Hypertension increases the risk of heart attack, stroke, kidney failure and other diseases. What you eat can be a big part of the problem. This month´s topic for healthy discussion from San Juan Regional Medical Center is...

Blood Pressure: What You Eat Counts

It´s no longer considered cool to say "you are what you eat," but the idea that a good diet will keep you healthy and extend your life is even more valid today than when the phrase was used by 1960s food guru Adelle Davis. For another phrase that has yet to be coined, try: "you are as healthy as your blood pressure." Hypertension, or high blood pressure, affects as many as one third of the world´s adult population, and it increases the risk of heart attack, stroke, kidney failure and congestive heart failure, resulting in more than three million deaths yearly worldwide. Finally, "your blood pressure is dependent on what you eat." If your blood pressure is normal (below 120/80), good eating choices will help you keep it low. And if you´ve already been diagnosed with hypertension, it´s particularly important to follow a blood pressure-healthy diet–low in sodium and fat and rich in fresh fruits and vegetables, whole grains and low-fat dairy products.

SHAKE THE SALT HABIT: Even before medications to treat blood pressure were available, doctors advised patients to lower their salt consumption. And sodium restriction is still an essential part of any blood pressure diet. Excessive salt causes fluid to accumulate in blood vessels and body cells and hinders the kidneys´ ability to eliminate it. It also causes blood vessels to constrict, forcing the heart to work harder to keep blood flowing. The result is hypertension. Individuals vary in their sensitivity to salt, but there´s no question that Americans eat more salt than they need–an average of 4,200 milligrams a day for males and 3,300 for women. The American Heart Association recommends that healthy adults consume no more than 2,300 milligrams of sodium (about a teaspoon of salt) a day and those with high blood pressure, less than 1,500 milligrams. An analysis of two studies from the 1980s and 1990s involving 2,415 subjects found that those who cut back on their sodium intake reduced their risk of dying from heart disease or stroke by as much as 20 percent [British Medical Journal, July, 2007].

Cutting back does not mean simply taking the salt shaker off the table–although that may help–or avoiding salty snacks and foods such as hot dogs, cured meats, pickles and olives. About 70 percent of the sodium in the American diet is hidden in prepared and canned foods, baked goods and restaurant meals. The best way to cut your salt intake is to cook yourself using fresh ingredients. Otherwise, read labels carefully and look for menu items least likely to need salt to boost the flavor profile. Some scientists argue that high blood pressure develops not just in response to an excess of sodium but also because of a deficiency of other minerals such as potassium, magnesium and calcium. Potassium works in conjunction with sodium to regulate fluids. The ideal ratio, according to some experts is 5:1, potassium to sodium (compared to a ratio of 1:2 in the typical American diet). Magnesium is needed to help the body store potassium.

Getting extra potassium and magnesium through supplements is not the answer and, without a doctor´s knowledge, could be dangerous, particularly for persons taking blood pressure medication. Potassium is abundant, however, in fruits and vegetables–apricots, bananas, cantaloupe, carrots, oranges, white and sweet potatoes, apples, beets, watermelon, winter squash and legumes. Magnesium is also to be found in fruits and vegetables, particularly leafy greens, and in whole grains. There are numerous health benefits to be gained from eating plenty of fresh fruits, vegetables and whole grains, even aside from providing these important minerals. Many individuals with high blood pressure also have low levels of calcium, and studies have shown that calcium-rich milk and milk products have a beneficial effect on blood pressure. Since elevated cholesterol is often a factor in the development of high blood pressure, patients are usually told to reduce their intake of saturated fats such as those in meat and full-fat products.

THE DASH DIET: For the Dietary Approaches to Stop Hypertension Study (DASH), scientists at the National Heart, Lung, and Blood Institute put together an eating plan known as the DASH diet. In a study of 459 adults, of which about 27 percent had high blood pressure, this diet was more effective at lowering blood pressure than either the traditional American diet or an eating plan that included traditional foods plus extra quantities of fruits and vegetables. Fruits and vegetables are at the core of the DASH diet, of course. Four to five servings of each are recommended every day (as opposed to the five servings combined recommended by the USDA food pyramid).

The diet also recommends:

six to eight servings a day of grains, the majority of which should be whole grains,
two to three servings of fat-free or low-fat milk and milk products,
six ounces or less of lean meats, poultry and fish and
four to five servings a week of nuts, seeds and legumes.

The DASH diet is flexible, not calling for any specific foods, and it fits into most cultural eating patterns. The Mediterranean diet, with its focus on fresh vegetables, fruits and whole grains, has also been found beneficial to blood pressure.

DASH PLUS LOW SODIUM: In the original DASH study, all subjects were given 3,000 milligrams of sodium daily–much higher than recommended. A second DASH study using the same eating plans looked at the effect of sodium. Subjects were given either 3,300, 2,300 or 1,500 milligrams daily of sodium.

At all three levels of sodium intake, the DASH diet was still the most effective at lowering blood pressure. The greatest reductions, however, were achieved with a combination of the DASH diet plus no more than 1,500 milligrams of sodium. Subjects with hypertension had the biggest reductions but those with pre-hypertension and normal blood pressure also benefited.

Other lifestyle decisions–not smoking, moderate use of alcohol, regular exercise and weight control–are also important ways of controlling blood pressure. Persons diagnosed with hypertension nearly always have to take medication, but a good diet and good lifestyle decisions may reduce the amount of medication needed. It´s crucial to keep your blood pressure low, and what you eat counts.

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