Don't mindlessly sprinkle salt on your food. A high salt diet leads to hypertension and reduces the effectiveness of BP medication

Not only does a high-salt diet contribute to hypertension, but it can also reduce the effectiveness of blood pressure medications, a new study finds.

“What is striking about these results is the degree of the effect,” said Dr. David A. Calhoun, a professor of medicine at the University of Alabama at Birmingham, and a member of the team reporting the finding in a recent online issue of Hypertension.

Benefits of low-salt diet

The study evaluated 12 people with resistant hypertension, high blood pressure that can't be controlled by a three-drug regimen. Because the study was so small, the results can't be easily applied to everyone with high blood pressure, but “anyone with high blood pressure certainly benefits from a low-salt diet,” Calhoun said.

High blood pressure is a major risk factor for heart attack, stroke and other cardiovascular problems, and heavy salt intake has long been known to contribute to the condition, Calhoun said.

Another study reported in the same issue of the journal described a significant reduction in high blood pressure from a modest reduction in salt intake in a group that included whites, blacks and Asians.

That study, done at St. George's University of London in England, had 169 participants, all of whom had moderately high blood pressure. After reducing their salt intake from 9.7 grams a day to 6.5 grams a day, the average reduction in a six-week period was 4.8 points in systolic pressure and 2.2 points in diastolic pressure.

Both studies emphasise the importance of controlling salt intake to keep blood pressure at safe levels, said Dr. Martha Daviglus, a professor of preventive medicine and medicine at the Northwestern University Feinberg School of Medicine in Chicago and a spokeswoman for the American Heart Association.

Between 20 per cent and 30 per cent of Americans have resistant hypertension, and the emphasis for them has been on drug treatment, Daviglus said. “When a patient comes to a physician's office with hypertension, we start with one drug, then add another,” she said. “We often forget about lifestyle interventions because they are so difficult.”

The two studies show that attention must be paid to both drug treatment and diet, Daviglus said. “They give us some hope that by doing a combination of both, we will be able to reach our goal.”

Most salt comes in processed foods. “It is extremely difficult to avoid high salt intake when you eat these foods,” Calhoun said.

People have to be aware of the salt content of all the food products they buy, Daviglus said. “I always say to them, ‘you have to look at the labels',” she said. “All these foods are loaded with salt, and we don't realise it — even ice cream.” The emphasis should be on eating fresh foods, Daviglus said.