Healthy garlic bulbs on a wooden cutting board

The Health Power of Garlic

Garlic, the fragrant, unassuming bulb that plays a role in the flavor of so many dishes, also has a wealth of benefits for your heart, brain and immune system health.

Garlic has a history of at least seven millennia of human use. The ancient Egyptians, who left evidence of this herb behind in their pyramids and tombs, documented its function as a medicine. Garlic's medicinal properties also have been recorded in the medical literature of the ancient Greeks, Chinese and Romans, and in Indian Ayurvedic texts.

In Italy, garlic was tied around the necks of children to ward off colds—although, given its strong scent, it might have also benefitted those who did not yet have the sniffles by preventing transmission. (No one wants to get too close to someone who smells like leftover lasagna!)

Wondering whether there's any science backing up these claims about garlic, which date back to the dawn of early civilization, and span the globe? In fact, research studies have not only validated many of the health benefits historically attributed to garlic, but have also uncovered additional benefits.

The magic of garlic lies in allicin

Woman picking garlic

Fresh garlic is the source of a sulfur-containing compound, known as allicin, that is formed when garlic is crushed, chopped or chewed. Many of the health benefits of garlic can be attributed to allicin, which is also responsible for garlic's pungent scent.

Garlic is truly heart healthy

A couple relaxing on dock after a meal full of healthy garlic

We may be able to thank allicin and its metabolites for garlic's heart health effects. Garlic has been shown in clinical and preclinical studies to reduce platelet aggregation, which can cause blood clots.

That's not the only reason that garlic is a great way to show your heart some love. This herb has also been shown to improve blood pressure and cholesterol levels. In addition, garlic may offer heart-health benefits by reducing coronary artery calcification and C-reactive protein, a marker of inflammation.

Can garlic help fight cancer?

Couple smiling during dinner prepared with healthy garlic

Might garlic help prevent cancer? An older study indicated that in an area of China with high rates of stomach cancer, those with the highest intake of garlic and onions had a 40 percent lower risk of the disease than those with the lowest intake.

A more recent meta-analysis supported this early finding of garlic being linked to reduced risk of gastric cancer, although some data is conflicting. Raw garlic consumption was linked to a lower risk of lung cancer and liver cancer in two studies of Chinese populations. Impressively, an analysis of nine epidemiological studies found a 23 percent reduction in the risk of prostate cancer in association with high garlic intake.

Bioactive compounds from garlic, including S-allyl mercaptocysteine and S-allylcysteine, have been shown to inhibit the proliferation of various cancer cells. These compounds may work by inducing cell cycle arrest and cell death in cancer cells.

Why garlic is good for the long haul

Man on healthy garlic diet using a loptop computer

Some scientific research has linked garlic consumption to better cognitive health—and a longer life. Aged garlic extract may have neuroprotective effects against the toxicity caused by amyloid-beta, suggesting that garlic compounds have potential in the fight against Alzheimer's disease.

And an exciting study in roundworms has shown that garlic extract extended their lifespan by 20 percent, suggesting its candidacy for further life extending research. In older people, frequent or occasional garlic consumption was linked to a lower risk of all-cause mortality compared with those who rarely had garlic.

Garlic benefits your immune system

One factor that might contribute to that lower mortality is research that shows garlic can boost the human immune system. A randomized, double-blind, placebo-controlled study conducted during flu season found that subjects taking aged garlic extract had reduced cold and flu severity with fewer symptoms and had a lower number of school and work absences.

Garlic also has been shown to have antibiotic properties. Preclinical studies comparing garlic to broad-spectrum commercial antibiotics have sometimes shown it to be the more effective of the two, or that it improves the efficacy of the antibiotic. And interestingly, garlic may help to prevent bacteria from developing resistance to treatment.

How to make sure you’re eating enough garlic

Woman examining string of garlic bulbs

Now that you know about garlic's goodness, how can you make sure you're eating enough of it? Raw garlic can be chopped and added to a number of foods, or placed in empty capsules and swallowed.

A journal article from over 30 years ago titled "Garlic revisited: therapeutic for the major diseases of our times?" predicted that "Garlic may play an invaluable role in the prevention and therapy of the major causes of death," and they may not have been far off! So adding garlic to your diet in some form may pay off in the long run.

As the research shows, despite its stinky reputation, garlic still comes up smelling like a rose when it comes to health.

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By: Dayna Dye, Certified Medical Assistant

Dayna Dye is a certified medical assistant and the author of thousands of articles published during the past two decades about health, nutrition, aging and longevity. She has been interviewed on radio and TV and in newsprint. She is currently a member of Life Extension's Education Department.

Scientifically Reviewed By: Michael A. Smith, MD