Garlic's benefits come from its sulfur content, which is also is true to an extent of onions. The sulfur compounds in garlic have been showing clinical studies to lower elevated blood lipids, such as cholesterol, provide antioxidant activity and lower elevated blood glucose, which may help prevent diabetes. In addition, garlic has shown anticancer activity in a number of studies, most famously lowering blood pressure. In fact a new study turned up that effect.
How garlic brings down blood pressure is of interest to bodybuilders. Just a few years ago nitric oxide was an obscure substance known only to medical researchers. It gained prominence in the bodybuilding community with the advent of supplements touted to boost its presence in the body. The reasoning: Since one of the primary effects of NO is that it dilates blood vessels, the enhanced blood flow that results will increase the delivery of oxygen and nutrients to working muscle, which will have an ergogenic effect. In addition, NO is involved in the release of anabolic hormones, including testosterone and growth hormone.
Typical NO bodybuilding supplements contain the amino acid L-arginine as their primary ingredient. Arginine is the immediate precursor of NO synthesis in the body. Still, what determines how much NO is produced isn't arginine but rather the activity of enzymes that convert arginine into NO.
In ancient Egypt garlic
was distributed to the
laborers on the pyramids
because it decreased
fatigue and aided recovery.
Human studies with garlic show that it reduces the workload on the heart during exercise and reduces peak heart rate, which points to less heart stress during vigorous exercise. By helping lower high counts of cytokines, immune proteins that increase during exercise, garlic helps lower excess inflammation and speed up and improve exercise recovery.
A more recent study showed that an active ingredient in garlic may even help prevent excess muscle breakdown.2 The research involved isolated-muscle-cell exposure to garlic, specifically an ingredient in aged garlic called daillyl sulfide, or DAS. The cells were exposed to high heat, which results in cell breakdown, but when DAS was added to the muscle cell culture, the breakdown was blocked.
In another part of the study, rats with implanted tumors, who experience cachexia, or the accelerated loss of muscle that occurs in 80 percent of human cancer patients, were given DAS. So was a group of normal rats. While the cancer stricken rats didn't show any effects from the garlic compound, the normal rats had significant increases in muscle. Again, the mechanism was thought to be a blunting of the normal catabolic effects in muscle, which would tip the metabolic scales toward anabolism, or growth. Anabolic steroid drugs produce larger muscles because they provide both anabolic and anticatabolic effects.
While garlic cannot be characterized as a "super muscle growth" supplement, the fact that it helps prevent excess muscle breakdown in normal animals suggests that it may encourage similar effects in bodybuilders when used in conjunction with other anticatabolic supplements, such as whey and casein proteins, HMB and fish oil.
1 Haider,S.,et al.(2008). Repeated administration of fresh garlic increases memory retention in rats.J Med Food 11:675-79
2 Olivan,M.,et al.(2010) Nutraceutical inhibition of muscle proteolysis: A role of diallyl sulphide in the treatment of muscle wasting. Clin Nutr. In press