Q. Do I have to avoid salt to lower my blood pressure without medication?

A. Perfect question for Heart Month. Blood pressure is the force exerted on the walls of the arteries by the flow of blood, similar to the flow of water in a garden hose. It's measured by the amount of blood pumped by the heart compared to the resistance of the artery walls. Known as hypertension, high blood pressure increases the risk for stroke, heart attack and kidney failure.

Salt is only part of the blood pressure picture. For those with mild hypertension, other dietary changes can be beneficial. These include increasing food sources of potassium, calcium and magnesium, limiting saturated fat, controlling your weight and limiting alcohol.

Eating lots of fruits, vegetables and low-fat dairy products will provide the body with potassium, calcium and magnesium to help reduce blood pressure.

Limiting animal fats and sugars while increasing whole grains helps prevent plaque from accumulating in the arteries. Excess plaque narrows the arteries increasing the workload of the heart.

These changes can lower blood pressure even when salt is not restricted. However, they have an even greater effect when combined with a lowered sodium intake.

In some people, eating too many salty foods increases the amount of water in the blood. This forces the heart to work harder to pump blood, increasing blood pressure. Potassium blunts sodium's effect by forcing salt to be eliminated in the urine. Since this lowers blood pressure, we should eat twice as much potassium as sodium.

The role of calcium and magnesium is poorly understood; however several studies show that when diets are low in these minerals, blood pressure is high.

Losing excess weight, especially belly fat, improves blood pressure. This is the fat that surrounds our organs. The heart must work harder to supply this extra fat with blood. This extra fat can compress the kidneys. The kidneys respond by releasing hormones that increase blood pressure. Exercise can help reduce belly fat.

Drinking more than two alcoholic drinks daily can raise blood pressure. It also makes hypertension more resistant to treatment. Heavy drinking increases frequency of strokes and heart failure. Limit alcohol to two drinks or less daily for men and one drink or less daily for women.

If diet and exercise do not normalize your blood pressure, medication will be needed. Do whatever it takes to control this "silent killer."

Amy Tousman is a registered dietitian and certified diabetes educator. Hawai'i experts in traditional medicine, naturopathic medicine and diet take turns writing the Prescriptions column. Send questions to: Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; islandlife@honoluluadvertiser.com; or fax 535-8170. This column is not intended to provide medical advice.