June 7, 2012
The hidden burden of high blood pressure
A condition like high blood pressure is sneaky. You don't feel it, and it generally doesn't cause any outward signs or symptoms. Yet it silently damages blood vessels, the heart, kidneys, and other organs.
High blood pressure — also known as hypertension — isn't a disease. It is a sign that something is wrong in the body. In some people with hypertension, the culprit is a narrowing of the arteries supplying the kidneys (renal artery stenosis), or an overactive thyroid gland (hyperthyroidism) or adrenal glands (aldosteronism). When these are treated, blood pressure drops back to normal. More often, though, doctors find no underlying cause for high blood pressure. This condition is called essential hypertension.
Effects on health
High blood pressure imposes an up-front burden in people who know they have it and who are working to control it. It adds to worries about health. It alters what you eat and how active you are, since a low-sodium diet and exercise are important ways to help keep blood pressure in check. Some people need medication and may need to take one or more pills a day, which can be a costly hassle.
There are long-term consequences, too. High blood pressure contributes to the development of stroke, heart attack, heart failure, and kidney disease. In the United States, it directly accounts for about 60,000 deaths a year and contributes to another 300,000.
Then there are hidden burdens. Perhaps because of all the ways hypertension interferes with health, the average life span for people with it is five years shorter than it is for those with normal blood pressure. A team of Spanish researchers has tallied up another hidden drain of high blood pressure — its effect on survival and rehospitalization after someone is admitted to the hospital for a heart problem.
These researchers looked at the 1,007 men and women admitted to the hospital over a 10-month period for any potentially heart-related problem. These ranged from chest pain and fainting to heart attack, heart failure, atrial fibrillation, and pericarditis. In this group, 69% had been diagnosed with high blood pressure before being admitted to the hospital. Each person was followed for one year. At the end of that time, 17% of those with high blood pressure had died, compared with 9% of those with normal blood pressure. Rehospitalization for a cardiac problem followed the same pattern: 31% of those with high blood pressure, and 18% of those without (American Journal of Cardiology, published online, Aug. 24, 2011).
Keeping the burden at bay
But there is actually good news about high blood pressure: there is a lot a person can to do help keep it in check, and even prevent it from occurring in the first place.
How? The National Heart, Lung, and Blood Institute; the Centers for Disease Control and Prevention; and the American Heart Association offer these recommendations:
- Achieve and maintain a healthy weight for your height.
- Exercise regularly.
- Eat a diet that is rich in fruits, vegetables, and whole grains.
- Limit sodium intake to under 2,300 milligrams a day (one teaspoon of salt), and get plenty of potassium (at least 4,700 mg per day) from fruits and vegetables.
- Drink alcohol in moderation, if at all.
- Reduce stress.
- Monitor your blood pressure regularly, and work with your doctor to keep it in a healthy range.
Why should I limit my dairy intake to one to two servings a day?
Q. The Harvard Healthy Eating Plate, which includes only one to two servings of dairy a day. Don't we need more than that to get enough calcium?
A. Experts at the Harvard School of Public Health created the Healthy Eating Plate to suggest some deficiencies in the U.S. Department of Agriculture's MyPlate, which was released in June 2011 (replacing the familiar food pyramids). Both plates are meant to integrate the latest nutrition advice and serve as at-a-glance aids to planning healthy meals. For example, both convey the important message that fruits and vegetables should make up half your plate at every meal. But the Healthy Eating Plate also directs users to the healthiest choices within each major food group; for example, we recommend eating "whole grains" and "healthy protein" rather than simply "grains" and "protein," as MyPlate does. These distinctions are important. Refined grains like white bread and white rice contain less fiber and fewer nutrients than whole grains, and "protein" could include processed meats, which are not considered healthy.
The Healthy Eating Plate also recommends less dairy than MyPlate—one to two servings a day of milk or the equivalent rather than milk at every meal. One to two servings is enough to satisfy much of our requirement for calcium, and the rest can be obtained from sources such as dark green leafy vegetables and beans (calcium is more highly absorbed from these foods than from milk), tofu, and fortified orange juice and cereals. For example, 500 to 600 mg per day could come from two dairy servings and the rest from these other foods. Dairy can be high in fat and a source of extra calories (even when low-fat milk is used), and if we rely on it to supply most or all of our calcium, we displace healthy plant foods that, unlike dairy, are high in fiber and antioxidants. Dark green leafy vegetables, in particular, are a good source of vitamin K, which is important in bone formation.
The glass included in the Healthy Eating Plate is filled with water, not milk. Milk should be considered a food, not a way to hydrate.
If you follow the Healthy Eating Plate, you'll get calcium from a variety of food sources. But if you think you're not getting enough calcium in your diet, you can add a 500-mg calcium supplement. Also, be sure to get enough vitamin D, which is necessary for the absorption of calcium. You need 800 to 1,000 IU per day. Because it can be difficult to get that much in food, vitamin D may best be taken as a supplement (particularly in the elderly).
— Celeste Robb-Nicholson, M.D.
Editor in Chief, Harvard Women's Health Watch