There are few foods that can’t be improved with a little garlic. (Ice cream and pecan pie, maybe, but that’s about it.) Its distinctive taste has made it a favorite flavoring for thousands of years…although no doubt the ancient Egyptians and Romans, both of whom used it, also made the first jokes about “garlic breath.”
Nowadays, there are even better reasons than flavor to eat garlic.
Garlic (Allium sativum) is related to the onion (big surprise). It produces bulbs covered with a papery skin. Each bulb can be broken into smaller bulblets, called “cloves.” It’s these cloves that are used for flavoring, either whole or crushed or turned into a garlic extract for use in sauces and dressings.
Ask a traditional herbalist what garlic is good for, and you’ll get a list that would make a snake-oil salesman proud. “Step right up, folks, and buy the cure for everything that ails you–good old garlic. It prevents heart disease. It’s an antibiotic. It stimulates growth. It prevents colds. It’s good for asthma, ear infections, intestinal worms and infectious diseases. It’s a stimulant, a carminative (which means it forces gas out of the intestinal tract, folks, which has got to be good for you, if not for your co-workers), a diuretic, an antiseptic and an insect repellent. It’s also anti-diabetic, anti-bacterial, anti-fungal, anti-yeast and anti-inflammatory!”
Any herb that’s been around as long as garlic has has a similar list of traditional uses attached to it, of course. But guess what? There’s actually some scientific evidence for garlic’s medicinal properties. Specifically, research indicates garlic can reduce the risk of heart attack and stroke and even some kinds of cancer.
A recent study in Toronto is typical: it showed a 12 percent drop in total cholesterol levels among a group of middle-aged people who were given daily garlic capsules. Exactly how garlic accomplishes this is not well understood: not surprising, given the complexity of the chemistry involved.
Before fresh garlic is cut, it contains stable, odorless compounds related to a sulfur-rich amino acid called cysteine. As soon as you cut or crush garlic, however, an enzyme called allinase is released. Allinase converts these odorless compounds, especially one called “alliin,” into new compounds with the typical odor and taste of fresh garlic–especially one called “allicin.”
Allicin is very unstable. In the presence of edible oils–which it almost certainly is, if you’re cooking with it–it reverts into ajoene and dithiins. (“Ajo” is the Spanish word for garlic.) Allicin cooked in water produces another compound, called diallyl disulfide–DADS, for short. These changes are beneficial, because allicin can cause stomach irritation (which is why eating raw garlic isn’t a great idea) and even blister skin.
Ajoenes and dithiins are compounds of sulfur. Ajoenes have shown anticlotting, antitumor and antifungal activity. They also appear to inactivate one of enzymes we use to digest fat, and inhibit the manufacture of triglycerides and cholesterol by the liver. Dithiins have been shown to reduce clotting and act as an antibiotic. DADS has also been shown to have anti-clotting ability.
Some of these compounds also block the formation of certain carcinogens and prevent them from binding to cells. Nitrates, which occur naturally in the environment, turn into nitrites in the body, which can link with other compounds to form carcinogens. In a Penn State study, adding ordinary garlic powder to the diets of rats prevented the formation of these carinogenic compounds.
Of course, the trouble with eating lots of garlic is that you end up with garlic breath. When we digest garlic, sulfur compounds find their way into the bloodstream, and are then exhaled or eliminated in our sweat. The human nose, unfortunately, is extremely sensitive to these compounds–it can detect less them in quantities as small as one part per billion parts of exhaled air. (And since the garlic smell is literally in our blood, mouthwash and toothpaste do nothing to get rid of it.)
Scientists at the University of Innsbruck in Austria recently found that three compounds–allyl methyl sulphide, dimethyl sulphide and acetone–remain in the blood in high levels up to 30 hours after garlic has been eaten. The first two compounds are produced when we digest garlic–but acetone is something quite different: its a chemical produced when fatty compounds such as cholesterol are broken down.
A little garlic breath for lowered cholesterol and a reduced risk of cancer? Sounds like a fair trade to me.
I think I’ll eat Italian tonight.
