its resilience and ability to develop in various regions.
Regarding preservation, during an Abrupt Sunlight Reduction Scenario (ASRS), this aspect would become crucial, as environmental conditions could change drastically, affecting agricultural production and the availability of fresh food. The selected fatty fish, having similar characteristics in composition, exhibit similar preservation times when frozen. This method, though limited in time, is more economical and simpler than other alternatives[22].
Specifically, mackerel, sardines, and salmon have a maximum shelf life of 3 months when frozen[37]. Anchovies, however, can be preserved for up to 6 months under freezing conditions, attributed to their lower fat content compared to the other fish, which reduces the risk of oxidation and spoilage[38].
In terms of seasonality of production, anchovy, mackerel, and sardine are available during different seasons, with approximately 6 months of capture per year[39]. Salmon, on the other hand, has slightly less availability, with about 5 months of capture per year. These seasonal variations affect the availability and cost of these fish, making seasonality a key factor in assessing their potential as a source of vitamin D during food crises.
Chicken Eggs
Eggs stand out as one of the most economical foods evaluated. According to Global Product Prices[40], the average global cost of 1 kg of eggs (approximately 17.2 units) is $4.59 USD. This affordability is due to their wide availability in much of the world and massive annual production, exceeding 80 million tons[41]. However, eggs require specific storage conditions, limiting their adaptability to different environments and resulting in a short preservation time.
Despite these challenges, eggs do not require advanced technology or infrastructure for production. Furthermore, their production takes place throughout the year[42], contributing to a high score in the seasonality of production criterion.
Beef Liver
Beef liver requires storage in cold conditions, between 0°C and 3°C or 7°C [43], to extend its preservation for subsequent consumption, classifying it as having low adaptability in terms of preservation. When frozen, its maximum shelf life is relatively short, approximately 3.5 months.
The extraction and processing of beef liver are carried out in slaughterhouses, which are equipped with the necessary infrastructure for the slaughter, processing, and refrigeration of the meat. Processing liver does not require advanced technology, as it only needs to be cleaned, cut, and packaged using common equipment in the meat industry[44]. Similarly, preservation through freezing or vacuum packaging is done using traditional methods, classifying this process at a low level in terms of infrastructure and technology.
In terms of seasonality, beef liver is available year-round globally, as its production is not subject to the seasonal restrictions affecting some agricultural products. Countries with a strong livestock industry, such as the United States, Brazil, and China, are capable of producing beef continuously[45], ensuring a constant supply in global markets throughout the year.
3.3 Final Evaluation
Below is Matrix I (Table 3) with the Production Scalability criterion included, along with the corresponding scores for each food.
Table 3. Weighted Matrix III – Final Evaluation
Note: A = Distribution of Production, B = Vitamin D Concentration (µg vD/100g), C = Bioavailability, D = General Nutritional Value, E = Production Scalability.
By incorporating the Production Scalability criterion into Matrix I, it is highlighted that the food with the highest score is anchovy. Chicken eggs and cod liver oil also received favorable scores, ranking second and third, respectively.
It is important to note that anchovy achieved a higher score than eggs and cod liver oil in this third matrix due to its performance in the Production Scalability criterion (Matrix II), where the other two foods did not score as highly and were even surpassed by the other three evaluated fish.
By achieving the highest score in the evaluation, anchovy stands out as the most suitable resilient food to address vitamin D deficiency during a food crisis, excelling in most of the assessed criteria. In contrast, the other two foods with favorable results (chicken eggs and cod liver oil) excel in specific criteria. Eggs are notable for their widespread global distribution, high bioavailability, and strong overall nutritional value. On the other hand, cod liver oil is recognized for having the highest vitamin D content among the foods evaluated, as well as its high bioavailability.
3.4 Feasibility of Incorporating the Foods Obtained in Matrix III into Emergency Food Responses
In the study by Pham et al. (2022)[3], it is proposed that an extreme Abrupt Sunlight Reduction Scenario (ASRS), caused by the injection of 150 Tg of soot into the troposphere and stratosphere during a nuclear war, would generate a global food crisis of massive magnitude. In such a situation, it is emphasized that priority should be given to resilient foods that can be produced under drastically reduced temperature and precipitation conditions, in order to meet essential nutritional needs for human survival.
Anchovy
One of the foods proposed in the research by Allfed is anchovy, emphasizing its prolonged availability as the most fished species worldwide[3], with catches reaching 8.4 million tons in 2013. Anchovy is an important source of protein, omega-3 fatty acids, sodium, selenium, phosphorus, iron, niacin, vitamin D, and vitamin B12[46]. It is estimated that there would be availability of anchovy fishing during the first year after the catastrophe, although volumes may decrease over time due to reduced food sources for anchovy, a consequence of lower photosynthetic capacity in low-sunlight scenarios.
Anchovy presents itself as a viable food option to implement during both the initial and sustained phases of an ASRS, although it could become a limited resource between 9 to 18 months following a large-scale catastrophic event[3].
