Exploring the sense and nonsense of food and health

To Salt or Not to Salt?

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Which is it – Low salt-high salt, or it doesn’t matter?  In the past several weeks, a huge nutrition controversy had emerged based on a study published in the Journal of the American Medical Society in which the authors even seem confused since they had no firm explanation for the results.

The study measured sodium content in urine (supposedly the gold standard for sodium intake) in 3, 681 healthy Europeans.  After 8 years, 6% of the subjects had some cardiovascular event (heart attack, stroke, e.g.) among which one-third were fatal.  Those who consumed the least salt had a 56% higher risk (yes higher) risk of death from a heart attack or stroke than those who had the highest consumption, after controlling for obesity, cholesterol, smoking, diabetes, and other risk factors.

There are problems with this study – first of all there was only one measurement of urinary sodium over a 24-hour period.  This hardly reflects the sodium intake over the course of the eight-year study.  Secondly, the participants were white, fairly young (less than 60 years of age), and healthy, had normal blood pressure, and were slightly slimmer than the average person.  Previous research has shown that people with hypertension, blacks, older people, and heavier people tend to react more negatively to higher sodium intakes which would have been a better of group to study in this case.

People with the highest intake of sodium did have some association with higher systolic blood pressure measure but  the effect was small.

We also know that not everybody is sensitive to salt – whether they have hypertension or not.  Even in people with high blood pressure, only about half of them are sensitive and in the general population, the estimate is only about 10% or less.

Another study in 2009 called the Trials of Hypertension Prevention, published in the Archives of Internal Medicine, also raises some questions about the effects of sodium in our diets.  This study suggests that people trying to lower their blood pressure should increase their intake of potassium, which has the opposite effect to sodium.  Average sodium and potassium intakes were measured by the intermittent collection of 24-hour urine samples, once for 18 months and again for 36 months.

The study included 2,974 patients, aged 30-54 years at the start of the study, who had blood pressure readings just under levels considered high.  They were followed for 10-15 years to see if they would develop cardiovascular disease.

The Results:  Those with the highest sodium levels in their urine were 20% more likely to suffer strokes and heart attacks compared with their counterparts with the lowest sodium levels.  However, this association was not statistically significant.

But, the participants with the highest sodium-to-potassium ratio in urine were 50% more likely to experience cardiovascular disease than those with the lowest sodium-to-potassium ratios and this association was statistically significant.

A more recent study published in the Archives of Internal Medicine, (2011; 171:1183-1191) supports this theory. Researchers looked at the long-term effects of sodium and potassium intake in a 15-year study of more than 12,000 people.

By the end of the study 2,270 people had died; 825 of these from heart disease and 433 from blood clots and strokes.  The key finding was that the people who had a high salt intake and a low potassium intake were most at risk.

“People who ate a diet high in sodium and low in potassium had a 50% increased risk of death from any cause, and about twice the risk of death – or a 200% increase- from a heart attack”, said Dr. Elena Kuklina from the CDC, one of the lead researchers of the study.

The 2010 Dietary Guidelines for Americans recommend limiting sodium to less than 2,300 mg a day — or 1,500 mg if you’re age 51 or older, or if you are black, or if you have high blood pressure, diabetes or chronic kidney disease. Keep in mind that 1 teaspoon of salt contains 2,325 mg. of sodium. The average American gets about 3,400 mg of sodium a day — much more than recommended.  Most of the sodium in foods comes from processed and restaurant foods.  The more processed a food is, the less potassium it contains.

Nevertheless, the people at Campbell Soups are going with the consumer. They recently have decided to increase their regular soup sodium content due to sagging sales in order to improve their taste.  They will keep the Healthy Request line with lower sodium content alone.

The recommendation for potassium is 4.7 grams of potassium from foods, unless they have a clinical condition or medication need that is contraindicated to increase potassium intake.
Potassium is a very important mineral for the proper function of all cells, tissues, and organs in the human body. It is also an electrolyte, a substance that conducts electricity in the body, along with sodium, chloride, calcium, and magnesium. Potassium is crucial to heart function and plays a key role in skeletal and smooth muscle contraction, making it important for normal digestive and muscular function, too.  Many foods contain potassium but the primary food sources are potatoes, squash, lima beans, tomatoes, bananas, oranges, avocados, meats, dairy products, and coffee.

Cautions about potassium supplements:

As with all nutrients, it is best to get them from foods, not supplements and especially potassium.  Potassium supplements, other than the small amount included in a multivitamin, should be taken only under your doctor’s supervision.

  • Do not give potassium supplements to a child unless your doctor tells you to.
  • People with hyperkalemia (high blood potassium) or kidney disease should not take potassium supplements.
  • People who take ACE inhibitors, potassium-sparing diuretics, or the antibiotic trimethoprim and sulfamethoxazole (Bactrim, Septra) should not take potassium.

So step away from the salt shaker.  Salt intake has been rising since the 1970’s.  Most health experts still think that consuming too much salt is not good for you and that cutting salt intake can reduce high blood pressure in some people, and now it appears that this may be more effective along with a diet high in potassium.

A suggestion:  If you are a salt lover and food tastes terrible without it, try a low-salt diet for at least 3-6 weeks; then after that you get accustomed to it and everything you eat tastes salty.  I’ve tried it – it works.

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