Garlic - What are the Benefits?

Many people take garlic, either in supplement form, or in their diet, for its health benefits. Garlic is promoted for improved immune system, improved cardiovascular health, and perhaps even cancer prevention. But what does the science say and can it really benefit you? And, if it doesn’t really benefit you, can it actually harm you? These are the questions addressed in this article.

How does garlic work?

Garlic has long been considered a natural remedy for many illnesses, including bacterial, viral and fungal infections. The antibiotic activity of garlic has been associated with its primary active ingredient, thiosulfinate allicin, but there are other active ingredients that have been found to have antibiotic properties, including polysulfides, which have been shown to kill certain cancer cells. Scientists are still trying to understand the exact biological activity of these polysulfides, and many are hopeful that this understanding will help lead to ‘natural’ antiobiotics, fungicides and anticancer agents, with fewer side effects.

What researchers have learned is that garlic has effects on many health conditions, such as high blood lipids, blood pressure and fungal, bacterial and viral infections, to name just a few. The effectiveness is determined by the amount of allicin, which triggers the production of other active constituents. Intact, fresh garlic cells contain an amino acid called alliin, which is actually odorless. However, when the cells are broken, they react with an enzyme, producing allicin, which is the smelly part. The more alliin, the more allicin is produced. The amount of allicin is dependent on the method of preparation. Crushing the garlic increases the allicin, but freeze-drying results in producing very little. Some companies will enterically coat their product to protect the active chemicals from stomach acid. The process to produce odorless garlic extract also reduces the amount of alliin. However, when looking for a garlic supplement, aged garlic extracts usually are standardized to S-allyl-L-cysteine content, which has also been shown to be an effective active ingredient.

What does the science say?

There has been a lot of research into the effectiveness of garlic constituents and how it works. Studies have primarily investigated the effectiveness of fresh garlic, powdered products and aged garlic extracts. Here is some of what has been found:

• For atherosclerosis (hardening and narrowing of the arteries), taking low doses of garlic powder daily, around 300 mg per day, appears to lessen age-related decreases in aortic elasticity. This elasticity is important for keeping the vessels healthy.

• Multiple studies have investigated fresh garlic and various garlic supplements and colorectal and gastric cancer. The overwhelming evidence shows that eating garlic is beneficial, but most studies do not find the same benefit from supplements of any kind. Fresh garlic may also lower the risk of prostate cancer by as much as 50%, but more research is necessary. Garlic in any form doesn’t seem to decrease the risk of breast cancer or lung cancer, however.

• Garlic supplements may help reduce blood pressure by 2% to 7% after 4 weeks.

• Eating high doses of garlic over 20 weeks may actually help reduce the likelihood of tick bites. So, if you plan a hiking trip, start 20 weeks early to ward them off on your trip. However, the amount studied was eating 1200 mg per day, which comes to more garlic than anyone would usually eat.

• It appears that a garlic jell might be as effective as Lamisil for various skin conditions.

• There have been many studies looking at how garlic may help with high blood cholesterol and triglycerides. These studies are very mixed, however. Early studies were showing a positive trend until more modern researcher started looking at these studies and found serious flaws. One analysis of all the studies suggested that there may be short-term benefits on blood lipids after 1-3 months, but no benefit after 6 months. When only the higher-quality studies were examined, the conclusion was that there is no reduction in cholesterol or triglyceride levels.

• For any other condition, research has either shown garlic to not be of any benefit or there is just not enough research to say one way or another.

• Something that studies do consistently seem to show is that often there is no active ingredient in the odorless products.

How should you take it?

Generally, the most effective form of garlic is fresh. Fresh garlic typically contains 1% alliin, where most aged garlic extracts only contain 0.03% alliin. So, for those who like to work with numbers, here are the details:

For every milligram of alliin, 0.458 mg of allicin is typically generated. Therefore, a dose of 4 grams of fresh garlic (approximately 1 clove) containing 1% alliin will produce about 18,300 mcg of allicin. A dose of garlic extract of 600 mg, containing 1.3% alliin will produce 3,600 mcg allicin. So, you decide.

To now answer the question how to take and how much, again, here is what the majority of research has concluded:

- For high blood pressure and high blood lipids, a garlic extract of 600-1200 mg divided up and taken three times a day may be effective, but aged garlic extract of 600 mg to 7.2 grams per day has also been used. Aged garlic extract contains less alliin than the powdered form.

- To prevent stomach or colorectal cancer, fresh or cooked garlic of 3.5 to 29 grams per week is recommended.

- Garlic in the form of the garlic constituent ajoene as a 0.4% cream, a 0.6% gel or a 1% gel has been shown effective for such conditions as tinea infections, warts and corns.

Will it harm you?

In studies, garlic has been used safely for up to 7 years in healthy subjects. For the most part, garlic can be safe, especially as a food ingredient. Just about anyone can take garlic in its food form. Nursing mothers may notice unhappy babies, as garlic can affect the taste of breast milk. Other negative side effects include breath and body odor, mouth and gastrointestinal burning or irritation, heartburn, gas, nausea, vomiting and diarrhea.

The biggest concern with garlic is its effect on bleeding time. Therefore, if you intend to have surgery, discontinue it one to two weeks before surgery. Documentation of garlic’s effect on platelet function is very well-known. As a consequence, anyone taking any medications or herbs that affect bleeding, such as warfarin (Coumadin), fish oil tablets, vitamin E, willow bark, aspirin, Plavix, should discuss this use with their health care professional. Garlic has also been shown to be extremely reactive with antiviral medications.

Garlic a day keeps the doctor away

So, after all of this, what is the basic conclusion? Eat your garlic! Enjoy it in stir fry, raw, cooked, baked, you name it, just enjoy it! If you have a health condition that requires you to take any medications, it’s always best to discuss how garlic will alter the absorbency of that medication. Also remember that herbs are just natural drugs and either discuss them with your doctor or do your research. With a few precautions, however, fresh garlic is an excellent addition to any dish and to a healthy lifestyle.