Garlic medicine: cures in cloves?

Garlic medicine: Cures in cloves?

For the past four millennia, people have touted the medicinal magic of garlic. From tumor tamer to headache healer, dewormer to aphrodisiac, garlic is deeply rooted in the folk-medicine hall of fame. Now looking beyond the lore, scientists around the world are seriously exploring whether garlic might indeed help bolster human health by defending against heart disease, cancer and a variety of other maladies.

Garlic may drastically inhibit the body's synthesis of cholesterol and blood-clothing agents associated with heart disease, says biochemist Nilofer Qureshi of Advanced Medical Research in Madison, Wis. She and her colleagues fed aged garlic extract and s-allyl cysteine (a sulfur compound derived from garlic) to 60 chickens. After four weeks of daily garlic supplements at doses as high as 8 percent of body weight, the garlic-supplemented chickens showed cholesterol decreases of as much as 30 percent when compared to six chickens receiving no garlic. "More importantly, low-density lipoproteins which transport cholesterol to clog-prone arteries] decreased by up to 50 percent," Qureshi says. Chickens, she notes, synthesize cholesterol much as humans do.

Garlic and other members of the onion genus Allium may also erect a barrier against human cancer, suggests William J. Blot of the National Cancer Institute in Bethesda, Mr. Blot and his colleagues questioned nearly 4,000 people from regions of Italy and China -- including areas with some of the highest rates of stomach cancer in the world -- about their diets for the past 20 years. Those who recalled eating the most Allium vegetables showed the lowest incidence of stomach cancer by as much as 60 percent.

These results come as no surprise to Jos Kleijnen of the University of Limburg in the Netherlands. "Of course people with stomach cancer will eat less garlic," he says. "Garlic upsets the stomach." Kleijnen suggests that the cancer sufferers' current diet -- likely low in garlic -- would naturally bias their memory against dietary garlic in the past. He also questions the accuracy of long-term diet recall, asking, "Do you know what you ate 15 years ago? Do you know what you ate yesterday?"

In a comprehensive review of recent garlic experiments worldwide, commissioned by the Dutch Ministry of Welfare, Public Health and Cultural Affairs, Kleijnen and two colleagues from the University of Limburg addressed the reported effects of garlic supplements on heart disease risk factors. Among the 12 most recent controlled trials in humans, he found serious problems such as small sample size, misleading analyses and patients knowing what treatent they were receiving. And though nearly all the studies showed positive results, he suspects there may be unpublished studies that would shine a less flattering light on garlic.

Kleijnen calls for more garlic studies to measure medicine's bottom line: morbidity and mortality rates. One such report comes from Arun Bordia at Tagore Medical College in Udaipur, India. Bordia tracked 432 heart attack survivors for three years, during which half of the participants consumed the juice from six to 10 cloves of garlic each day. (The average Indian eats one to two cloves, he says.) Many of the others took a garlic-scented placebo. Overall, the garlic eaters suffered 32 percent fewer recurrent heart attacks, and 45 percent fewer deaths from heart attacks, than the unsupplemented patients.

Bordia conceived the idea for his study about 20 years ago after observing an unusual Moslem community in Udaipur. Unlike neighboring groups, the community "had practically no incidence of hypertension, no heart disease, no cancer," he told SCIENCE NEWS. What they did have, he says, was a casual lifestyle and a daily menu of boiled vegetables flavored with melted butter and about 10 cloves of garlic per diner.