Ode to the Odiferous

Call it the ode to the odiferous. More than ever, nutritional researchers are singing the praises of garlic and onions, the so-called odiferous vegetables.

Why? Because these two vegetables seem to be especially equipped with several key cancer-fighting properties.

For example, a large-scale Italian study has revealed a strong association between heavy consumption of onions and garlic and a reduced risk of a range of cancers. The study is based on dietary data garnered from an integrated network of Italian and Swiss case-control studies involving almost 10,000 people with various types of cancer — colorectal, ovarian, prostate, breast, renal cell, esophageal, oral cavity and pharynx cancer. About 15,000 healthy people also were included as control subjects in the study.

Meanwhile, a study conducted by University of Alabama at Birmingham researchers indicated that garlic may increase our body’s supply of hydrogen sulfide, which may safeguard against various types of cancer, including breast, prostate and colon cancer. Researchers also speculate that hydrogen sulfide may also provide some protective benefits to the heart.

For example, hydrogen sulfide injected into mice appeared to prevent damage to the heart muscle caused by a heart attack.

“What they’re finding is that these pungent vegetables appear to be somewhat more effective against certain forms of cancer than some of the other fruits and vegetables,” says Dr. Robert Keith, an Alabama Cooperative Extension System food and nutrition specialist and Auburn University professor of nutrition and food science who has been monitoring the research for several years.

Are the results of these studies cause enough to begin stocking up on garlic and onions? Not exactly, Keith says. The levels of garlic and onions required to derive these fullest health safeguards likely may pose major challenges to Americans and others who consume predominantly western diets.

For example, by some estimates, the amount of garlic required to provide a protective effect may be as much as two cloves a day — not a problem in China and Korea, where garlic plays a preeminent role, but a major problem for most Americans, who consume far less of it.

For most Americans, a far better approach is to explore effective ways to include more garlic and onions in their diets several times a week, Keith says.

However, Keith cautions against investing money in garlic tablets or powders as a convenient way to overcome these challenges. There is little evidence that either of these types of products work as well as the garlic and onions derived directly from diet, he says.

“Do they work as well as the onions and garlic derived directly from diet? Possibly, but we just don’t know at this point,” he says.

As Keith has cautioned time and again, just because researchers think they’ve isolated a particular substance in a fruit or vegetable that provides a particular safeguard doesn’t mean that it’s actually the one.

In many cases, the substances commonly touted as the most effective cancer safeguard may be working with several other chemicals within fruits and vegetables to provide protective effects.

“When you eat garlic or onions, you may be getting this balance, this intricate mix of substances that provides the protective effect,” Keith says. “But in cases where you’re simply isolating only one chemical and putting it into pill form, you may not be deriving the full effects.”

For now, Keith says the best approach, especially for people who have a genuine affinity for onion and garlic, is to find more creative ways to include them in their diet.

And this not only includes onions and garlic but also other odiferous vegetables such as cabbage, another presumed cancer fighter.

Posted by Jim Langcuster at December 14, 2007 01:54 PM