For years, we’ve been told to cut back on sodium and to avoid using the salt shaker. These guidelines are based on studies suggesting that a high-sodium diet increases the risk of heart disease and high blood pressure. But, recently the low-sodium mantra has quieted to a whisper – but why?
Western diets are certainly high in sodium. In fact, the Centers for Disease Control and Prevention points out that the average American consumes around 3,400 grams of sodium daily. Most of this sodium comes from highly processed foods, the kind of foods that also cause a sharp rise in blood sugar.
But, more recent studies don’t necessarily support the idea that Western diets are too high in salt. In fact, a new study carried out by researchers at McMasters University suggests that for most individuals, the amount of sodium in the standard American diet doesn’t increase the risk of heart disease and stroke. How do we know this?
In this study, researchers followed 94,000 middle-aged people from 18 countries worldwide for 8 years. What they found was health risks were higher only in people who consumed more than 5 grams of sodium daily, the equivalent of about 2.5 teaspoons of salt. Most countries, with the exception of China, consume less than this quantity of sodium each day.
In fact, the study found an inverse correlation between sodium consumption and the risk of heart attack and premature mortality among people who consumed less than 5 grams of sodium daily. However, the risk of heart attack and stroke was elevated in those who consumed more than this amount. So, 5 grams daily seems to be the upper limit of what is safe to consume.
Does the World Health Organization need to update their guidelines? They currently recommend consuming less than 2 grams of sodium daily. But now the evidence suggests that consuming this amount or less offers no health benefits and could actually be harmful, especially if you’re athletic and lose a lot of sodium and other electrolytes through sweating. In fact, a study published in the American Journal of Medicine found that low-sodium intake was correlated with a higher risk of heart disease.
Potassium Helps Your Body Better Handle Sodium
Sodium and potassium are inextricably linked in terms of regulating blood pressure. Unfortunately, most of us don’t get enough dietary potassium – and that can be deleterious to health. In fact, a study showed that the risk of heart attack and stroke dropped with higher consumption of potassium. Research suggests that up to half of people don’t consume enough potassium on a daily basis. That’s not surprising since the best source is fruits and vegetables.
What is more important than the total amount of sodium or potassium in your diet is the ratio of these two electrolytes. A study published in the Archives of Internal Medicine showed that a lower ratio of sodium to potassium in your diet is best for optimal heart health. So, increasing the amount of potassium in your diet helps compensate for sodium. In fact, the study showed that a lower sodium to potassium ratio was linked with a lower risk of heart disease and all-cause mortality.
What is a healthy sodium-to-potassium ratio? According to Harvard Health, hunter-gatherers took in far more potassium than modern day men and women do. The ratio was around 1 to 16, whereas today, it’s more common for people to get a ratio of 1.36 to 1. That’s a big difference! Why are we getting so little potassium? More people eat highly processed foods and fewer fruits and vegetables and processed fare tend to be low in potassium.
Sodium and potassium are carefully regulated by the body. The level of one influences the level of the other. For example, when you consume enough potassium, your kidneys more readily excrete sodium and water into the urine. So, potassium reduces the impact sodium has on the body.
One Precaution
It’s questionable whether a low-sodium diet offers benefits, but if you eat a heavily processed diet, you may be getting more sodium than you think. As the study suggests, you shouldn’t consume more than 5 grams of sodium daily. When you consider that a cup of canned soup and a turkey sandwich made from processed meat contains more than 2 grams of sodium, you can see how quickly it adds up.
Also, there is a sub-population of people who are sodium sensitive. Research shows that around 10% of African Americans develop elevations in blood pressure after consuming sodium-rich foods and should limit their sodium intake. Some research also suggests that overweight people and women may be more sensitive to a high-sodium diet than men and normal-weight individuals.
But, one thing we can all benefit from is a diet that contains sufficient potassium. The exception would be people who have certain medical conditions, such as chronic kidney disease, who need to restrict potassium and those taking certain medications that cause the body to retain potassium.
Another question is whether a high-sodium diet is harmful in other ways. Sodium may have other deleterious effects, as one study showed. Of concern is a study discussed on Medical News Today. It found that consuming a diet high in sodium may kill beneficial bacteria called Lactobacillus that help to maintain “peace” in the gut. These bacteria help to keep more aggressive bacteria from gaining a foothold in the gut. In mice, destruction of these bacteria by a high-salt diet created inflammation and was linked with a rise in blood pressure.
The Bottom Line
Research now questions prior studies that suggest a low-sodium diet is better for health. But, this doesn’t mean you should have no regard for the amount of sodium in your diet. The standard American diet contains an abundance of sodium already and a shortfall of potassium. So, focus on eating more whole, unrefined foods, particularly fruits and vegetables, that are higher in potassium rather than drastically restricting sodium. But, talk to your doctor first to make sure you’re not sodium sensitive.
References:
Centers for Disease Control and Prevention. “Get the Facts: Sodium and the Dietary Guidelines”
Science Daily. “Pass the salt: Study finds average consumption safe for heart health”
The Lancet, 2018; 392 (10146): 496 DOI: 10.1016/S0140-6736(18)31376-X.
Up-to-Date. “Salt intake, salt restriction, and primary (essential) hypertension”
Harvard Health Publishing. “Sodium/potassium ratio important for health”
Science Daily. “Raising dietary potassium to sodium ratio helps reduce heart, kidney disease”
Medical News Today. “High-salt diet may kill off ‘good’ gut bacteria”
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