Chicken Eggs
Chicken eggs stand out for their high production volumes, widespread global distribution, and affordable prices. They are also a source of high-quality protein and contain all the essential amino acids required by the human body[47]. However, due to the low adaptability of eggs to different environments and their limited shelf life through freezing[48], it is anticipated that their availability to the population will decrease over time in the event of a global ASRS.
An ASRS would have devastating effects on egg production. The reduction of photosynthesis, caused by the decreased solar radiation, would lead to a sharp drop in agricultural yields[2].
This would directly affect the feeding of laying hens, as the main crops used in their diet, such as corn and soybeans, are highly dependent on sunlight for growth[49]. Additionally, the lack of adequate nutrients in the hens’ diet could weaken their immune systems and reduce their egg-laying capacity [50].
For these reasons, there may be a limited supply of eggs available in the initial months following the catastrophe. This is because current production systems have some capacity to store feed for the birds and can maintain normal production for a short period.
However, after a few months, the feed reserves would begin to run out, and farms would be unable to replenish supplies at the same rate. At that point, egg production would begin to decrease significantly due to the lack of feed for the hens. In this scenario, egg prices would rise sharply, and access to them would become more limited.
Cod Liver Oil
As mentioned earlier, cod liver oil is the food with the highest vitamin D content among those evaluated. However, based on the evaluation of project criteria, it was recognized that it is also the most expensive food evaluated, lacks widespread geographical distribution, and requires specific climatic conditions for its availability. For these reasons, some factors could contribute to its scarcity during an ASRS:
Marine Ecosystem: Changes in water temperature and the marine food chain could affect cod populations, reducing their availability for fishing[51]. Increased Demand: The need for essential nutrients, such as vitamin D[3], could lead to increased demand for cod liver oil, depleting reserves more quickly.
Supply Chain Disruptions: Logistical problems, fuel shortages, and restrictions on fishing could limit the production and distribution of cod liver oil[52].
In an ASRS, cod liver oil may initially be available during the first few months following the catastrophe. However, its scarcity would become more pronounced as existing reserves are depleted and conditions for fishing and distribution become increasingly adverse.
Nevertheless, it is worth noting that due to the preservation properties of cod liver oil, which has a shelf life of up to 24 months[33], it would be possible to store its production and use it to meet nutritional needs in the months following the catastrophe. This would be particularly valuable in a scenario where other foods may begin to run out, providing a source of essential nutrients such as vitamin D and omega-3 fatty acids over an extended period. This long-term storage capability could significantly contribute to food security in crisis situations.
3.5 Food Portions to Meet Vitamin D Requirements Based on Age
According to the recommendations from the National Institutes of Health[53], the optimal daily intake of vitamin D is classified by age groups, as shown in Table 4.
Table 4. Daily Recommended Doses of Vitamin D by NIH
Note: Adapted from NIH (2024)[53].
In this sense, it is possible to establish the portions of foods that people of different ages need to consume to meet their vitamin D requirements, considering the availability of the foods that obtained the highest scores in the evaluation.
Table 5. Recommended Consumption Portions by Age and Periods
Note: Each period is expected to last between 3 and 9 months[3]. PA = Anchovy, HG = Chicken Eggs, AHB = Cod Liver Oil.
In Table 5, it is shown that the availability of anchovy would occur in the first two periods after the catastrophe, which would allow people to consume this food in “normal” portions to meet their vitamin D needs during these periods. In contrast, the situation is different for chicken eggs, which contain a relatively low amount of vitamin D (1.57 µg/100g). To meet vitamin D requirements through eggs, several units would need to be consumed, which may not be practical or safe due to the association of high egg consumption with cardiovascular effects[54].
For individuals aged 1 to 70 years, as well as pregnant or breastfeeding women, it is suggested not to consume more than 14 eggs per week[55]. This recommendation suggests that the maximum amount of eggs recommended for human consumption is two eggs per day, to avoid potential adverse effects from other compounds in eggs. When consuming two eggs daily, it would be necessary to complement the diet with an additional food source to meet vitamin D requirements; such individuals could supplement their diet with anchovy or other fish rich in this vitamin.
Similarly to eggs, cod liver oil is estimated to be available only during the first period post-catastrophe, unless its long shelf life is utilized for consumption in later periods.
Additionally, the use of multivitamin supplements is recommended. These products, available in capsule or oil form, contain not only vitamin D but also a variety of other essential vitamins and minerals.
It is crucial to follow the consumption instructions specified on the supplement’s label, which generally advises not to exceed the recommended daily doses[56]. For example, it is suggested not to consume more than 5 ml in the case of liquid oil or one capsule per day for capsule-format supplements, to avoid unwanted effects associated with an excess of vitamins and minerals.
In this context, it is not recommended to consume multiple capsules or exceed the recommended milliliters of oil. Instead, it is preferable to combine the use of multivitamin supplements with naturally vitamin D-rich foods, such as anchovy or other fatty fish, to meet the daily vitamin D requirements safely and effectively.
