That’s the message from the American Heart Association (AHA) in its latest advisory. The AHA takes issue with recent studies disproving a link between salt and heart-disease risk that it says have been “widely misinterpreted.” It also re-affirms its 2011 recommendation that all Americans should limit their sodium intake to just 1,500 mg per day — less than the amount found in a single teaspoon of table salt (sodium chloride). The typical American now eats more than twice that amount.
“Americans of all ages, regardless of individual risk factors, can improve their heart health and reduce their risk of cardiovascular disease by restricting their daily consumption of sodium to less than 1,500 mg,” AHA chief executive officer Nancy Brown said in a statement.
The data on salt and its impact on health, however, has been confusing and often conflicting. That’s because it’s challenging to design the fool-proof study that isolates just the effect of salt, and not other diet or lifestyle factors, from health outcomes like heart disease and hypertension. In addition, most studies rely on participants’ recollection of what they ate, a notoriously unreliable measure of dietary intake. Measuring sodium levels in urine is more accurate, but also more costly and too intrusive to test a large number of people several times.
Then there is the “reverse causality” effect, in which high blood pressure may actually be linked to lower blood pressure since people with hypertension may have decided to limit their salt intake at the advice of their doctor. According to the AHA, said this may explain several studies published in the past year that found unusual associations between poor heart health and low sodium intake.
Still, experts agree on one thing: that whatever the healthy cut-off is for salt intake, most Americans are eating way more than we need. The debate is not so much about whether to cut back, but about how much to cut, and who needs to reduce sodium intake the most.
Our bodies need sodium to function, but our consumption in general far outstrips physiological needs, experts say. Guidelines like the AHA’s 1,500 mg per day would allow plenty for an adult or child to function well. About 99% of us consume more than the AHA limit, with the typical American eating on average 3,400 mg. daily.
In the body, excess sodium is filtered out by the kidneys and excreted in the urine. When we take in so much that the kidneys can’t get rid of it fast enough, however, health problems can set in. The extra salt starts to build up in the blood and attract water, which causes blood volume to swell, putting pressure on the vessels and on the heart to work harder to move blood through the body. The result? Higher pressure in your arteries. Over time, elevated blood pressure can boost the risk of heart disease and stroke. It can also lead to heart failure and kidney disease, starting a vicious cycle since both of those conditions make it harder for the kidneys to balance the body’s salt levels.
According to the AHA, high sodium intake is also linked to kidney stones, asthma, osteoporosis, and gastric cancer.
That’s reason enough, says the AHA, to watch your salt intake if you already have high blood pressure, and increasingly, even if you have no symptoms of risk factors for heart disease.
Yet the AHA is among the only major health groups recommending lower salt intake. Unlike the AHA, for example, the U.S. Department of Agriculture (USDA) and the Department of Heath and Human Services say it’s fine for most people to consume as much as 2,300 mg of sodium per day. Those federal agencies recommend the stricter 1,500 mg limit only for people with higher heart risk, including everyone over age 51, all African Americans, and anyone with high blood pressure, diabetes, or kidney disease.
And the best way to keep sodium in check? According to the new AHA advisory, 70% to 80% of the sodium Americans eat comes from packaged or processed foods and sauces, soups, and cured meats. Hidden sources include breads, cereals, salad dressings, and condiments. Substituting fresh foods for packaged foods is a quick way to cut out a lot of sodium; fresh meat contains far less salt than lunch meats, bacon, or sausage, and most fresh vegetables are naturally low in sodium (whereas as canned versions often have salt added).
Other advice from heart-health groups: When you cook at home, you can often leave out some of the salt from recipes. And once your meal is prepared, stay away from the salt shaker. If you do buy packaged foods, it helps to read the labels. Just be aware that those listed daily recommended intakes are based on the USDA’s sodium recommendation of 2,300 mg per day for a healthy person who’s 51 or younger. To follow the AHA’s more stringent limit, you’ll need to eat less. But whether or not you have high blood pressure or not, the AHA says that’s ‘s an effort worth making.