Salt-potassium ratio may trump blood pressure for heart disease

Folks who think low blood pressure means they can consume salt without worry may be in for a surprise. Research suggests that the ratio of sodium to potassium in the diet is more predictive of health risks than high blood pressure is.

Even healthy individuals with normal blood pressure should avoid a “sodium-saturated diet,” according to an eMaxHealth article by Dr. Robin Wulffson.
He’s no lone voice, either.

Centers for Disease Control and Prevention researchers published a recent study in the Archives of Internal Medicine that found an increased risk based on that ratio, as well. The scientists controlled for “all the major cardiovascular risk factors” and still found an association with deaths from heart disease when the sodium-potassium ratio was bad. Sodium raises blood pressure and reduces the elasticity of arteries. Potassium activates nitric oxide, which relaxes arteries and lowers the risk of high blood pressure. Sodium, by the way, blocks uptake of nitric oxide.

The Institute of Medicine last year looked at data from 12,000 American adults and reported that a high-sodium diet increases the risk of heart disease, as has been widely reported. But of greater portent, it said, is the balance between the two chlorine salts: sodium raises risk, while potassium lowers it.
That study concluded that “no one is immune to the adverse health effects of excessive sodium intake.”

Research shows that when the sodium-to-potassium ratio is high, people are nearly 50 percent more likely to die from any cause within the 14.8-year follow-up period and twice as likely to die from ischemic heart disease, compared to those who consumed less sodium than potassium.

Three-fourths of salt in the American diet is eaten in processed foods or at restaurants. Wulffson pointed out that it also comes from water that has run through a water-softener. That can be charged with potassium chloride instead of with sodium chloride, although it costs more.

The human body only needs 220 milligrams of sodium a day; the average diet contains more than 3,400 milligrams a day. Current dietary guidelines cap it at a maximum of 2,300 milligrams for all but those at high risk, who should have no more than 1,500 milligrams a day. That category includes anyone over 50, African-Americans and those with high blood pressure, diabetes or chronic kidney disease.

An article in the New York Times notes that because the Food and Drug Administration categorizes salt as “generally recognized as safe,” food producers can put as much into products as they wish. Writes the Times’ Jane E. Brody, “To make matters worse, not only does the amount of sodium rise precipitously when foods like tomatoes and potatoes are processed, but the natural potassium in these foods declines significantly, worsening the sodium-potassium ratio.”

Wulffson noted that 28 national food companies, retailers and supermarket chains have agreed to the national Salt Reduction Initiative, which targets a 25 percent reduction in sodium in food products by 2014.

The American Heart Association has launched a campaign to make it easy to send comments to the FDA and Department of Agriculture, Food Safety and Inspection Service (FSIS), which have been soliciting suggestions and reaction to reducing sodium consumption. One click and the association links you to their site.

It’s going to take a harder push from the government to really make a change, according to the IOM report. “What is needed,” it says, “is a coordinated effort to reduce sodium in foods across the board by manufacturers and restaurants — that is, create a level playing field for the food industry.”

And an expert at the University of Cincinnati College of Medicine, Dr. Jane E. Henney, who chaired the committee that produced the IOM report, told Brody that salt should lose its “GRAS” status with the FDA, so that it is no longer considered “safe” as it is currently being used.

By Lois M. Collins, Deseret News