Heart Care, September 2006

Low-Fat Dairy Products May Fight High Blood Pressure

Eating dairy products, especially low-fat ones, could help lower your blood pressure, according to a report in the medical journal Hypertension.

Scientists are not clear where the beneficial effect comes from, but they say low-fat dairy might be a crucial component of a healthy diet.

"If you like to eat dairy products, you may be better off watching the fat content," says Dr. Luc Djousse at Brigham and Women's Hospital. "Low-fat dairy products may be better than full dairy products, where the saturated fat especially is high.”

For the new study, the investigators looked at a possible link between dairy consumption and blood pressure among 4,797 participants of the Family Heart Study, sponsored by the National Heart, Lung, and Blood Institute (NHLBI).

High Dairy Intake Works, Low-Fat a Must

The researchers divided participants into four groups based on the amount of dairy consumed.

Those consuming the most dairy products said they ate more than three servings per day, while those consuming the least averaged less than half a serving per day. Dairy included cheese, yogurt, and milk.

Systolic blood pressure was 2.6 millimeters of mercury (mm Hg) lower, on average, for people eating the highest amount of dairy, compared with those eating the least amount of dairy.

Systolic blood pressure is the first (higher) number in a blood-pressure reading, and it indicates the pressure in the arteries when the heart beats.

But when saturated fat content was taken into account, the beneficial effect on blood pressure was only seen among those who ate lower amounts of saturated fat.

In this group, participants who ate the most dairy had a systolic blood pressure that was 3.5 mm Hg lower than those who ate the least dairy.

Among participants who ate lower amounts of saturated fat, those who also ate the most dairy had 54 percent lower odds of high blood pressure than those eating the least amount of dairy.

The study was not able to identify those people who ate low-fat dairy, but it had data on total fat, polyunsaturated fat, and saturated fat.

Samantha Heller, nutritionist at New York University Medical Center says: "The association [in the study] was mainly among people with less saturated fat. We know this is a bad fat, and [you should] eat as little as possible."

Fruits and Veggies Add Extra Help

About one in three Americans suffers from high blood pressure, which is a major risk factor for stroke and heart attack as well as kidney and heart failure.

Medications can treat the condition, as can lifestyle changes such as diet.

The Dietary Approaches to Stop Hypertension (DASH)  diet, which is low in salt and rich in fruits, vegetables, and low-fat dairy products, has been shown to significantly lower blood pressure.

But the secrets to the success of the DASH diet have remained elusive.

"There was such a combination of factors that we don't know whether the effect of DASH  came from low sodium, low cholesterol, or fruit and vegetables," explains Dr. Djousse. "It has been hard to tell which part of that, or a combination of all, that were producing the effects.”

It is not clear where the benefit is coming from or even if it is cause-and-effect. It is unlikely to be calcium, Dr. Djousse says, although potassium and magnesium, which are also plentiful in the DASH  diet, might be responsible.

"Our study showed that dietary potassium and magnesium were associated with lower odds of high blood pressure," says Dr. Djousse.

The bottom line? "It would help to eat dairy products as long as you keep the saturated fats in check," explains Dr. Djousse.

Always consult your physician for more information.

Online Resources

(These links are provided for the education and convenience of our Neighbors. AAMC is not responsible for the content of Internet sites.)

American College of Cardiology

American Heart Association

Centers for Disease Control and Prevention (CDC)

Choose To Move, AHA

DASH Eating Plan

Go Red for Women Campaign, AHA

Hypertension

MyPyramid.Gov

National Heart, Lung, and Blood Institute (NHLBI)

National Institutes of Health (NIH)

National Library of Medicine

US Department of Health and Human Services (HHS)

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Healthy Diet Planning

The food guide pyramid is a guideline to help you eat a healthy diet.

The food guide pyramid can help you eat a variety of foods while encouraging the right amount of calories and fat.

The US Department of Agriculture (USDA) and the US Department of Health and Human Services (HHS) have prepared the following food pyramid to guide you in selecting foods.

The pyramid is divided into six colored bands representing the five food groups plus oils.

Orange represents grains: Make half the grains consumed each day whole grains. Whole-grain foods include oatmeal, whole-wheat flour, whole cornmeal, brown rice, and whole-wheat bread.

Check the food label on processed foods - the words “whole” or “whole grain” should be listed before the specific grain in the product.

Green represents vegetables: Vary your vegetables. Choose a variety of vegetables, including dark green- and orange-colored kinds, legumes (peas and beans), starchy vegetables, and other vegetables.

Red represents fruits: Focus on fruits. Any fruit or 100 percent fruit juice counts as part of the fruit group. Fruits may be fresh, canned, frozen, or dried, and may be whole, cut-up, or pureed.

Yellow represents oils: Know the limits on fats, sugars, and salt (sodium). Make most of your fat sources from fish, nuts, and vegetable oils.

Limit solid fats like butter, stick margarine, shortening, and lard, as well as foods that contain these.

Blue represents milk: Get your calcium-rich foods. Milk and milk products contain calcium and vitamin D, both important ingredients in building and maintaining bone tissue.

Purple represents meat and beans: Go lean on protein. Choose low fat or lean meats and poultry. Vary your protein routine - choose more fish, nuts, seeds, peas, and beans.

Activity is also represented on the pyramid by the steps and the person climbing them, as a reminder of the importance of daily physical activity.

Always consult your physician for more information.