February 03, 2009
Sodium Potassium Ratio Most Important For Heart

The ratio of sodium to potassium in urine is more important than the level of sodium alone for cardiovascular disease risk.

Researchers found that the ratio of sodium-to-potassium in subjects' urine was a much stronger predictor of cardiovascular disease than sodium or potassium alone.

"There isn't as much focus on potassium, but potassium seems to be effective in lowering blood pressure and the combination of a higher intake of potassium and lower consumption of sodium seems to be more effective than either on its own in reducing the risk of cardiovascular disease," said Dr. Paul Whelton, senior author of the study in the January 2009 issue of the Archives of Internal Medicine. Whelton is an epidemiologist and president and CEO of Loyola University Health System.

Researchers determined average sodium and potassium intake during two phases of a study known as the Trials of Hypertension Prevention. They collected 24-hour urine samples intermittently during an 18-month period in one trial and during a 36-month period in a second trial. The 2,974 study participants initially aged 30-to-54 and with blood pressure readings just under levels considered high, were followed for 10-15 years to see if they would develop cardiovascular disease. Whelton was national chair of the Trials of Hypertension Prevention.

Those with the highest sodium levels in their urine were 20 percent more likely to suffer strokes, heart attacks or other forms of cardiovascular disease compared with their counterparts with the lowest sodium levels. However this link was not strong enough to be considered statistically significant.

By contrast, participants with the highest sodium-to-potassium ratio in urine were 50 percent more likely to experience cardiovascular disease than those with the lowest sodium-to-potassium ratios. This link was statistically significant.

You should consume half as much sodium as potassium.

Whelton was a member of a recent Institute of Medicine panel that set dietary recommendations for salt and potassium. The panel said healthy 19-to-50 year-old adults should consume no more than 2,300 milligrams of sodium per day -- equivalent to one teaspoon of table salt. More than 95 percent of American men and 75 percent of American women in this age range exceed this amount.

To lower blood pressure and blunt the effects of salt, adults should consume 4.7 grams of potassium per day unless they have a clinical condition or medication need that is a contraindication to increased potassium intake. Most American adults aged 31-to-50 consume only about half as much as recommended in the Institute of Medicine report.

How to double your potassium intake? Turns out that high potassium foods are things you ought to eat for other reasons too. Beans, tomatoes, prunes, bananas, acorn squash, artichoke, spinach, sunflower seeds, almonds, winter squash, soybeans, cantaloupe, honeydew melon, and lentils all provide high potassium.

Share |      Randall Parker, 2009 February 03 11:25 PM  Aging Diet Heart Studies


Comments
Fat Man said at February 4, 2009 11:22 AM:

Warning. Mineral Potassium Chloride can be toxic, even fatal in quantity. It should only be taken under a physicians supervision. Fruit, nuts, and vegetables are all OK, enjoy yourself.

Aron said at February 4, 2009 1:14 PM:

Does exercise (via sweating) directly compensate for high salt consumption? Is there any heuristic on how much?

bbartlog said at February 5, 2009 12:03 PM:

The conclusion that you should take in less sodium does not seem to be supported by this study. I note that they measured both *intake* and urine levels, but only a result for the urine levels is mentioned. I would assume that if they *had* found a link between sodium intake and heart disease, it would have been described.
There are at least two reasons that sodium levels in the urine could be quite unrelated to sodium intake. One is dehydration. Someone who is chronically dehydrated is going to have higher concentrations of everything in their urine. Maybe they compensated for this by measuring sodium levels in comparison to other dissolved compounds and not simply in terms of micrograms per ml or what have you, but I'm skeptical.
The other reason as another commentator hinted at would be sweating and by extension exercise. Someone who does significant exercise is going to excrete quite a lot of sodium via channels other than the urine; in fact I'd go so far as to guess that high urinary sodium might be a good proxy for being sedentary.

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