Study Shows Drinking 3 Cups a Day Can Lower Hypertension
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Reviewed By Louise Chang, MD
Nov. 10, 2008 (New Orleans) -- If you're worried about your blood pressure, you may want to follow the British custom of regularly "sipping a cuppa" -- tea, that is.
In a new study, drinking three cups of herbal tea containing hibiscus each day lowered blood pressure.
"Most of the commercial herbal tea blends in the United States contain hibiscus," says Diane L. McKay, PhD, of Tufts University in Boston. She tells WebMD that people with the highest blood pressure at the start of the six-week study benefited the most.
McKay presented the study of 65 healthy men and women with modestly elevated blood pressure at the American Heart Association (AHA) meeting here.
Overall, drinking hibiscus tea blends lowered systolic blood pressure -- the top number in the blood pressure reading -- by an average of 7 points. That was significantly more than the 1-point drop observed in people who were given a placebo in the form of hibiscus-flavored water, McKay says.
While a 7-point drop in blood pressure might not seem like much, she says studies have shown that "even small changes in blood pressure ... when maintained over time ... will reduce the risk of stroke and heart attack."
Past AHA president Robert H. Eckel, MD, says that more study is needed to determine whether herbal tea's blood-pressure-lowering effect can actually be sustained over the long haul.
The degree of blood pressure lowering associated with tea drinking in the study was as much as would be expected with standard blood pressure drugs, he says.
Legumes Help Lower Cholesterol Levels
Other research presented at the meeting suggested that eating a diet rich in pinto beans, chickpeas, and other legumes may help to lower cholesterol levels.
"Based on our findings, [I'd suggest you] consume at least three cups of dry beans and peas, or legumes, a week," says researcher Lydia A. Bazzano, MD, of Tulane University in New Orleans.
Past research has shown that eating soy-rich products may help to control cholesterol levels, but little was known about the non-soy legumes that are more popular in the U.S., she says.
To fill in the knowledge gap, Bazzano and colleagues pooled and analyzed results of 12 studies involving nearly 300 men and women.
Most of them had "undesirable cholesterol levels," she says. Their average total cholesterol level was 250 points at the start of the study; their average LDL, or bad, cholesterol was 172 points.
Total cholesterol in those who ate a legume-rich diet for at least three weeks dropped by an average of 14 points compared to those on placebo. LDL cholesterol dropped by an average of 11 points more in the group eating lots of beans.
High-Fat Diets May Raise Heart Failure Risk
Other research showed that high-fat diets rich in processed meats and cheeses may affect measures of heart failure.
Failing to eat enough vegetables, soy, and fish can have the same effect, says Longjian Liu, MD, of Drexel University School of Public Health in Philadelphia.
Consuming a diet rich in fruits and vegetables, on the other hand, was associated with improved blood vessel function, other research showed.
Eckel shares these tips for a heart-healthy diet:
- Eat fresh, frozen, and canned vegetables and fruits without high-calorie sauces and added salt and sugars.
- Increase fiber intake by eating beans, whole-grain products, fruits, and vegetables.
- Use liquid vegetable oils in place of solid fats.
- Limit beverages and foods high in added sugars. Common forms of added sugars are sucrose, glucose, fructose, maltose, dextrose, corn syrups, concentrated fruit juice, and honey.
- Choose foods made with whole grains. Common forms of whole grains are whole wheat, oats/oatmeal, rye, barley, corn, popcorn, brown rice, wild rice, buckwheat, triticale, bulgur (cracked wheat), millet, quinoa, and sorghum.
- Cut back on pastries and high-calorie bakery products such as muffins and doughnuts.
- Select milk and dairy products that are either fat free or low-fat.
- Incorporate vegetable-based meat substitutes into favorite recipes.
- Encourage the consumption of whole vegetables and fruits in place of juices.
SOURCES: American Heart Association Scientific Session 2008, New Orleans, Nov. 8-12, 2008. Diane L. McKay, PhD, Tufts University, Boston. Lydia A. Bazzano, MD, Tulane University, New Orleans. Longjian Liu, MD, Drexel University School of Public Health, Philadelphia. Robert H. Eckel, MD, former president, American Heart Association.
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