How to maximize the healing effect of garlic

Over 500 papers on garlic have been published since the 1980s. Most have concentrated on the sulphur compounds that form when allicin undergoes certain chemical reactions. Here are some tips on how to maximize the healing effects of garlic.

There is no allicin in fresh garlic; it forms through cooking, cutting or chewing. Ajoene, allyl sulphides, S-allyl cysteine (SAC), and other byproducts have been associated with anticancer, anti-clotting, anti-fungal, antihypertensive, anti­oxidant and cholesterol-lowering effects.

• Some garlic supplements list allicin "content," which is inaccurate because allicin is unstable. "Al­licin yield" or "allicin potential" claims are better, but not by much: manufacturers usually determine "yield" by mixing crushed tablets with water and measuring the allicin released.
• Stomach acid destroys alliinase and stops the release of allicin. So, a supplement is usually coated in gelatine, cellulose or polyacrylic acid derivatives that dissolve only in the intestine.
• There is an allicin-release test that simulates the conditions a garlic supplement encounters as it travels through the digestive tract. Results show that over 80 percent of products tested release less than 15 percent of their claimed allicin potential — way below a therapeutic dosage.
•  Early, heavily-publicized studies suggested a cholesterol-lowering effect, but more sophisticated studies curtailed the initial optimism: researchers were disappointed to find that garlic's cholesterol-reducing potential was minimal, and the same goes for blood pressure.

The good news is that garlic might effect heart disease. "Ajoene," one of the breakdown products of allicin, may reduce heart-attack risk by preventing the formation of blood clots. The situation is more encouraging with respect to cancer, perhaps because most studies investigated raw or cooked garlic instead of supplements.

• A meta analysis showed that averaging six or more cloves a week lowered the risk of colorectal cancer by 30 percent and stomach cancer by 50 percent, compared to consuming less than one clove a week.
• A study of men in Shanghai showed that eating a clove a day reduced risk of prostate cancer by more than 50 percent.

Caveat: consumption of specific foods is determined by questionnaire, and peoples' memories may not be reliable. Furthermore, heavy garlic consumption may just be the hallmark of a mostly vegetarian diet. There is no consensus on how much garlic you need to enjoy its effects or on whether cooked or dried garlic are as good as raw. What is clear: to activate garlic's full power, chop or crush it and let it stand for 10 minutes before cooking.

While many people like to store chopped garlic in oil, this is potentially dangerous if the garlic has not been thoroughly cleaned.

• Minute amounts of adhering soil can harbour Clostri­dium botulinum bacterium, which can cause botulism, a deadly form of food poisoning. This can occur without any evidence of spoilage, so only buy commercial products that contain preservatives like salt or acids.

• While garlic's health benefits are uncertain, its effect on your breath is clear. Eating parsley might help to reduce this unpleasant odour, possibly because of its chlorophyll content.
• Garlic may cause indigestion, especially if eaten raw. Handling raw garlic can be irritating.
• Garlic (both fresh and supplements) may enhance the effects of blood-thinning medications.