Tuesday, May 5, 2009

Diet tips for lower blood pressure

Hypertension, stroke, and heart disease are common in the United States and most other Western industrialized nations. Epidemiologists attribute much of their prevalence to diet. After decades of research, scientists have concluded that the typical American diet is a recipe for hypertension and cardiovascular disease: too much salt, too much saturated fat, too many calories, and not enough fruits and vegetables. But the good news is that you can take an active role in preventing and controlling high blood pressure by watching what you eat.

Consume less salt
Doctors first noticed a link between hypertension and sodium chloride — the most common form of dietary salt — in the early 1900s, when they found restricting salt in patients with kidney failure and severe hypertension brought their blood pressures down and improved kidney function.

Federal guidelines advise people to limit sodium intake to 2,300 milligrams (mg) per day — about the amount in 1 teaspoon of table salt. Yet Americans typically consume 1 to 3 teaspoons, or as much as 7,200 mg a day. This fact, coupled with the high prevalence of hypertension in the United States, led researchers to assume that salt overload was the culprit.

As it turns out, this may or may not be true. Nearly 50% of people who have hypertension are salt-sensitive, meaning eating too much sodium clearly elevates their blood pressure and puts them at risk for complications. In addition, people with diabetes, the obese, and older people seem more sensitive to the effects of salt than the general population. However, the question of whether high salt consumption also puts generally healthy people at risk for hypertension is the source of considerable debate. Regardless of whether high salt intake increases blood pressure, it does interfere with the blood pressure–lowering effects of antihypertensive medications.

Keep an eye on fat
A diet low in saturated fat can reduce cholesterol levels, but its effect on blood pressure is not well established. It’s important to remember, though, that not all fats are bad. Particularly heart-healthy are omega-3 fatty acids, which are found in fatty fish like mackerel and salmon, some oils such as canola oil, and some nuts and grains such as flaxseed. Large amounts of these fatty acids may help reduce high blood pressure, but their role in preventing hypertension is unclear. What is apparent is their effect on heart disease. A number of studies have linked modest levels of fish consumption with a reduced risk of heart attack and sudden death.

Boost your potassium intake
Consuming too little potassium can raise your blood pressure and your risk of stroke. Increasing dietary potassium may allow some people to reduce the dose of their blood pressure medication. In a study in Italy, 27 people with hypertension increased their potassium intake while another 27 followed their usual diets. After one year, 81% of people on the high-potassium diet were able to cut their medications by more than half, while only 29% of the people who followed their usual diets could cut back that far.

Before increasing your intake of potassium, check with your doctor. Some people — for example, those with kidney disease — may need to avoid both potassium and salt.

Get enough calcium
Some research suggests a low calcium intake may contribute to high blood pressure, but calcium’s exact role in hypertension is unknown. One theory holds that a lack of calcium in the diet predisposes your body to retain sodium, which raises blood pressure. For this reason, it may be especially important that salt-sensitive people with hypertension get enough calcium.
While there’s evidence that consuming plenty of calcium-rich foods and beverages may help prevent hypertension, efforts to control blood pressure with calcium supplements have had mixed results. At this point, experts are reluctant to recommend calcium supplements solely to lower blood pressure. But since many Americans simply don’t get enough calcium in their diets, and calcium is vital for preventing osteoporosis, few would argue against the use of supplements to boost your calcium intake.

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