 Like any group with vested interests, the food industry resists regulation. Faced with a growing scientific consensus that salt increases blood pressure, major food manufacturers have adopted desperate measures to try to stop governments from recommending salt reduction. Rather than reformulate their products and save lives, manufacturers have lobbied governments, refused to cooperate, encouraged misinformation campaigns, and tried to discredit the evidence. After all, salt is the main source of flavor in processed foods. Of course, they could improve the flavor by adding real ingredients, but like making a pop tart with actual strawberries would be more expensive, cut into profits. The evidence that they're trying to discredit includes double blind, randomized trials dating back decades. You take people with high blood pressure, put them on a sodium-restricted diet and their blood pressure drops. Then if you keep them on a low salt diet and add a placebo, nothing happens. But if you instead give them salt in the form of a time-release sodium pill, secretly, their blood pressure goes back up. And the more sodium you secretly slip them, the higher their blood pressure climbs. Even just a single meal can do it. If you take people with normal blood pressure, give them a bowl of soup, containing the amount of salt a regular meal might contain, and your blood pressure goes up over the next three hours, compared to the same soup with no added salt. Why, though? High blood pressure appears to be our body's way to push out excess salt out of our system. Dozens of such studies have been done, showing that if we reduce our salt intake, we can reduce our blood pressure, and the greater the reduction, the greater the benefit. The so-called dash diet, which I've covered before, commonly used to capture the blood pressure benefits of a more plant-based diet. But how do we know the benefits had anything to do with eating less salt, instead of just eating more fruits and vegetables? Because it was put to the test. Sure, eating healthier lowers blood pressure no matter how much salt we eat, but even if we stick to the same diet, lowering salt helps independently of other dietary improvements. You can do this on a community level. You take two matched villages that both start out about the same, and the control village on average, blood pressures went up and or stayed the same. But in the village where they were able to cut down on salt and take blood pressures went down. Whereas if we don't cut down, a chronic high salt intake can lead to a gradual increase in blood pressure throughout life, as shown in the famous InterSalt Study. 52 centers from 32 countries participated with hundreds of participants. Each and four of those centers were in populations that ate so little salt, they actually complied with the American Heart Association guidelines for salt reduction, something less than 1% of Americans achieve. In a population where everyone makes the cutoff, not a single case of high blood pressure was found, not one case of high blood pressure, but not only that, the older folks had the same blood pressure as the teenagers. This is why including such populations is so important. If you just look at the 48 centers in the industrialized Western world, there does not appear to be any relationship between rising blood pressure with age and how much sodium people are getting every day, right? It just looks like a random assortment of dots. Now the salt industry looks at this and says, Aha! See, I told you so, no relationship between salt and increasing blood pressures as you get older. But maybe that's because they're all getting too much salt. The American Heart Association recommendations is that everyone get their salt and takes under here, so they're all way over. You can imagine a similar result if this was instead lung cancer rates versus packs of cigarettes smoked every year. Whether you smoked 150 packs a year or 200 packs a year might not make much of a difference. To see a relationship between smoking and cancer, you'd have to compare smokers to those who rarely light up. And indeed, if you add in those low salt populations, they get little or no high blood pressure as they get older, and you end up with a highly statistically significant relationship between increasing sodium and increasing blood pressure. But only if you include people that actually comply with the salt guidelines, as with so many lifestyle interventions, they only work if you actually do it.