SODIUM VERSUS POTASSIUM: WHICH ONE WINS, AND WHY?

We have long known that the mineral, potassium, is a healthy component of a normal diet and likely provides more benefit than does its counterpart, sodium. For instance, reducing sodium in the diet has been recommended to lower blood pressure and the risk of heart disease. However, in a new review article, researchers found that increasing dietary potassium is as important to improving the risk factors for cardiovascular and kidney disease as limiting dietary sodium. From a review of more than 70 studies, they found that the interaction of sodium and potassium can account for more healthy blood pressure levels. When dietary potassium intake is elevated, the kidneys – composed of millions of small tubes working together – shift fluid to the area near the end of the tubes where potassium secretes into the urine. This shift reduces the amount of sodium and water that’s reabsorbed into the body. In this way, high potassium diet signals the body to reduce the amount of sodium that is retained. This reciprocal pattern regulates the levels of both minerals in the body, which in turn helps lower blood pressure. Higher intake and excretion of potassium has also been found to slow the progression of kidney and heart disease.
One important means to increase potassium intake is through the use of salt substitutes, which usually consist of potassium chloride (KCL). Many people object to this product, however, because of its somewhat bitter aftertaste, which may be less desirable than salt (NACL) itself. In fact, for many people the two substances are similar enough in flavor that they find it easy to switch to KCL. But if the taste of the potassium chloride doesn’t work for you, there are so-called “lite” salt replacements. They’re often labeled “low sodium” and contain a blend of sodium chloride and potassium chloride. These salt substitutes have a more salty taste, yet have less sodium chloride than traditional table salt. However, since these lite salt replacements do contain a degree of sodium chloride and you need to go easy.

One warning: The potassium in salt substitutes may be dangerous for some people. Anyone who has kidney disease or is on certain hypertension medications should not increase their potassium intake unless it’s approved by their physician.

FINDING A HAPPY MEDIUM

A mixture of sodium and potassium provides a low-sodium salt substitute that tastes more like ordinary table salt and potentially has major public health benefits. According to a recent landmark study, such a mixture resulted in a reduction in stroke, cardiovascular events, and death.

The Salt Substitute and Stroke Study (SSaSS) was conducted in 21,000 people with a history of stroke or high blood pressure in rural China, with half of them using a lower-sodium salt substitute instead of regular salt. Results showed that after 5 years, those using the salt substitute had a 14% reduction in stroke, a 13% reduction in major cardiovascular events, and a 12% reduction in death. These benefits were achieved without any apparent adverse effects. The study appeared in the New England Journal of Medicine. According to it’s lead author, “This is one of the largest dietary intervention trials ever conducted and has shown very clear evidence of protection against stroke, cardiovascular events, and premature death, with no adverse effects with a very simple and low-cost intervention. It is a very easy thing to work into the diet. You just replace regular salt with a substitute that looks and tastes almost identical.”

There are numerous low-sodium mixtures on the market, among which are Morton’s Lite Salt that provides KCL with about 50% less sodium. (Disclaimer: I have no financial interest in this company)

THE BIG PICTURE FOR POTASSIUM

The way the body manages sodium and potassium and the association with blood pressure is highly consistent across different populations. Almost everyone, with the exception of a few people with serious kidney disease, should be avoiding salt or switching to a salt substitute and expect to see some resulting benefit.

Hypertension expert Bryan Williams, MD, University College London, said the SSaSS was “probably the most important study with regards to public health that we will see.” He described the reductions in stroke, cardiovascular events, and death as “extraordinary for such a simple intervention.” Dr. Williams added: “Those who have doubted the benefits of salt restriction must now admit they were wrong. The data are in. Global health interventions to implement these findings must now begin.” He also highlighted the large number of events in the trial. “This was a large, pragmatic, long-duration study in a high-risk population, and with 5,000 cardiovascular events it gives enormous power to show benefits.”

FOOD MANUFACTURERS SHOULD MAKE CHANGES

Dr. Neal acknowledged that a limitation of the study was the fact it was conducted in a single country, which would raise issues of generalizability. But he said he believes the results are applicable to other populations. Those who would get the most benefit from switching to a salt substitute are those who consume large amounts of discretionary salt – salt added at home at the time of cooking for preservation of food or seasoning. This is salt that is easy to replace with salt substitute.

There are more than 5 billion people in the world that consume more than 50% of their salt intake as discretionary salt – mainly in the developing world. These people would expect to get significant health benefits from a switch to salt substitute. I would add that salt substitute is low cost and is easy to manufacture, costing around 50% more than regular salt, but this translates into just a dollar or two per person per year to make the switch. The results also apply to higher-income countries, as most salt in these countries comes from processed foods.

This study provides strong evidence for food manufacturers, who should switch to using salt substitute products to be widely available on supermarket shelves. Governments should also take action to promote use of salt substitutes over regular salt. This could take the form of taxing regular salt or subsidies for use of salt substitutes.

But lets explore further some general facts about potassium, which is also needed for normal muscle growth, and for nervous system and brain function. In addition to reducing blood pressure, potassium seems to work by protecting blood vessels from damage and excessive thickening. This mineral is found in various foods, especially fruits and vegetables. Ironically, these are the same foods that are associated with better cardiovascular health, a fact that prompts the question: Could the contained potassium be the main component that accounts for such robust heart health attributed to these foods? Probably not, because there are additional components that could also contribute toward the same ends, but the question is intriguing!

HOW MUCH POTASSIUM IS GOOD?

Although there is some debate regarding the optimal amount of dietary potassium, most authorities recommend a daily intake of at least 4,700 milligrams. Most Americans consume only half that amount per day, which would make them deficient in regards to this particular recommendation. Likewise, in the European Union, insufficient potassium intake is common. In a large pooled analysis, Italian researchers reported in 2011 that by raising one’s daily intake of potassium by 1,640 milligram, you could expect a 21% lower risk of stroke. Even greater benefits can be achieved if we combine increased potassium with reduced intake of sodium, which should contain no more than a total of 2,300 mg daily (note: sodium makes up approximately 40% of table salt.).

In order to get 4,700 mg of potassium a day, try to get your intake from healthy eating. Augmenting potassium intake as needed with a salt substitute, as noted above, can be useful. Also, foods containing liberal amounts of potassium usually also possess other valuable nutrients that promote health in other ways. Several delicious foods can help you reach your potassium goal.

Here is partial list of such foods: Sweet potatoes, tomatoes, beets and beet greens, white beans, yogurt, clams, prunes, apricots, carrots, molasses, fish, soy, squash, bananas, milk, and orange juice.

So these suggestions should provide you with an easy—and pleasurable—way to achieve better health and longevity!

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