Thanks for writing this! This is really interesting. I only skimmed, but my basic reaction is that I agree that hypertension is an important problem, but am skeptical about salt taxes as a solution. Here are a few reasons why:
1) I suspect salt taxes are less effective at reducing consumption of the offending agent than other kinds of sin taxes (e.g., sugar, tobacco) for two reasons. First, per the linked article, the taxes have historically been applied to salty foods, like chips, instant noodles, and salted nuts. But I suspect a large percentage of the salt people consume comes from the food they cook. Second, it is easier to replace the salt that is taken out of salty foods. You wouldn’t buy a sugar-free soda and add sugar to it, but you might well add salt to nuts, instant noodles, and so on. (My parents would buy unsalted microwave popcorn when I was a kid, and I developed workarounds...)
2) This is very speculative, but I worry that salt taxes—which, as you note, will be unpopular—could lead to broader backlash against sin taxes, in much the same way that more draconian masking rules have, perhaps, incited broader backlash against masking. It would be very bad if pushing for salt taxes led to reduced public support for tobacco taxes.
3) Like other commenters, I’m a bit skeptical of the extent to which reducing salt consumption reduces blood pressure. Just looking quickly at this Cochrane review, the drop in systolic blood pressure (SBP) for hypertensive people was 5mm Hg (and only 2mm Hg for normotensive people) with reduced salt consumption. These drops may be statistically significant, but I’m not bowled over by their clinical significance. If a patient with a BP of 150⁄90 reduced their SBP to 145 by limiting salt consumption, you’d put them on an antihypertensive.
4) I’m perhaps most confused by how quickly antihypertensives are dismissed as an option— ”medications, will by their nature be more expensive as an intervention than policy change.” My understanding is that the substantial reductions in cardiovascular mortality seen in the Western world are largely attributable to the use of antihypertensives and statins. Even in the US, you can get a 30-day supply of lisinopril for $3.75, and you’d expect this to reduce the above patient’s SBP by 17-23 mm Hg—a 3-4x greater reduction than you’d see with reduced salt consumption.
5) Of course, health care costs much more than just the cost of medications. But if you want a policy solution, I’m inclined to think that a better intervention would involve widespread population BP screening and incentivizing providers to prescribe (and patients to take) antihypertensives. Polypills—which include, e.g., antihypertensives, aspirin, and statins—also look really promising and do more than just reduce hypertension, although pharmaceutical companies have little incentive to make these. So I’d also be eager to see policy solutions aimed at making polypills more widely available.
“Public Health England has estimated that 85% of the salt people ingest is already in food at the point of purchase and consumers only add the other 15% during cooking or at the table.”
Anecdotally, people add less salt to the food they cook themselves than is added to processed foods in the factory. If this is true, even if people do ‘top up’ salt levels in their food, they will likely still end up with less salt.
Plus there’s salt in all sorts of crazy things like breakfast cereal. If that gets reduced, I don’t think people are going to start salting their fruit loops.
(1) My understanding is that literal packs/shakers of salt sold in supermarkets would not be exempt from the sodium tax. But that raises more dramatic political problems (e.g. at a $0.3 per mg tax, that increases a 500g packet of salt by 100x), and I presume the per mg tax on literal raw salt would have to be far lower. In general, I do agree that substitution with home food is a worry, though there will also be frictions (i.e. not perfect substitutes because of the social element, time needed to cook, etc).
(2) I’m not sure if this is a significant concern—it depends on your frame of reference, and one could easily argue the opposite (e.g. more aggressive sin taxes normalizes them/shifts the overton window, so even if the extreme version gets rejected, people see the more conventional ones like on tobacco and alcohol as reasonable by comparison). In general, I’m not sure if we have strong reason to believe one way or another.
(3) I think I’m fairly deferential to the scientific consensus in this area, which seems strong—it’s something I’ll definitely look more closely into via expert intervews.
(4) & (5) Generally, direct delivery (whether of medication or general checkups/treatments) is a lot more expensive due to (a) actually requiring ongoing resources, and (b) counterfactual costliness, for an EA charity. I agree that they could be promising, but in the context of a shallow review I made the call to focus on what seemed to be the most impactful solution—I could be wrong!
