Nuts And Oats May Build A Strong Heart

November 09, 1998

DALLAS, Nov. 10 -- Heart-healthy components in oats may help lower high cholesterol levels and a nutrient in nuts may help prevent death from heart disease, according to preliminary research from two studies presented today at the American Heart Association's 71st Scientific Sessions.

In a 12-year study of 22,071 doctors participating in the Physicians Health Study, men whose diets contained high quantities of nuts had a decreased risk of dying from heart disease, says the study's lead author Christine M. Albert, M.D., an instructor at the Harvard Medical School in Boston.

Albert's team notes that nuts contain unsaturated fats including alpha-linolenic acid, which may help prevent fatal disturbances in the heart's rhythm.

In a study funded by Quaker Oats at Tufts University in Boston, another group of researchers examined 43 men and women eating a diet rich in oats. People on the diet had lower blood pressure and reduced blood levels of cholesterol at the end of the study. High blood pressure and high cholesterol are risk factors for heart attack and stroke.

The oat diet lowered total blood levels of cholesterol by 34 milligrams per deciliter (mg/dL), while study participants who ate a diet that substituted wheat for oats lowered their cholesterol only 13 mg/dL. The individuals' blood levels of low-density lipoprotein cholesterol (LDL or "bad" cholesterol) -- which can accumulate in blood vessels, increasing risk of a heart attack or stroke -- followed the same pattern: The oat group's LDL was 23 mg/dL lower and the wheat group's LDL was 8 mg/dL lower.

Also, the people in the oat group reduced their systolic (top number) blood pressure by 7 millimeters of mercury (mm/Hg) at the end of the six-week study compared to 2 mm/Hg for the wheat group.

"Blood pressure lowering is generally a good thing for the population. The question here is: if this dietary intervention works to reduce normal blood pressure, can we also use the same method to reduce high blood pressure?" says lead author of the oat study, Edward Saltzman, M.D., of the Energy Metabolism Laboratory at the USDA Human Nutrition Research Center on Aging at Tufts University in Boston.

Saltzman attributes the benefits of oats to its soluble fiber -- the type of dietary fiber that dissolves in water. "There are several reasons why foods such as oats that contain soluble fiber, or soluble fiber itself, could have beneficial effects on blood pressure or cholesterol. The presence of soluble fiber in foods slows the rate of digestion and absorption."

The slower digestion causes a more gradual rise in insulin levels. Insulin is a hormone that helps regulate blood sugar, but it may raise blood pressure in some individuals. "There may be other as yet unidentified factors in oats that affect the way the blood vessels react," says Saltzman.

The men and women in the study ate one of two calorie-controlled diets. Researchers determined each individual's maintenance caloric needs then gave them each 1,000 calories less than each person's maintenance level each day. The study group was given an oat-rich diet. The control group -- used as a comparison standard -- ate a diet that substituted wheat for oats.

The two diets differed mainly in the amount of soluble fiber. Oats contain more of this fiber than the same quantity of wheat. Other foods high in soluble fiber are barley, lentils, pinto beans, black beans and citrus fruits.

Saltzman stressed that his study was very preliminary and more research is needed to determine if an oat-rich diet would have the same effects in a long-term study. He says the diet needs to be strictly followed for results to be significant. "It's a hard thing to feed people for six weeks, but it's really hard to get them to follow a diet at home for a year or two," he says.

In the Harvard investigation linking nut consumption to a reduced risk of heart disease, Albert says alpha-linolenic acid, a component of nuts, may protect the heart by preventing a rhythm disturbance called ventricular fibrillation that causes sudden death. When the heart lapses into ventricular fibrillation, it cannot pump blood unless shocked into a normal rhythm with an electrical device called a defibrillator. Albert says previous studies in animals have hinted at this link as well.

