Boost immunity with sterols: these plant substances help you fight viruses and lower your cholesterol - News and notes: supplement brief

Natural Health, Dec, 2002 by Amanda Lydon

Health claims

Proponents say that sterols boost the immune function of healthy people (who want to prevent colds and other illnesses) and people with diseases (like HIV), and that they also reduce cholesterol.

PLANT STEROLS ARE FAT COMPOUNDS that are structurally similar to blood cholesterol. Soybeans and flaxseeds are especially rich sources. You may know sterols as an ingredient added to some margarines that are designed to lower cholesterol. As a supplement, sterols are usually combined with sterolins, sugar molecules derived from plants. Research on the benefits of sterols and sterolins for immunity was conducted recently.

How It Works

The sterol-sterolin combination stimulates your body to produce additional cells that help your immune system fight off a virus, says Patrick Bouic, Ph.D., head of the immunology department at Stellenbosch University in Cape Town, South Africa, and co-author of The Immune System Cure (Kensington, 1999).

Researchers believe that taking sterols before you eat a meal blocks cholesterol receptors, located mainly in your liver, limiting the amount of dietary cholesterol your body absorbs.

Evidence

A double-blind study published in the International Journal of Sports Medicine in 1999 tested sterol-sterolin supplements on 20 healthy marathon athletes, who typically experience a drop in immune function after a race. Four weeks before a race, half the athletes took a daily supplement containing 30 mg of sterols and 3 mcg of sterolins, while the rest took a placebo. Three days after the race, the white blood cell count of athletes who took the placebo rose by 16 percent, while the supplement group's count rose by only 5 percent. An increase in white blood cells indicates possible infection.

A 2001 study published in Cell Biology International tested a sterol-sterolin combination on 19 HIV-infected patients. The nine subjects treated with the supplement had a higher ratio of virus-fighting cells to immune-suppressing cells than the 10 untreated participants.

A single-blind study published in the European Journal of Clinical Nutrition in December 2001 showed that plant sterols lower total cholesterol when combined with a low-fat diet. In the 12-week study, 22 people were given 2,400 mg of sterols in margarine with their breakfast. Their cholesterol levels fell by an average of 14 percent.

How to Take It

To boost immunity, take a supplement that provides both 20 mg of sterols and 2 mcg of sterolins three times daily on an empty stomach, says James Rouse, N.D., a naturopath in Denver.

To lower cholesterol, Bouic suggests taking 2,000 mg of sterols daily with food. Two tablespoons of sterol-enriched margarine contain 2,200 mg of sterols. Some brands contain heart-harmful trans fatty acids, so choose one that doesn't list hydrogenated oil on the label.

Caveats

Side effects of sterols and sterolins include nausea and dizziness and usually fade after a few weeks. Consult your health care practitioner before taking sterols if you have type 1 diabetes or an autoimmune deficiency.

The Bottom Line

Although the evidence for the immune system benefits of sterols is promising, more studies are needed. Solid research supports its ability to lower cholesterol.