IT MAY not have the most pleasant after-taste, and it leaves a lingering odour that can be repulsive, but garlic supplements have fast become another staple of natural health buffs. Manufacturers and marketers say the capsules have been proven effective in minimising the risk of cardiovascular disease and are beneficial in maintaining good health. But while Hongkong has more than its share of believers in herbal and natural treatments, academics and nutritionists say the claims made by garlic supplement manufacturers are dubious at best, and while it may not be harmful, it is probably not helpful either. ''Based on herbal medicine theories, garlic is said to be a good food,'' said Ms Mimi Sham, president of the Hongkong Nutrition Association. ''But from a Western nutrition point of view, we only view garlic as a normal food item, and we certainly don't think it has any miraculous functions. ''It is just like eating cabbage or broccoli.'' The quantity of garlic consumed as a food was so minute it was virtually inconsequential, she said. ''Garlic supplements are more of a gimmick than anything else. People who market them want to single out a particular nutrient and credit it with all kinds of functions and effects,'' Ms Sham said. ''But it has no such effects that we know of. In the medical world we have not found any evidence to support these claims.'' She said garlic supplements - like other treatments - should be subjected to medical scrutiny before healing claims can be made. Dr Kwan Chiu-yin, head of the department of physiology at the University of Hongkong, said certain chemical compounds within garlic were said to affect the cardiovascular system and helped prevent clotting of platelets, small colourless discs of protoplasm in the blood. ''Garlic is especially popular in North America, as many people believe that if they take it regularly it can prevent clogging and blocking of major arteries, guarding against heart attacks,'' Dr Kwan said. He said garlic was more widely acceptable than ginseng, and was often used for health-related reasons in the United States and Europe. But whether or not garlic performed any of these functions remained to be seen. ''Garlic is considered one of those things that is favoured by people who are into healthy food and natural intervention without drugs. But whether it is clinically useful is a matter for debate. ''If garlic pills really do what they claim to, this can still not be proven clinically. People don't generally eat a lot of it anyway, but even if they do they probably can't do any harm.''