To me, the story of salt strongly highlights the difference between science (as in, the results of scientific experiments and careful reasoning), and "science", the things the general public is told science has found by journalists and policymakers.
Not only was there was never a strong scientific basis for telling people to reduce their salt intake, my anecdotal observation is that it's fairly easy to wind up salt-deficient and get symptoms. Sweat contains salt (1g/L), so when exercising or in high temperatures, I need to eat more of it, or I'll get fatigued and physical exertion will become impossible. (Sweat also makes exercise a confounder in studies that look at urinary excretion.)
Meanwhile, foods that we think of as "salty" are usually not actually salty, but rather, are designed to create salt pica. If you start eating potato chips, with most American brands, you'll get to 2000 calories before you get to a typical salt intake (which is 3.5g).
The kosher salt in my cupboard (ingredients: salt and an anti-caking agent) is 40% sodium by mass (480 mg sodium per 1.2 grams). Or, going by the atomic mass listed here ( http://www.chemicalelements.com/show/mass.html ), sodium chloride should be 39% sodium by mass. Assuming an even 40%, that's 3 grams of salt (NaCl) in 2000 Calories of american potato chips. (Or, assuming the less generous actual amu ratio, 3.05 grams of salt per 2000 Calories ;D )
HOWEVER: the nutrition label also indicates almost twice as much potassium (330 mg) as sodium. If that potassium is also salt (KCl), the chips will handily exceed 3.5 grams of salt per 2000 Calories.
If that's true, those potato chips should be made with a lot more sodium. (Or, you know, some more sodium and less potassium. I don't think people would eat the "now with 62% more table salt" version of the chips.)
The major difference appears to be the label's use of "salt" rather than "sodium" as in the US.
Using the data from my other comment, and assuming the potassium in the potato chips is also "salt", the 2000 Calories of US potato chips contain 7.25 grams of salt, of which 3.05g is sodium chloride and 4.2g is potassium chloride.
Indeed, things you think are salty are not the foods you get most your salt intake from. The biggest source of salt in your diet is actually often bread! Typical store-bought bread is around 0.75g of salt per 100g. Several EU countries recommend a daily intake of 250g of bread, which gives you the same amount of salt as a 100g bag of potato chips.
Back on the farm we always had a bottle of 'salt pills' on the dashboard of the pickup. Anybody who felt the effects of the sun was encouraged to suck on one.
Problem is: the real scientists didn't speak out loudly.
And, the bigger problem: many of them as well as others have very good reasons for keeping shut. Few people want to be vilified by mainstream media and the PC crowd.
"X pica" in my local dialect means "doing something because you need or want X, when that doesn't provide it". It's a generalition of the medical condition pica, which is eating non-food things like ice cubes because you need more iron.
It's a public health thing, no? If they tell 10,000 people to decrease their salt intake, they've saved (made up figure) 10 lives. So they say everyone decrease salt, rather than the more nuanced message which is "Salt might be dangerous for some people."
> ...the less sodium that study subjects excreted in their urine—an excellent measure of prior consumption—the greater their risk was of dying from heart disease
When you have no idea about the consequences of an act, the right thing to do is not to go out and tell everyone to do it.
How many of the 10,000 are you endangering by cutting their sodium intake? Worse yet, you are not cutting their potassium intake. What long term consequences will it have on their muscular and nervous systems? Nobody seems to know.
And the point is moot anyway. It's not like we can't detect sodium sensitivity. In fact, it's almost certainly easier to discover who those 10 people are than to get the population to reduce their sodium intake.
Not only was there was never a strong scientific basis for telling people to reduce their salt intake, my anecdotal observation is that it's fairly easy to wind up salt-deficient and get symptoms. Sweat contains salt (1g/L), so when exercising or in high temperatures, I need to eat more of it, or I'll get fatigued and physical exertion will become impossible. (Sweat also makes exercise a confounder in studies that look at urinary excretion.)
Meanwhile, foods that we think of as "salty" are usually not actually salty, but rather, are designed to create salt pica. If you start eating potato chips, with most American brands, you'll get to 2000 calories before you get to a typical salt intake (which is 3.5g).