Antioxidants, Omega-3 Fats to Be Tested in Two Stanford Nutrition Studies.

STANFORD, Calif. -- Area residents who are at risk for heart disease are being sought to participate in two new studies at the Stanford University School of Medicine that will examine whether antioxidants and omega-3 fats help prevent heart disease.

Both studies will be led by Christopher Gardner, PhD, assistant professor of medicine at the Stanford Prevention Research Center.

"Although antioxidants and omega-3 fats are thought to be good for you, there is little agreement among scientists -- and little understanding among the general population -- about how much to take and where to get those nutrients from," Gardner said. "The questions of 'how much' and 'where from' are exactly what we will be studying."

Heart disease remains the No. 1 killer among both men and women, causing more than half a million deaths each year. Risk factors such as high cholesterol, high blood pressure and obesity increase the likelihood of heart disease. Although many people reduce their risk factors by eating healthier foods, exercising more or taking prescription medications, millions also turn to dietary supplements in hopes of staving off heart disease, Gardner said.

Antioxidants are among the more popular supplements. They are food components that are thought to help protect cells against damage, and include such substances as vitamins C and E, the mineral selenium and beta-carotene.

Gardner said recent clinical trials showed that high doses of antioxidants didn't decrease the heart disease risks among the participants. However, those trials used the pill form of the antioxidants rather than foods rich in the substances. Additionally, he said the doses used in the past studies may have been too high.

"The growing popularity of antioxidant supplements underscores the need to determine whether they help protect adults against heart disease," Gardner said.

In the new trial, 90 participants will be randomly assigned to take either a supplement containing a combination of antioxidants or a placebo. Additionally, they will be asked to either consume their usual diet or to modify their diet to include foods naturally high in antioxidants, such as berries, broccoli, tomatoes and nuts.

During the eight-week study, participants will have their blood drawn three times to assess cholesterol and triglyceride levels, as well as the levels of inflammatory markers that Gardner said are emerging as potentially important risk factors of heart disease.

A similar approach will be used in the study of omega-3 fats. Omega-3s are a specific type of polyunsaturated fat found in two main sources: fatty fish (such as wild salmon, sardines and mackerel) and plant food sources (such as flax, walnuts and canola oil). However, Gardner said there is no consensus as to whether plant or marine sources confer similar benefits in protecting against heart disease or what the proper dosage should be.

For the omega-3 fats study, 100 eligible participants will be randomly assigned to take either an omega-3 supplement from a plant or a marine source, or a placebo. The study will last for 12 weeks, and participants will have their blood drawn five times to assess the same risk factors for heart disease being examined in the antioxidant study.

Both studies are funded by the National Institutes of Health.

To be eligible for either study, participants must be at least age 18, in good general health, not taking any lipid-lowering or anti-hypertensive medication, and have certain risk factors for heart disease. Risk factors include high LDL-cholesterol levels, low HDL-cholesterol levels, high triglycerides, high blood pressure or being overweight.

Those interested in participating in the study can fill out an online questionnaire to determine whether they qualify. The questionnaire is available at http://nutrition.stanford.edu/. Participants can enroll in the study anytime during 2007 or in early 2008.

For more information about both studies, contact the project coordinator, Antonella Dewell at [phone].

Stanford University Medical Center integrates research, medical education and patient care at its three institutions -- Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children's Hospital at Stanford. For more information, please visit the Web site of the medical center's Office of Communication & Public Affairs at http://mednews.stanford.edu.