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Ask Dr. Brad

By Brad Lichtenstein, N.D.

Summer 2001

Brad Lichtenstein, N.D.

Question: I know that some people take garlic supplements to decrease their cholesterol. Since being on HAART (highly active antiretroviral therapy), my cholesterol has been high, about 300. Is garlic safe to take with my HIV meds?

Answer: Before we tackle the specifics of your question, let's examine the properties of garlic itself. The active constituents in garlic are alliin and allicin. When garlic is chopped, a chemical reaction occurs, converting alliin to the more pungent allicin. It is the allicin, a sulfur-containing compound, that has strong antibacterial, antifungal, anti-clotting, and lipid-lowering effects. Studies show that both fresh or commercially prepared garlic supplementation lower serum cholesterol and triglycerides, and may prevent absorption of triglycerides after a meal high in animal fat. To get the most benefit from allicin, fresh garlic is superior to commercial preparations, and less expensive. Crush the clove and mix it with a tablespoon of flaxseed or fish oil before swallowing. (These oils contain "healthy" essential fatty acids that reduce blood pressure and serum cholesterol and triglycerides.) Garlic capsules, garlic oils, and garlic extracts that have been dried and converted into "alliaceous oils" also work well. Odor-free commercial garlic formulas are effective if they contain alliin, which will be converted into allicin in the body. Your garlic supplement must contain alliin or allicin to provide a lipid-lowering effect.

The issue of safety is not a simple one. A recent study presented at the 8th Annual Retrovirus Conference examined the issue of garlic supplementation in individuals taking protease inhibitors (PIs). Participants took saquinavir three times a day for 3 days. On day 4, blood levels of saquinavir were measured. From day 5 to day 25, participants took garlic capsules, but not saquinavir. Saquinavir was re-introduced from days 22 to 24. On day 25, saquinavir levels again were measured. After 10 days of neither saquinavir nor garlic (washout period), subjects were again given saquinavir for 3 more days, and blood levels were measured.

The data revealed that six of the nine subjects had a 51% decrease in serum saquinavir levels at day 25. The other three subjects showed decrease after the washout period. As a result of these findings, researchers caution against the use of garlic supplementation when using saquinavir or other PIs. It is important to note that this study was done on a very small number of healthy, non-HIV positive subjects. Saquinavir, the sole PI studied, is already known for its poor absorption, and is never recommended as monotherapy. Finally, three days of saquinavir are not adequate in determining the long-term drug-herb interactions.

Before warning completely against the use of garlic, more studies must be done. However, if you are taking PIs, it might be wise to avoid garlic supplementation, especially in the pill, oil, or extract form, and to focus on other cholesterol-lowering regimens. Since garlic has numerous healing benefits, however, you can continue to use it in food and cooking.

To help control cholesterol levels nutritionally, increase fiber-rich plant foods, decrease saturated fats and cholesterol, consume 48 ounces of water daily, and eliminate coffee and black tea. More damaging than animal food in raising cholesterol, however, is refined sugar, including honey and fruit-sweetened foods and juices. Whole fruit is fine. Lifestyle factors are extremely important. Smoking increases cholesterol, but exercise, both aerobic and resistance training, increases metabolism, inhibits wasting, stimulates the immune system, and helps maintain ideal weight.

Brad Lichtenstein, N.D. is a licensed neuropathic physician in private practice specializing in HIV care, psychotherapy, meditation and yoga therapy. For the past four years, he was the supervising physician for the Immune Wellness Clinic at Bastyr University's Center for Natural Health, a specialty clinic for those living with HIV/AIDS. He can be reached at (206) 545-7133 or

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