The classic fairy tale Goldilocks and the Three Bears showcases a bedrock principle of pharmacology. The beneficial effect of drugs often is dose-dependent. One dose is not enough. Another is too much. Yet another dose is just right. Shela Gorinstein and colleagues in Israel and Poland have discovered that the Goldilocks rule prevails for garlic. Past scientific studies suggest that garlic is good for the heart. Garlic lowers total cholesterol levels, for instance, and levels of LDL ("bad") cholesterol. It also makes the blood less likely to clot. In experiments with laboratory rats, Gorinstein and colleagues have shown that garlic's effects on total cholesterol are dose-dependent. Lab rats on a high-cholesterol diet got varying amounts of raw garlic each day -- ranging from 500 milligrams (mg) to 1,000 mg per kilogram of body weight. Their report is scheduled for publication in the June 14 issue of the Journal of Agricultural & Food Chemistry.
Only the 500 mg dosage lowered cholesterol and had a beneficial effect on blood clotting. Although the results cannot automatically be applied to humans, the dose was equivalent to about 1.25 ounces of raw garlic per day for a 150-pound person. That amounts to a mega dose of fresh garlic -- about a dozen cloves a day.