Why Even Healthy People Should Watch Their Salt Intake

Salt is a ubiquitous part of the American diet, but even healthy people should be cutting back to avoid high blood pressure and life-threatening heart disease and stroke.

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.

Is Eating Eggs Really as Bad for Your Heart as Smoking?

Is your breakfast omelet harming your heart? A recent study by researchers at Western University in Canada found that the more egg yolks people ate, the thicker their artery walls became — an indicator of heart disease risk — and that the effect was almost as bad as from smoking cigarettes.

In the study, the researchers measured carotid plaque build-up in the arteries of 1,231 men and women, average age 62, who were seeking care at cardiovascular-health clinics. Participants filled out questionnaires detailing lifestyle habits including medication use, cigarette smoking and egg-yolk consumption. The researchers gauged how much people smoked and how many egg yolks they ate over time, by calculating their “pack-years” (the number of packs of cigarettes people smoked per day multiplied by the number of years they spent smoking) and “egg-yolk years” (how many egg yolks they ate per week for how many years).

After about age 40, participants’ plaque began building up steadily, but among the participants who ate the most eggs — three or more yolks per week — that build-up increased “exponentially,” the study found. As people’s egg-yolk years went up, so did their plaque accumulation — an association that was independent of factors like gender, cholesterol levels, blood pressure, smoking, body mass index and diabetes.

Among the 20% of participants who ate the most eggs, the carotid plaque build-up was about two-thirds that of the study’s heaviest smokers. The researchers concluded that the plaque increase from eating eggs “follows a similar pattern to that of cigarette smoking.”

Arterial accumulation of plaque is a key risk factor for heart attack and stroke. As plaque builds up, it thickens artery walls and narrows the space through which blood can flow, forcing the heart to pump harder. If plaques become unstable, they can break off and form clots, which can halt blood flow to either the brain or the heart, causing stroke or heart attack.

The authors argue that their findings should quell doubts over the link between high dietary cholesterol and heart disease. “The prevailing tendency to ignore dietary cholesterol as a risk factor for coronary heart disease requires reassessment, including the consumption of cholesterol from eggs,” the authors wrote.

The government’s dietary guidelines recommend that adults consume no more than 300 mg of cholesterol a day. One whole egg contains about 180 mg of cholesterol, nearly two-thirds of your daily recommended ma.

“The mantra ‘eggs can be part of a healthy diet for healthy people’ has confused the issue. It has been known for a long time that a high cholesterol intake increases the risk of cardiovascular events, and egg yolks have a very high cholesterol content,” study author Dr. David Spence, a professor of neurology at western’s Schulich School of Medicine & Dentistry, said in a statement. “In diabetics, an egg a day increases coronary risk by two- to five-fold.

However, the study’s findings raised brows among other health experts, ABC News reports:

Cardiologists say the study shouldn’t be taken so seriously because the research is flawed.

“This is very poor quality research that should not influence patient’s dietary choices,” said Dr. Steven Nissen, who chairs the department of Cardiovascular Medicine at the Cleveland Clinic Foundation, in an email. “It is extremely important to understand the differences between ‘association’ and ‘causation’.”

Nissen said the researchers relied on patients to recall how many eggs they consumed, but asked them once and assumed it remained constant, which isn’t reliable. He said the way researchers measured patients’ plaque has come under “considerable criticism,” and that researchers failed to adjust for other dietary factors.

Indeed, it’s possible that the people who ate a lot of eggs also tended to eat a lot of other high-fat, high-salt or high-cholesterol foods. Or maybe they also tended to exercise less.

The researchers say that while further studies are needed to flesh out the association, people at risk for heart disease should still refrain from eating egg yolks on a regular basis.

The study is published in the journal Atherosclerosis.