Animal Study Shows that Conjugated Linoleic Acid May Offer Protection Against Viral Infections

BACKGROUND: Conjugated linoleic acid (CLA) is a naturally occurring fatty acid found in meat and dairy products. More than 600 scientific papers have been published on the many roles it plays, such as in reducing fat stores and maintaining lean muscle. Some research suggests that CLA may also enhance immune function and resistance to infections.

RESEARCH: Researchers fed 32 pigs either supplemental CLA (at a dosage of
1.33 grams per 100 grams of food) or soybean oil (placebo). After 42 days of supplementation, the animals were infected with "type-2 porcine circovirus (PCV2)". Infection with the PCV2 virus results in wasting, shortness of breath, pallor, and pneumonia.

RESULTS: The animals supplemented with CLA benefited from increased numbers of CD8 T cells, a type of immune cell needed to fight and "clear" viruses from the body. Animals receiving CLA also had less severe cases of pneumonia.

IMPLICATIONS: This study adds to the growing body of evidence suggesting that supplementation with CLA may have a pronounced and positive role in regulating the immune system.

Bassaganya-Riera J, Pogranichniy RM, Jobgen SC, et al. Conjugated linoleic acid ameliorates viral infectivity in a pig model of virally induced immunosuppression," Journal of Nutrition, 2003;133:3204-3214.

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Phytosterols, Known to Lower Cholesterol Levels, Also Function As Antioxidants

BACKGROUND: Phytosterols, also known as plant sterols, are naturally occurring compounds found in all plants, including fruits and vegetables.
Dozens of studies have found that phytosterols, such as those added to some commercial brands of margarine-type spreads, can lower blood levels of cholesterol and, therefore, reduce the risk of coronary heart disease.

RESEARCH: In this study, researchers conducted experiments to determine if phytosterols have antioxidant properties. Antioxidants may also reduce the risk of heart disease. A mixture of phytosterols was compared to the individual three most common plant sterols, beta-sitosterol, stigmasterol, and campesterol.

RESULTS: In these experiments, phytosterols were found to have antioxidant activity against peroxyl radicals, which attack fats, such as those forming cell membranes. The antioxidant activity of the phytosterols was related to their concentration, with a larger amount of phytosterols having a greater antioxidant effect. This antioxidant property was noted in both solutions and cell membranes, which are prone to oxidation.

IMPLICATIONS: This study supports the idea that phytosterols may benefit health through a number of mechanisms. In addition to lowering blood levels of cholesterol (a well known benefit), phytosterols may also protect against free-radical oxidation of cells.

Yoshida Y, Niki E. Antioxidant effects of phytosterol and its components.
Journal of Nutritional Science and Vitaminology, 2003;49:277-280.

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