It is known for its sulfur compounds such as allin and allicin. (progressivehealth.com)
I came across this site which has some good information, with regard to vegetables, though not diet as a whole --(i.e.: chop or crush garlic clove and wait 5 to 10 min before consuming or cooking to allow the allin to convert to allicin, the more beneficial compound) (perfecthealthdiet.com)
Well, these supplements rely mostly on garlic's most potent ingredient — allin, which is responsible for the aroma of garlic, but also for most of the plant's health properties. (healthadviceworld.com)