POTATO CHIPS, POPCORN, PRETZELS, NUTS. THESE POPULAR FOODS ALL have something in common—lots of salt. Many people find a salty taste pleasant, but salt does more than simply add saltiness. It can also enhance sweetness and hide unpleasant metallic or chemical flavors, rounding out the overall balance
of flavors and improving the taste of food. Flavor can also be enhanced by adding herbs,
spices, and vinegars, but adding salt is a cheap and easy way to make food taste good.
Unfortunately, taking too much salt has been associated with high blood pressure,
which can damage the heart and blood vessels and increase the risk of a heart attack and
stroke. For decades, the U.S. government and the American Heart Association have rec-
ommended consuming less salt. But reduced consumption of salt has not been shown to
reduce blood pressure much and has not led to a decrease in heart attack and stroke in
the U.S. population. Yet current guidelines still call for limiting salt intake to stay healthy.
So how much salt do we actually need to take to stay healthy?
Health effects of salt
Cutting back on salt can reduce blood pressure, but often, the change in blood pressure is small. According to the American Heart Association, a person who reduces
salt intake from median levels (around 3,400 milligrams (mg)) to the federally recommended levels (no more than 2,300 mg) typically sees a slight drop of 1% to 2% in
blood pressure, on average.
Also, other factors affect blood pressure. For example, blood pressure increases with
weight gain and decreases with weight loss. So, keeping a healthy weight can help prevent high blood pressure. Eating foods high in potassium also seems to counter some of
the effects of high salt consumption on blood pressure.
Studies comparing salt intake in different countries worldwide have not found a clear
connection between salt intake and high blood pressure. Societies that eat lower levels of
salt do not necessarily have less heart disease than those that eat a lot of salt.
In addition, salt directly affects other nutrients. For instance, consuming a lot of salt
may cause more calcium to be excreted in the urine. Calcium is a mineral that helps to
strengthen bones, so people on a high-salt diet may need more calcium to make up for
the calcium lost (along with the excess sodium). Also, urinary calcium, the main constituent of kidney stones, is increased by a high-salt diet. Therefore, a high-salt diet can
lead to painful kidney stones.
By Chris Eboch
ChemMatters | FEBRUARY/MARCH 2016 11