Momordica charantia also known as bitter melon or bitter gourd is a climbing vine native to Africa, Asia and Australia that is now cultivated in warm areas all over the world. Bitter melon can help regulate blood sugar, but I've seen no evidence suggesting it curbs sugar cravings. Interestingly, bitter melon is one of the major health herbs in the Okinawan diet, notable because the older people on Okinawa appear to be the healthiest in the world. The island has the highest percentage of centenarians anywhere, the longest disability-free life expectancy, and a very low rate of heart disease. Of course, bitter melon isn't the only explanation for Okinawan health and longevity - diet and other aspects of the island lifestyle play major roles.
Bitter melon is generating a fair amount of scientific interest these days. It is being studied as a treatment for diabetes, AIDS and some types of cancer, although so far there have been no human studies. And while bitter melon has been observed to lower blood sugar, no studies have established a safe and effective dose. In one trial, five grams (about two teaspoons) of powdered bitter melon daily reduced blood sugar by 54 per cent; in another, about a quarter-cup of the extract reduced blood sugar by 20 percent. If you're taking prescription drugs to reduce blood sugar, be sure to tell your physician if you're thinking of trying bitter melon.
As far as HIV is concerned, some research suggests that a component of bitter melon may prevent the virus from infecting human cells, and laboratory studies indicate that one component of the herb may help slow the growth of some cancers. Bitter melon has also been recommended for a variety of other conditions including glaucoma, hemorrhoids, high cholesterol, infertility, psoriasis and stomach cramps, but I've seen no studies demonstrating its effectiveness in treating any of them. In some of the studies that have been done, people taking bitter melon developed headaches. Adverse effects (including headache, fever and stomach pain) were most common among people with glucose-6-phosphate deficiency - an inherited disorder most common among those of Mediterranean or Middle Eastern backgrounds. Expectant mothers should not take bitter melon until we know more about its possible effects in pregnancy.
Andrew Weil, M.D.