3.6 Other Foods That Can Provide Vitamin D
There are other types of foods that can provide vitamin D in food crisis contexts and were not included in the analysis. Below are a few examples:
Lanolin
This is a natural fat extracted from sheep’s wool, obtained through a washing process that separates the lanolin from the raw wool. This process involves washing the wool with detergents to release the fat, which is then purified and processed to obtain refined lanolin.
Lanolin is a common source of vitamin D3 in supplements, as it contains precursors of vitamin D that, when irradiated with ultraviolet light, are transformed into vitamin D3. While lanolin is not consumed directly as a food, it is used to fortify other food products
with vitamin D, such as dairy products, margarine, and cereals, thus contributing to meeting daily vitamin D needs[57].
Enriched Yeast
This type of yeast is treated with ultraviolet light to increase its content of vitamin D2, making it a viable source of this vitamin, especially for vegan diets. It can be used in the preparation of bread and other baked goods, making it a practical option in situations of scarcity. Although it is a relatively “new” product, the European Food Safety Authority (2014) issued a report indicating that, while subject to some restrictions, it is safe for consumption[58].
Lichens
Lichens are a symbiosis between fungi and algae and represent a natural source of vitamin D[59]. Lichens are particularly valuable in regions where other sources of vitamin D are limited or inaccessible, such as in Nordic countries. In these regions, the regular consumption of reindeer meat, which feeds on the lichen Cladonia rangiferina (rich in vitamin D), helps residents meet their vitamin D requirements.
Similar to lanolin, lichens are used in the manufacture of vitamin D supplements, available in different forms such as capsules or liquid drops.
These foods were not selected for evaluation using the project’s criteria, as it was difficult to find data in the literature regarding the current production volume and distribution as well as other information needed to assess their scalability based on the selected sub-criteria.
For this reason, they were not included in the evaluation; however, future research is recommended to evaluate their potential use in food crisis situations.
3.7 Project Limitations
During the selection of the evaluation criteria for Matrix I, it was considered essential to include bioavailability. This criterion is crucial to defining and understanding the capacity of each food to enable the distribution and utilization of vitamin D in the body’s internal processes. However, no records were found in the literature measuring the bioavailability of the foods selected for the project. For this reason, a qualitative evaluation of this criterion was opted for, considering how vitamin D is presented in the foods and whether these foods contain additional components that may enhance its absorption.
Due to time constraints, an analysis was not conducted on all the foods evaluated in Matrix I. Evaluating the scalability of production criterion for all the foods would have enriched the project results, as the benefits and drawbacks of a broader variety of foods could have been considered. This would have allowed for identifying whether there were foods that could be produced during Periods II and III and how they could be consumed across different stages of life.
The project prioritized the study of “wild-caught” fish over farmed fish. While aquaculture could be a viable strategy to ensure food production during an Abrupt Sunlight Reduction Scenario (ASRS) in a food crisis, fully adapting the system to fish farming would require considerable use of various resources, which would likely be limited during a large-scale global catastrophe. Furthermore, studies have shown that wild-caught fatty fish contain higher levels of vitamin D and other nutrients compared to farmed fish (Lu et al., 2007; Jakobsen et al., 2019). Therefore, it was considered that wild-caught fish could have a greater implementation impact in a food crisis situation where vitamin D deficiency is present in the population.
For these reasons, it is suggested to investigate the current capacity of fish farms to assess whether this system could extend food availability in a prolonged scarcity scenario.
4. Conclusions
Anchovy, chicken eggs, and cod liver oil emerged as the most viable options to ensure adequate vitamin D intake during food crises. Anchovy was identified as the most suitable food due to its high vitamin D concentration, bioavailability, and production scalability.
Although chicken eggs and cod liver oil also proved to be important sources of vitamin D, they present limitations regarding their adaptability to different environments and long-term preservation. Additionally, the availability of these foods could be compromised by adverse climatic factors and the seasonality of production.
The research highlights the need for future studies to evaluate other potential foods, such as lanolin, products made from enriched yeast, and lichens, which, although not included in the analysis due to lack of data, could offer additional solutions in food crisis scenarios.
It is recommended to develop food strategies that integrate vitamin D-rich foods to mitigate deficiencies and ensure the population’s health during an ASRS. Moreover, it is essential to consider the costs, necessary infrastructure, and production scalability of these foods to optimize their availability and accessibility during a global food crisis.
5. Future Perspectives
This project serves as only an initial step in identifying foods that could be used during an ASRS to meet the daily vitamin D requirements. However, there is significant room for further research in this field. To enhance this line of study, it is recommended to explore a broader range of foods that could be utilized in such situations and to consider additional criteria. These criteria include analyzing the current production volume of these foods, the complexity of their production processes, and the role of industries involved in their production. Furthermore, it is crucial to assess the production capacity of these resilient foods in different regions of the world, taking into account geographical, economic, and technological factors that could affect their global availability and accessibility.
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