The entire field of research around salt is a colossal fuckup, for a fairly simple reason: sweat is salty. If you sweat, due to exercise or high temperatures, you lose about 1g/L of sodium. So right off the bat, all the research that's trying to find a population-wide correct amount of sodium to eat is on a wrong track, because there's no such thing.<p>But it's even worse, because most of the research doesn't measure the amount of sodium people take in through food, it measures the amount of sodium they lose in urine. This isn't their intake, it's what's left after losses, so it's confounded by exercise.<p>And it's even worse than <i>that</i>, because while the actual studies indicate that there's no benefit from cutting salt intake, some high-status organizations once said there was, and are acting as though they can't take it back without losing face.<p>The overall result is that there are a bunch of people shouting "less salt!" and a bunch of people shouting "the same amount of salt!" and no one has any model of how much salt they actually need, so they occasionally end up deficient.
I always find it fascinating how much nutrition as a science is clearly in its infancy. It's true that rigorous science in medicine is relatively recent compared to other fields of study but in nutrition we're still seeing major changes to the consensus and guidelines.<p>My favourite example is probably cholesterol. Nearly everyone instinctively knows that eating too much cholesterol will raise your cholesterol levels and puts you at risk of heart disease. Don't eat too many eggs or you'll go to an early death. The thing is, that view, which has been informed from the advice from authorities over the past few decades, is completely wrong.<p>As the panel determining the Dietary Guidelines for Americans concluded in 2014 - "Cholesterol is not considered a nutrient of concern for overconsumption," and as a result, warnings about cholesterol has since been removed from the guidelines.<p>Obviously the link between dietary and blood cholesterol is more complex than initially thought but it's still staggering to me that such a simple recommendation could have been so wrong and how government guidelines can lag the scientific consensus. It's interesting to see that much the same can be applied to salt and the solution is the same. Eat a variety of food and try to avoid as much processed food as possible.
One thing easily overlooked is that recommendations for sodium intake depend on individual considerations. Sodium restriction may be important in conditions other than hypertension.<p>For example, people who excrete too much urinary calcium are at risk of kidney stones and bone loss. Reducing salt consumption is usually necessary to decrease calcium depletion and prevent bad outcomes.<p>As I've observed it, the chances of people getting too much dietary sodium far exceeds getting too little. The FDA's idea to reduce sodium content of foods is most likely a constructive step forward.
I always wonder why things that taste salty don't seem to have that much sodium. I was eating a bag of salt and vinager chips and could just taste all the salt. I figured I'd be getting 150% of my dv of sodium but no only 9%.