Other sources of alpha-linolenic acid are unhydrogenated canola and soybean oils used in most full-fat commercial salad dressings, flaxseed and flaxseed oil and a leafy vegetable called smooth purslane which is eaten mainly in Greece. Albert stressed that her results are preliminary because the questionnaires asked only whether the physicians had eaten nuts, not what kind or how many they ate. Also, other factors of diet or risk factors for heart disease might skew the results. "Most nuts are also high in other unsaturated fats and nutrients that might contribute to reduced heart disease risk," says Albert. However, some nuts -- like Brazil nuts -- are high in saturated fats as well. Consumers need to be aware that all nuts are high in total fat and calories.

However, those questioned who ate the highest amount of nuts had the lowest risk for any heart-related death -- even after adjusting for age, exercise habits, high blood pressure, cholesterol levels, diabetes, alcohol use, other dietary habits and whether individuals were being treated for heart disease.

Saltzman's co-authors are Sal K. Das, M.A.; Andrew S. Greenberg, M.D.; Gerard E. Dallal, Ph.D.; Ernst J. Schaefer, M.D.; Susan B. Roberts, Ph.D.; and Alice H. Lichtenstein, Ph.D.

Albert's co-authors are JoAnn E. Manson, M.D.; Walter C. Willett, M.D.; and Charles H. Hennekens, M.D. Albert's study was funded by the National Institutes of Health.

Media Advisory: Dr. Albert can be reached by phone at (617) 732-4965 x8784; or by fax at (617) 731-3843. Dr. Saltzman can be reached by phone at (617) 556-3245; or by fax at (617) 556-3344. (Please do not publish numbers.)
-end-


American Heart Association

Related Heart Disease Articles from Brightsurf:

Cellular pathway of genetic heart disease similar to neurodegenerative disease
Research on a genetic heart disease has uncovered a new and unexpected mechanism for heart failure.

Mechanism linking gum disease to heart disease, other inflammatory conditions discovered
The link between periodontal (gum) disease and other inflammatory conditions such as heart disease and diabetes has long been established, but the mechanism behind that association has, until now, remained a mystery.

New 'atlas' of human heart cells first step toward precision treatments for heart disease
Scientists have for the first time documented all of the different cell types and genes expressed in the healthy human heart, in research published in the journal Nature.

With a heavy heart: How men and women develop heart disease differently
A new study by researchers from McGill University has uncovered that minerals causing aortic heart valve blockage in men and women are different, a discovery that could change how heart disease is diagnosed and treated.

Heart-healthy diets are naturally low in dietary cholesterol and can help to reduce the risk of heart disease and stroke
Eating a heart-healthy dietary pattern rich in vegetables, fruits, whole grains, low-fat dairy products, poultry, fish, legumes, vegetable oils and nuts, which is also limits salt, red and processed meats, refined-carbohydrates and added sugars, is relatively low in dietary cholesterol and supports healthy levels of artery-clogging LDL cholesterol.

Pacemakers can improve heart function in patients with chemotherapy-induced heart disease
Research has shown that treating chemotherapy-induced cardiomyopathy with commercially available cardiac resynchronization therapy (CRT) delivered through a surgically implanted defibrillator or pacemaker can significantly improve patient outcomes.

Arsenic in drinking water may change heart structure raising risk of heart disease
Drinking water that is contaminated with arsenic may lead to thickening of the heart's main pumping chamber in young adults, according to a new study by researchers at Columbia University Mailman School of Public Health.

New health calculator can help predict heart disease risk, estimate heart age
A new online health calculator can help people determine their risk of heart disease, as well as their heart age, accounting for sociodemographic factors such as ethnicity, sense of belonging and education, as well as health status and lifestyle behaviors.

Wide variation in rate of death between VA hospitals for patients with heart disease, heart failure
Death rates for veterans with ischemic heart disease and chronic heart failure varied widely across the Veterans Affairs (VA) health care system from 2010 to 2014, which could suggest differences in the quality of cardiovascular health care provided by VA medical centers.

Heart failure: The Alzheimer's disease of the heart?
Similar to how protein clumps build up in the brain in people with some neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, protein clumps appear to accumulate in the diseased hearts of mice and people with heart failure, according to a team led by Johns Hopkins University researchers.

Read More: Heart Disease News and Heart Disease Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.