Potassium and health.
Potassium was identified as a shortfall nutrient by the Dietary Guidelines for Americans 2010 Advisory Committee. The committee concluded that there was a moderate body of evidence of the association between potassium intake and blood pressure reduction in adults, which in turn influences the risk of stroke and coronary heart disease. Evidence is also accumulating of the protective effect of adequate dietary potassium on age-related bone loss and reduction of kidney stones. These benefits depend on organic anions associated with potassium as occurs in foods such as fruits and vegetables, in contrast to similar blood pressure-lowering benefits of potassium chloride. Benefits to blood pressure and bone health may occur at levels below current recommendations for potassium intake, especially from diet, but dose-response trials are needed to confirm this. Nevertheless, intakes considerably above current levels are needed for optimal health, and studies evaluating small increases in fruit and vegetable intake on bone and heart outcomes for short periods have had disappointing results. In modern societies, Western diets have led to a decrease in potassium intake with reduced consumption of fruits and vegetables with a concomitant increase in sodium consumption through increased consumption of processed foods. Consumption of white vegetables is associated with decreased risk of stroke, possibly related to their high potassium content. Potatoes are the highest source of dietary potassium, but the addition of salt should be limited. Low potassium-to-sodium intake ratios are more strongly related to cardiovascular disease risk than either nutrient alone. This relationship deserves further attention for multiple target tissue endpoints.
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In summary, benefits of potassium on bone are seen typically when given as organic salts at relatively high doses of 60 to 90 mmol/d (2400–3600 mg/d). Organic salts of potassium reduce urinary calcium loss and improve calcium balance at these levels. But whether that is related to protection against skeletal buffering of an acidogenic diet is still a topic for debate. Perhaps acid-base balance is not the mechanism in healthy kidneys, but as kidney function declined with age, it may be an important mechanism. The glomerular filtration rate declines by as much as 50% from age 20 to 80 y (68), or perhaps excess acid only affects bone through interaction with receptors on bone cells to stimulate bone turnover, and this process is reduced by the alkaline organic salts of potassium.