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Can Potassium Counteract High Sodium?
Most people know that high sodium intake raises blood pressure. A recent study indicates that potassium intake is equally important in helping to lower blood pressure, echoing information presented in an earlier article by TheDoctor's nutrition specialist, Dr. Robert M. Russell of Tufts University and Paolo M. Suter, M.D, Chief of the Hypertension Clinic at the University Hospital, Zurich, Switzerland.
Unlike most dietary studies, which obtain their information indirectly from people's recall or records, this one measured the actual sodium and potassium content of participants' urine. The researchers found that the participants with the highest risk of cardiovascular complications were those whose urinary sodium was very high in comparison to their urinary potassium. High urinary sodium in itself was not a reliable indicator of future heart problems.
Paul Whelton, senior author of the study, summarizes: "[P]otassium 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."
Whelton, an author or co-author of over 400 papers on high blood pressure, was also a member of a 2004 panel formed to set dietary standards for sodium and potassium consumption. The panel recommends that healthy 19-50 year olds should consume no more than 2,300 milligrams (2.3 grams) of salt a day — about one teaspoon. The panel also recommends that adults consume 4.7 grams of potassium daily, unless they have a medical condition or are taking a medication that forbids this. Currently, most adults consume more salt than recommended and only about half the recommended amount of potassium.
Many different types of food are rich in potassium. These include potatoes and sweet potatoes, milk and yogurt, beans, bananas, tomato products, fish, raisins and orange juice. Something for nearly every taste. A detailed listing of the potassium content of foods, compiled by the U.S. Department of Agriculture, can be found at http://www.nal.usda.gov/.
All animal cells have a sodium-potassium pump, which concentrates the potassium inside cells while also expelling sodium. Running this pump takes a good deal of energy, with estimates running as high as half of a cell's total energy. This give you an idea of the length your body goes to maintain its potassium level.
The study was of 2,974 participants, initially aged 30-54. The participants' initial blood pressure was just below the level considered high, and their cardiovascular health was tracked for 10-15 years. 24-hour urine samples were collected intermittently during two separate trials, one lasting 18 months, the other 36 months, and urinary sodium and potassium were measured.
The study was published in the January 12, 2009 issue of the Archives of Internal Medicine.
February 18, 2009
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