Thanks for writing this! This is really interesting. I only skimmed, but my basic reaction is that I agree that hypertension is an important problem, but am skeptical about salt taxes as a solution. Here are a few reasons why:
1) I suspect salt taxes are less effective at reducing consumption of the offending agent than other kinds of sin taxes (e.g., sugar, tobacco) for two reasons. First, per the linked article, the taxes have historically been applied to salty foods, like chips, instant noodles, and salted nuts. But I suspect a large percentage of the salt people consume comes from the food they cook. Second, it is easier to replace the salt that is taken out of salty foods. You wouldn’t buy a sugar-free soda and add sugar to it, but you might well add salt to nuts, instant noodles, and so on. (My parents would buy unsalted microwave popcorn when I was a kid, and I developed workarounds...)
2) This is very speculative, but I worry that salt taxes—which, as you note, will be unpopular—could lead to broader backlash against sin taxes, in much the same way that more draconian masking rules have, perhaps, incited broader backlash against masking. It would be very bad if pushing for salt taxes led to reduced public support for tobacco taxes.
3) Like other commenters, I’m a bit skeptical of the extent to which reducing salt consumption reduces blood pressure. Just looking quickly at this Cochrane review, the drop in systolic blood pressure (SBP) for hypertensive people was 5mm Hg (and only 2mm Hg for normotensive people) with reduced salt consumption. These drops may be statistically significant, but I’m not bowled over by their clinical significance. If a patient with a BP of 150⁄90 reduced their SBP to 145 by limiting salt consumption, you’d put them on an antihypertensive.
4) I’m perhaps most confused by how quickly antihypertensives are dismissed as an option—
”medications, will by their nature be more expensive as an intervention than policy change.” My understanding is that the substantial reductions in cardiovascular mortality seen in the Western world are largely attributable to the use of antihypertensives and statins. Even in the US, you can get a 30-day supply of lisinopril for $3.75, and you’d expect this to reduce the above patient’s SBP by 17-23 mm Hg—a 3-4x greater reduction than you’d see with reduced salt consumption.
5) Of course, health care costs much more than just the cost of medications. But if you want a policy solution, I’m inclined to think that a better intervention would involve widespread population BP screening and incentivizing providers to prescribe (and patients to take) antihypertensives. Polypills—which include, e.g., antihypertensives, aspirin, and statins—also look really promising and do more than just reduce hypertension, although pharmaceutical companies have little incentive to make these. So I’d also be eager to see policy solutions aimed at making polypills more widely available.
“Public Health England has estimated that 85% of the salt people ingest is already in food at the point of purchase and consumers only add the other 15% during cooking or at the table.”
https://www.theguardian.com/society/2022/jun/21/uk-needs-to-tax-salt-in-the-same-way-it-does-sugar-says-heart-charity
Anecdotally, people add less salt to the food they cook themselves than is added to processed foods in the factory. If this is true, even if people do ‘top up’ salt levels in their food, they will likely still end up with less salt.
Plus there’s salt in all sorts of crazy things like breakfast cereal. If that gets reduced, I don’t think people are going to start salting their fruit loops.
Thanks for the feedback!
(1) My understanding is that literal packs/shakers of salt sold in supermarkets would not be exempt from the sodium tax. But that raises more dramatic political problems (e.g. at a $0.3 per mg tax, that increases a 500g packet of salt by 100x), and I presume the per mg tax on literal raw salt would have to be far lower. In general, I do agree that substitution with home food is a worry, though there will also be frictions (i.e. not perfect substitutes because of the social element, time needed to cook, etc).
(2) I’m not sure if this is a significant concern—it depends on your frame of reference, and one could easily argue the opposite (e.g. more aggressive sin taxes normalizes them/shifts the overton window, so even if the extreme version gets rejected, people see the more conventional ones like on tobacco and alcohol as reasonable by comparison). In general, I’m not sure if we have strong reason to believe one way or another.
(3) I think I’m fairly deferential to the scientific consensus in this area, which seems strong—it’s something I’ll definitely look more closely into via expert intervews.
(4) & (5) Generally, direct delivery (whether of medication or general checkups/treatments) is a lot more expensive due to (a) actually requiring ongoing resources, and (b) counterfactual costliness, for an EA charity. I agree that they could be promising, but in the context of a shallow review I made the call to focus on what seemed to be the most impactful solution—I could be wrong!