High blood pressure: What you can eat to prevent it

High blood pressure: What you can eat to prevent it

13/03/2010 20:20:00 admin

A new study published in the Lancet and the Lancet Neurology found people with unstable or fluctuating blood pressure with episodes of hypertension were at greater risk for stroke than those who had stable high blood pressure.

Peter Rothwell, a professor of University of Oxford and team evaluated blood pressure in 8,000 people who had a previous heart attack and found patients whose blood pressure varied consistently were six times as likely to suffer stroke as those who had stable high blood pressure.

High blood pressure affects about 1 of 3 adults in the United States. The condition is believed to be a precursor to heart disease and stroke, the first and third leading causes of death in the country.

Below some studies are summarised to give readers some ideas about what they can do to prevent high blood pressure. Stay tuned as we will publish more on the same issue soon.

DASH diet

In 1997, Dr. Emily B. Levitan of Beth Israel Deaconess Medical Center in Boston conducted a study of 36,000 Swedish women aged 48-86 to see how diet affects the risk of high blood pressure or hypertension related heart disease.

They found those with high blood pressure who used the DASH diet, which is full of fresh fruit, vegetables, nuts, fiber, potassium and magnesium, were 37 percent less likely to suffer heart failure.

The National Heart, Lung, and Blood Institute suggests that the diet is so effective because it lowers low density lipoprotein or LDL and homocysteine, two risk factors for both high blood pressure and heart failure.

Garlic

Reinhart KM and colleagues at Hartford Hospital in Hartford, CT published in the Nov 18, 2008 issue of The Annals of pharmacotherapy saying they found eating garlic reduced SBP by 16.3 mm Hg and diastolic blood pressure by 9.3 mmHg compared with placebo in patients with elevated SBP. Use of garlic did not reduce SBP or DBP in patients without elevated SBP.

The anti-hypertensive effect of garlic was confirmed later in March 2009 by Hana Drobiova at Kuwait University and colleagues. They found rats with diabetes and high blood pressure experienced a decrease in serum glucose and systolic blood pressure after three-week treatment with garlic which is high in Allium sativum.

Fructose

Dr. Richard Johnson of the University of Colorado-Denver and colleagues at the Mateo Orfila Hospital in Spain gave 74 men 200 grams of fructose per day in addition to a regular diet for two weeks, and found the subjects increased systolic blood pressure by six millimeters and diastolic blood pressure by about three millimeters.

Americans consume 50 to 70 grams of fructose each day. Fructose is found high in honey, high fructose corn syrup and table sugar.

Vitamin C

Researchers at the University of California Berkeley suggests that high intake of vitamin C may help prevent high blood pressure in young women.

Gladys Block and colleagues examined the association between serum vitamin C levels, which ranged from 0.22 to 3.13 mg/dL, and blood pressure in 242 women aged 18 to 21 of whom two thirds were African-American and the rest Caucasian.

During the 10-year follow-up, the researchers found in young women serum vitamin C levels were inversely associated with both systolic and diastolic blood pressure. The associations were significant even after other risk factors were also considered.

Specially, systolic and diastolic blood pressures in women with the highest serum vitamin C were 4.66 mmHg and 6.04 mmHg lower respectively compared to those with the lowest levels.

Obesity

Paul D. Sorlie, Ph.D and colleagues, authors of the study, from the U.S. National Heart, Lung, and Blood Institute said in their study report in the Nov. 2008 issue of Hypertension that the ever-increasing rate of Americans with high blood pressure may be related to the obesity epidemic and suggested that more prevention effort needs to be invested in preventing obesity.

Mulrow CD and colleagues from Audie L Murphy Memorial Veteran Hospital, Health Sciences Center at San Antonio published a review on the issue in the Cochrane database of systematic reviews (Online). They said that when people lost weight through dieting, they also lowered their blood pressure significantly.

It is not news that weight loss can help lower blood pressure in those who are hypertensive. Many studies linked weight loss and caloric restriction with a decreased incidence of hypertension.

According to the review authors, in 1998, a meta-analysis of data from 12 protective studies including 5 randomized controlled trials found loss of 1 kg of body weight resulted in loss of 2.4 mm Hg systolic and 1.5 mm Hg diastolic blood pressure in obese hypertensive patients.

The current review involved 18 trials that met the reviewers’ criteria for them to examine the association between weight loss dieting and the change in blood pressure in patients with high blood pressure.

The analysis of data from six of the trials of 361 men and women showed that weight loss in the range of 4 to 8 percent of body weight was associated with a decrease of 3 mm Hg systolic and diastolic blood pressure in study subjects.

Data from three trials of 363 participants showed that antihypertensive medications reduced blood pressure by 6 mm HG in systolic and 5 mm Hg in diastolic blood pressure. But people using a weight-losing diet required less intensive antihypertensive drug therapy.

The authors concluded that "Weight-reducing diets in overweight hypertensive persons can affect modest weight loss in the range of 3-9% of body weight and are probably associated with modest blood pressure decreases of roughly 3 mm Hg systolic and diastolic."

Tea

Dr. Diane L. McKay of Tufts University presented a study at the American Heart Association annual conference in Boston in 2009 suggesting that a cup of hibiscus tea a day can significantly lower blood pressure.

McKay tested hibiscus tea in 65 health men and women aged 30 to 70 with blood pressure levels deemed to be a risk for heart disease, heart attack and stroke and found the red, fruity-flavored tea helped lower blood pressure in people with elevated risks of cardiovascular or kidney disease.

Specifically, after treated three times a day for six weeks, participants who were not taking any blood pressure medications experienced on average a 7.2 percent drop in blood pressure compared to 1.3 percent in the placebo group.

Some participants experienced a 13.2 percent reduction in their blood pressure, according to the study authors.

Garden peas

Dr. Rotimi Aluko of the University of Manitoba presented a study at the American Chemical Society’s 237th National Meeting on March 22, 2009 saying that rats treated with enzyme-hydrolyzed protein extract from garden peas for 8 weeks experienced a 20 percent drop in blood pressure and were able to produce 30 percent more urine, bringing their urine levels to normal.

Salt

High salt leads to high blood pressure, which seems to be common sense. But the University of Alabama researchers presented a study at the American Heart Association's Fall Conference of the Council for High Blood Pressure Research, in Atlanta saying that too much dietary salt can contribute to resistant high blood pressure.

In the study, 13 patients with resistant high blood pressure and taking at least three blood pressure medications reduced their systolic blood pressure by 22.6 percent and diastolic blood pressure by 9.2 percent after taking a low salt diet.

A Japanese study presented at the same meeting also showed that high salt diet can exacerbate hypertension via an increase in oxidative stress.

The salt theory is controversial. David A. Freeman University of California - Berkeley and Diana B. Petitti from Kaiser Permanente Southern California published a review saying that studies of many populations show blood pressure goes down as salt intake goes up.

They also say "Experimental evidence suggests that the effect of a large reduction in salt intake on blood pressure is modest, and health consequences remain to be determined."

By David Liu

(This article contains content provided by other writers)

http://www.foodconsumer.org/newsite/Nutrition/high_blood_pressure_i_1303100222.html