October 4, 1996
Contact: Julie Remington
A number of studies in recent years have reported that beta-carotene supplements increase immune cells in HIV-infected patients. However a recent study by researchers at Oregon Health Sciences University found that beta-carotene supplements did not increase the immune cell counts in patients infected with HIV.
The study led by Gregg O. Coodley, M.D., associate professor of internal medicine at Oregon Health Sciences University, appeared in the journal AIDS in August, 1996. In the study Coodley and his co-authors concluded that supplementation with high doses of beta-carotene is not recommended for HIV-infected patients.
"Though high doses of beta carotene did not harm patients who are positive for HIV, our study showed that beta-carotene did not increase the immune cell counts in a statistically significant way," says Coodley. "Our earlier, 4-week study involving only 21 patients had shown that beta-carotene supplements in HIV-infected patients resulted in increased numbers of important white blood cells, called CD4 cells, that fight infection. However this expanded 3-month study involving 72 HIV-positive patients did not support those results. In this larger study we found no significant difference in the CD4 cell counts or any other immune parameters between the placebo group and the group receiving beta- carotene supplements."
Beta carotene is a natural compound occurring in plants and bacteria that is converted to Vitamin A in the body as needed. A growing literature has suggested that beta-carotene is associated with immune function. A number of epidemiological studies have suggested that low levels of beta-carotene in the blood are associated with an increased frequency of diseases such as lung, stomach, liver and breast cancers as well as coronary artery disease. However large scale intervention studies in which beta-carotene supplements were given to large numbers of patients have yielded mixed results. "Though the whole story on beta carotene and the immune system is not known yet, our larger study failed to demonstrate any benefit from beta-carotene supplementation in HIV-infected people," says Coodley. "Interestingly, these results were not affected whether the patient was in a subgroup that was taking antiretroviral drugs or not."
An HIV-infected person's CD4 cell count is used to track the progression of the disease. The official definition of AIDS is a CD4 count of 200 or less per deciliter of blood measured on two occasions. The normal CD4 count ranges from 800 to 1,200.
"The results of our larger study do not support the use of pharmacological supplementation with high doses of beta-carotene in HIV-infected patients," says Coodley.