Health Benefits of Garlic

Enrich your life by adding garlic supplements


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Garlic is a handy herb to have around during the winter holidays. According to most research to date, not only does it help lower cholesterol, but it also apparently acts as a natural antibiotic, fighting bacteria, fungi, and other microorganisms. Some say garlic is as effective as penicillin, tetracycline, streptomycin, and other prescription medications.

Sounds great, doesn’t it? But with the array of garlic products on the market, not to mention the thriving belief that eating fresh garlic is the only way to obtain its health benefits, consumers may be bewildered when choosing their garlic preparation. Although the jury is still out on which form is best and, indeed, a bit of an industry “garlic war” has ensued, consumers can still make wise choices. To that end, a little background information may be helpful.

A Test of Time, a Body of Research

Ancient Egyptian and Chinese populations used garlic in various ways, such as to fight infection and cure respiratory ­ailments. Greek and Roman healers, including Hippocrates, all believed in its ability to heal. Eighteenth and nineteenth century European physicians explored its healing powers using then-new scientific knowledge and prescribed it in much the same way as their ancient predecessors.

But back then, garlic didn’t come in pills and researchers didn’t use high-tech scientific tools to examine its every particle. Today, however, it’s a different story. More than 2,500 research articles on garlic have been published in the past century, with more than 1,000 of them appearing within the last two decades, according to one author. The focuses of the research are wide-ranging, documenting garlic’s potential not only to fight infection, but also to prevent or delay the four leading causes of death in the United States—heart disease, cancer, respiratory disease, and liver disease.

Not all of the research has been positive, however. One report appearing in the June 1998 issue of the Journal of the American Medical Association put garlic’s ability to impact cholesterol levels in question, although the findings were disputed by many herb experts. They countered that the product used in the study had been shown in previous tests to be less effective than other types of garlic preparations.

Herb-watchers are particularly excited by what the research has to say about garlic’s antibiotic potential. One reason for this is that some pathogenic bacteria are becoming resistant to widely used prescription antibiotics, which are either naturally occurring or synthetically derived. Their strength was that they were developed to attack specific kinds of harmful bacteria. But some bacteria have developed their own ways of resisting attack, so the quest for more naturally occurring, less specifically targeted antibiotics has ensued.

Garlic is emerging as a clear alternative to prescription antibiotics. Research outlines its potential to create an inhospitable environment to a wide range of microorganisms, including at least eight types of antibiotic-resistant bacteria and some fungi, such as Candida, the microbe that causes yeast infections, according to information provided by the nonprofit Herb Research Foundation in Boulder, Colorado. Specifically, garlic extract surpassed penicillin, ampicillin, doxycycline, streptomycin, and cephalexin in fighting eight of nine strains of Staphylococcus, ­Escherichia, and Proteus, according to the foundation. Moreover, like the herb echinacea, garlic may possess the ability to enhance immune function, making the body more resistant to infection, some research shows.

What Makes it Work

Most researchers credit a compound in garlic called allicin for the herb’s healing actions. Tests show that allicin inhibits the enzymes that bacteria need to grow. One early report (it dates to 1952) states that the antibiotic effect of 1 mg of allicin equals the antibiotic effect of 15 IU (10 micrograms) of penicillin.

Allicin is a sulfur compound that is ­created when garlic cloves are crushed, cut, or chewed. Until the clove is broken down, it’s odorless. But once the clove is opened, an amino acid called alliin comes into contact with the garlic enzyme allinase, which quickly transforms alliin into allicin and garlic begins to emit its characteristic odor.

Research shows that if allicin doesn’t make it to the intestines, it won’t do the body any good. Allicin may be destroyed by stomach acids, so in order to get garlic’s full effect, the compound must be protected. That’s why some garlic products are “enteric-coated”—this coat shields the garlic product until it reaches the intestine, where it is broken down and the prepared garlic is released into the body. As for fresh garlic, some say that the herb’s aromatic compounds are easily released from the lungs and respiratory tract, so the benefit can be gained from the fresh herb eaten alone or, more typically, prepared as a food flavoring.

Still other studies indicate that more may be at work than allicin. Researchers have identified about 200 compounds in garlic and have focused primarily on the herb’s sulfur-containing compounds, including S-allyl cysteine, or SAC, and S-allyl mercaptocysteine, or SAMC. Some say these constituents also have a role to play in the herb’s healing potential and shouldn’t be overlooked; moreover, one manufacturer focuses on those two compounds and disagrees that allicin holds any therapeutic potential at all.

Researchers continue to search for the mechanism or mechanisms by which garlic acts to help the human body. Meanwhile, industry insiders are engaged in “garlic wars”—some designing their products to protect allicin, others instead focusing on SAC and SAMC.

A Clove a Day?

Because so much research has concentrated on allicin, many experts say that choosing a product that contains allicin may ensure that you’ll receive the benefits garlic has to offer. Still others acknowledge that more study is needed to determine which garlic form is best—­allicin-packed, or allicin-empty—yet they go further, saying that research may show that each preparation, including fresh cloves, will have advantages that others don’t have.

Until research defines garlic’s best form, perhaps the optimum way to choose your garlic is to read about the suggested benefits and pitfalls of each. And, as always, take note of any cautions particular to your health condition and work with your health-care provider to make sure that garlic is right for you. The dosage box on this page offers a good starting point.