Hypertension, But not "Prehypertension," Increases Stroke Risk -- and Should Combination Therapy Include a Calcium Antagonist?

March 16, 2004

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Americans and Canadians Urged to Cut Down Salt and Increase Potassium Intake

The majority of men and women in the United States and Canada consume too much salt (sodium chloride) and not enough potassium, leading to increased blood pressure and consequent risks of stroke, coronary heart disease, and kidney disease, a new report by the US Institute of Medicine says.[18] The report is the latest in a series of dietary recommendations for the intake of nutrients. This series of reports is sponsored by a number of US and Canadian government organizations, foundations, and corporate donors. The recommendations are based on comprehensive literature reviews.

The latest recommendation is that healthy 19- to 50-year-old adults should consume 1.5 g of sodium and 2.3 g of chloride, equivalent to 3.8 g of salt, per day, to replace the amount lost through perspiration and to achieve a diet that provides sufficient amount of other essential nutrients. The recommended tolerable upper intake level (UL), ie, the maximum amount that should not be exceeded for salt, is 5.8 g (2.3 g of sodium). (JNC 7 recommends a maximum dietary intake of sodium chloride of 6 g per day.) Exceptions are the elderly, African Americans, and people with chronic diseases such as hypertension, diabetes, or kidney disease, who are especially sensitive to the blood pressure-raising effects of salt and who should therefore consume less than the UL. The report notes that currently in the United States, more than 95% of men aged 31-50 years and 75% of women in the same age range regularly consume more than the UL. The comparable figures for Canadian men women of the same age are 90% and 50%, respectively, the report says.

The diet of most people in the United States and Canada is also low in potassium, according to the report, which recommends an adult intake of at least 4.7 grams per day to lower blood pressure, blunt the effects of salt, and reduce the risk of kidney stones and bone loss. American women apparently consume no more than half this recommended amount, at 2.2-2.4 g per day, and men only slightly more, at 2.4-2.6 g per day. Canadians fare slightly better, at 3.2 -3.4 g per day for men and 2.6-2.6 g per day for women. The report notes that there is no evidence of chronic excess intake of potassium and, therefore, no UL has been established.