Garlic is one of many examples of a centuries-old natural cure that is gaining fresh respect in the new millennium. Aside from its reputation as a vampire repellent, garlic has been used as both food and medicine in many cultures for thousands of years. Garlic is part of the onion family called Alliaceae, which also includes shallots, chives and leeks.
In India, garlic is considered a strong detoxifier while traditional Chinese medicine embraces its ability to expel parasites and ease coughs. In Western countries garlic is gaining significant credibility as a tool for strengthening the immune system. Garlic gets its immune-boosting powers from a compound called allicin which is activated when garlic is chopped, chewed, crushed or cut. (If you cook with garlic it is important to let it stand for 15 minutes after crushing it to allow the allicin to activate fully.)
Holistic practitioners maintain that garlic has a role to play in the prevention of heart disease and stroke as well as lowering LDL (bad) cholesterol and increasing HDL (good) cholesterol. It has been effective in lowering high blood pressure and fighting against bacteria and fungi, including the bacteria that is linked to peptic ulcers. According to studies cited by the National Cancer Institute, garlic’s cell-protecting properties give it the potential to reduce the risk of cancers of the stomach, colon, esophagus, pancreas and breast.
Because it contains vitamins A and C, garlic is considered an excellent treatment for colds and other respiratory illnesses. It acts as a natural decongestant and expectorant and some studies have shown that if garlic is taken at the onset of a cold it can soothe symptoms and shorten the duration by as much as 50 percent.
Garlic Can Boost Immune Function
Garlic contains compounds that help the immune system fight germs. Whole garlic contains a compound called alliin. When garlic is crushed or chewed, this compound turns into allicin (with A, C), the main active ingredient in garlic. Allicin contains sulfur, which gives garlic its distinctive smell and taste. However, allicin is unstable, so it quickly converts to other sulphur-containing compounds thought to give garlic its medicinal properties. These compounds have been shown to boost the disease-fighting response of some types of white blood cells in the body when they encounter viruses, such as the viruses that cause the common cold or flu.
Can Garlic Help Prevent Colds and The Flu?
Garlic has shown promise as a treatment for preventing colds and the flu.
Studies have shown that garlic reduces the risk of becoming sick in the first place, as well as how long you stay sick. It can also reduce the severity of symptoms. One study gave 146 healthy volunteers either garlic supplements or a placebo for three months. The garlic group had a 63% lower risk of getting a cold, and their colds were also 70% shorter.
Another study found that colds were on average 61% shorter for subjects who ate 2.56 grams of aged garlic extract per day, compared to a placebo group. Their colds were also less severe.
If you often get sick with a cold or flu, eating garlic can help reduce your symptoms or prevent your illness entirely.
However, a review of the evidence found that many of the studies investigating the effects of garlic on the common cold were of poor quality.
It’s also unknown if you need to take garlic constantly, or if it also works as a short-term treatment when you start getting sick.
Another easy way to increase your garlic intake is by taking a supplement. However, be cautious, as there are no regulated standards for garlic supplements. That means the allicin content and quality can vary, and so can the health benefits.
Powdered garlic is made from fresh garlic that has been sliced and dried. It does not contain allicin, but is said to have allicin potential. Powdered garlic is processed at low temperatures, and then put inside capsules to protect it from stomach acid. This helps the enzyme alliinase survive the harsh environment of the stomach so that it can convert alliin to the beneficial allicin in the intestine. Unfortunately, it is unclear how much allicin can be derived from powdered garlic supplements. This varies greatly depending on the brand and preparation.
Aged Garlic Extract
When raw garlic has been sliced and stored in 15–20% ethanol for over 1.5 years, it becomes aged garlic extract. This type of supplement does not contain allicin, but it does retain the medical properties of garlic. Many of the studies showing benefits against colds and the flu used aged garlic extract.
Garlic oil is also an effective supplement, and is made by infusing raw garlic into cooking oils. You can add it directly to your meals, or take it in capsules. However, it’s worth noting that animal studies have shown that garlic oil can be toxic to rats at higher doses and in certain conditions. Homemade garlic oil has also been linked with several cases of botulism, so if you’re going to make your own, make sure to use proper preservation methods.
How Much Garlic Should You Eat Per Day?
The minimum effective dose for raw garlic is one segment (clove) eaten two to three times per day. You can also take an aged garlic supplement. In that case, a normal dose is 600 to 1,200 mg per day. High intakes of garlic supplements can be toxic, so don’t exceed the dosage recommendations.