The existence of these meta-analyses is much less convincing than you think. One, because a study of the effect of sodium reduction on blood sugar combined with a study of the effect of antihypertensive medications don’t combine to make a valid estimate of the effect of sodium reduction on a mostly-normotensive population.
But second, because the meta-analyses are themselves mixed. A 2016 meta-meta-analysis of supposedly systematic meta-analyses of sodium reduction found 5 in favor, 3 against, and 6 inconclusive, and found evidence of biased selective citation.
The existence of these meta-analyses is much less convincing than you think. One, because a study of the effect of sodium reduction on blood sugar combined with a study of the effect of antihypertensive medications don’t combine to make a valid estimate of the effect of sodium reduction on a mostly-normotensive population.
But second, because the meta-analyses are themselves mixed. A 2016 meta-meta-analysis of supposedly systematic meta-analyses of sodium reduction found 5 in favor, 3 against, and 6 inconclusive, and found evidence of biased selective citation.