Dr. Mercola

Garlic is one of the most important culinary herbs there is, but it’s also one that’s a proven health tonic. Eating a clove or two of garlic a day really might keep the doctor away, as it benefits health on multiple levels.

It is more accurate to call garlic a vegetable than an herb, and, in fact, it belongs to the allium family of vegetables, along with onions and leeks.

This is where its health benefits begin, because allium vegetables are known for their stink (and garlic is sometimes referred to as “the stinking rose”). That unique scent comes from sulfur-containing compounds, such as allicin, that have many health-promoting effects.

Garlic Fights 160 Diseases, Including Cancer

Studies have demonstrated garlic’s effects for more than 160 different diseases.1 In general, its benefits fall into four main categories:

Reducing inflammation (reduces risk of osteoarthritis and other diseases associated with inflammation)
Boosting immune function (antibacterial, antifungal, antiviral, and antiparasitic properties)
Improving cardiovascular health and circulation (protects against clotting, retards plaque, improves lipids, and reduces blood pressure)
Toxic to 14 kinds of cancer cells (including brain, lung, breast, gastric, and pancreatic)
In terms of cancer, garlic has been shown to kill cancer cells in laboratory studies, as well as shown promise when consumed via your diet. One study showed that women who regularly ate garlic (along with fruits and vegetables) had a 35 percent lower risk of colon cancer.

Those who consume high amounts of raw garlic also appear to have a lower risk of stomach and colorectal cancers.

Furthermore, among people with inoperable forms of colorectal, liver, or pancreatic cancer, taking an extract of aged garlic for six months helped to improve immune function, which suggests it may be useful for helping your immune system during times of stress or illness.

Also worth noting, diallyl sulfide (DAS), a sulfur-containing compound in garlic, has been found to inhibit the formation of carcinogenic heterocyclic amines (HCAs), which form when meat is cooked at high temperatures.

DAS prevents a specific type of HCA from transforming into DNA-damaging compounds by decreasing the production of certain liver enzymes required for this transformation.

What this means is that adding chopped garlic to your burgers, meat loaf, and possibly to your steak via a marinade may help cut down on cancer-causing cooking byproducts.

Immune-Boosting Effects to Fight Infectious Disease (Even Antibiotic-Resistant Bacteria)

Garlic is known for its powerful antibacterial and antiviral properties. It also helps fight infection from yeasts/fungi and worms.

The combination of biochemicals in garlic, including tannins, saponins, phenols, flavonoids, and essential oils, has even been found to fight antibiotic-resistant bacteria. Some of the superbugs killed by garlic were resistant to more than 10 different antibiotics.

Even more intriguing, the garlic used in the study was whole, simply ground with a mortar and pestle, and the researchers recommended adding garlic to your diet as a way to help prevent infections. According to researchers:

“…use of spices (garlic/ginger) in diet can reduce the risk of food contamination, protect the consumer from different foodborne diseases, improve their health status and combat with the foodborne diseases by using small quantity of spices (garlic/ginger) in diet

…it is recommended to use garlic …in different raw forms like pickle, garlic/ginger bread, curry powder, sauces, raw juices and without extensive cooking.

In conclusion, the results of present study have provided the justification for therapeutic potential of spices. The practice of using spices as supplementary or alternative medicine… will not reduce only the clinical burden of drug resistance development but also the side effects and cost of the treatment with allopathic medicine.”

Eating garlic can also help fight off infections from colds and flu. According to one study, those who consumed garlic daily for three months had fewer colds than those who took a placebo.

When they did come down with a cold, the duration of illness was shorter – an average of 4.5 days compared to 5.5 days for the placebo group.

While this may not seem overly impressive, it’s still better than the results achieved by the much-advertised flu drug Tamiflu. If taken within 48 hours of onset of illness, Tamiflu might reduce the duration of flu symptoms by about a day to a day and a half – similar to eating garlic daily.

Antioxidants, Vitamins, and Minerals for a Potent Health Elixir

Like many natural foods, it’s difficult to confine garlic to just one or two benefits, as it appears to offer benefits throughout your body. Garlic is rich in manganese, calcium, phosphorus, selenium, and vitamins B6 and C, so it’s beneficial for your bones as well as your thyroid.

Other health-promoting compounds include oligosaccharides, arginine-rich proteins, selenium, and flavonoids.9 The University of Maryland Medical Center summed up some of its most promising uses:10

“…garlic is used to help prevent heart disease, including atherosclerosis or hardening of the arteries (plaque buildup in the arteries that can block the flow of blood and may lead to heart attack or stroke), high cholesterol, high blood pressure, and to boost the immune system.

Eating garlic regularly may also help protect against cancer.

Garlic is rich in antioxidants. In your body, harmful particles called free radicals build up as you age, and may contribute to heart disease, cancer, and Alzheimer’s disease.

Antioxidants like those found in garlic fight off free radicals, and may reduce or even help prevent some of the damage caused over time.”

Sprouted Garlic Might Be Even Healthier

Have you ever let a head of garlic sit on your counter too long, only to find it had sprouted green shoots? You don’t need to throw it away! Sprouted garlic is not only safe to eat… it may be even healthier than non-sprouted garlic.

In an article published in the Journal of Agricultural and Food Chemistry, garlic sprouted for five days was found to have higher antioxidant activity than fresher, younger bulbs, and it had different metabolites, suggesting it also makes different substances.

Researchers concluded that sprouting your garlic might be a useful way to improve its antioxidant potential. Extracts from this garlic even protected cells in a laboratory dish from certain types of damage.12 This isn’t really surprising when you consider the nutritional changes that typically occur in plants when they sprout.

When seedlings grow into green plants, they make many new compounds, including those that protect the young plant against pathogens. The same thing is likely happening when green shoots grow from old heads of garlic. According to study author Jong-Sang Kim, PhD:

“Plants are very susceptible to attack from bacteria, viruses, and insects during sprouting… This causes them to produce a variety of chemicals called phytoalexins to defend themselves. Most of these are toxic to microorganisms and insects, but beneficial to human health.”

Have You Heard of Fermented Black Garlic?

Black garlic, which is basically fermented garlic, may be even healthier than other forms. In a 2009 mouse study, Japanese researchers found that black garlic was more effective than fresh garlic in reducing the size of tumors, for instance.

The study was published in the journal Medicinal and Aromatic Plant Science and Technology.14 In another study, black garlic was found to have twice the antioxidant levels as fresh—the aging/fermenting process appears to double the antioxidants.

Black garlic is packed with high concentrations of sulfurous compounds, especially one in particular: s-allylcycteine (SAC). Science has shown a number of health benefits from SAC, including inhibition of cholesterol synthesis. Perhaps this is why Mandarin oil painter Choo Keng Kwang experienced a complete reversal of his psoriasis after just four days of eating half a bulb of black garlic a day—this, after trying countless medically prescribed skin creams that were all complete failures.

An advantage of SAC is that it is well-absorbed and much more stable than allicin and 100 percent bioavailable. Researchers are confident it plays a significant role in garlic’s overall health benefits.15 Unfortunately, fermenting garlic is a lengthy process that requires a room with controlled humidity and heat for about a month. Most people don’t have access to such equipment to ferment garlic at home, but you can find it from reliable sources online (in whole bulb form, which tastes surprisingly sweet) or in supplement form.

As an aside, I strongly recommend you include raw garlic in your diet as well, but when you do the fresh clove must be crushed or chopped in order to stimulate the release of an enzyme called alliinase, which in turn catalyzes the formation of allicin. Allicin, in turn, rapidly breaks down to form a number of different organosulfur compounds. So to “activate” garlic’s medicinal properties, compress a fresh clove with a spoon prior to swallowing it, chop it finely to add to a salad, or put it through your juicer to add to your vegetable juice.