Well, what’s wine to boron or boron to wine, or to health?

Both deficiency and excess of boron are injurious to the health and productivity of vines. Either may be caused by injudicious viticultural practices. Deficiency may occur in sandy or highly acidic soils, especially when irrigated freely with water lacking in boron. As the problem progresses, vine leaves are blotched with yellow, shoots swell, and fruit set is impaired, leading to "shot" berries and fruit drop.

Because the range between deficiency and excess is narrow, as appears to be the case in humans, boron toxicity may be brought about by uneven application of borax to prevent or counteract boron deficiency. Toxicity is first manifest by dark speckling of vine leaves. As severity increases, these become confluent, and leaves wrinkle, pucker, and die.

It is, however, boron’s still incompletely defined roles in human health that recently drew my attention.

Boron is one of those trace minerals that gets little of the respect and attention paid to the better-known major nutrients. I’d wager that few people, physicians included, even consider boron a factor in health, nor deficiency a concern, but a nutritional study of six nations revealed that American adults, consuming on average just over 1mg daily, stood last on the list: 7 to 10% less than the British and Egyptians; 32 to 41% less than Germans, Kenyans, and Mexicans. Even so, what harm might be done?

Well, Zuo-Fen Zhang and associates at the UCLA School of Public Health may have found out. Using the huge data bank of National Health and Nutrition Examination Survey (NHANES), which tracks thousands of men and women, Zhang’s group sought correlations between the amount of dietary boron and health effects, beneficial or adverse. They uncovered only one, but it appears dramatic. Prostate cancer lies near the top of the list of deadly afflictions of older men. According to the American Cancer Society, at 198,100 per year, prostate cancer is the most common of new cases of cancer in the United States, more than cancer of the breast or lung or colorectal cancer. Causing 31,500 deaths annually in the United States, prostate cancer is mortally exceeded only by lung, colorectal, and breast cancers. Among the 7,727 older men in the survey, the risk of prostate cancer falls as boron intake climbs. As reported at the conference Experimental Biology 2001 in Orlando, Florida, in early April of this year, the trend was strong: "prostate cancer risk for men eating the most boron, at least 1.8 mg/day was less than a third that of men eating under 0.9 mg/day". Ample boron consumption does not protect against other cancers, nor other chronic diseases, in this study. Zhang called the association "very specific to prostate cancer." This is the kind of exciting discovery that will stimulate plenty of further research.

It’s odd how often something rare or obscure pops up in multiples. At the same conference, Curtis Hunt and Joseph Idso of Grand Forks, North Dakota, working at the Human Nutrition Research Center of the Agriculture Department, reported immune benefits in rats fed boron, estimated to be about equivalent to 2 mg daily in a human diet.

We all know that immune inflammatory reactions are essential to controlling infection. Sometimes, and mysteriously, these reactions become perverted and uncontrolled, attacking one’s own tissues. Such autoimmunity is operative in a number of nasty diseases, including rheumatoid arthritis and systemic lupus erythematosus. The North Dakota aggies’ research showed boron-deficient rats to be more susceptible to autoimmune disorders. Boron is protective, apparently by preventing inappropriate activation of cells (T-suppresser and T-helper) important in autoimmune chain reactions. The group is studying the effect of supplemental boron on the pain of rheumatoid arthritis in humans.

A glass of wine contains about 0.5 mg of boron. A maximum dose of about 2 to 3 mg daily is advised by some to avoid the risk of toxicity. (Charlene Rainey, of Food Research, Inc., of Costa Mesa, California, says that some healthful diets contain 9 to 13 mg per day, and that the safe upper limit is 20 mg daily.) Grapes and other noncitrus fruits and a handful of peanuts each also contains about 0.5 mg, but it seems to me that wine offers the most attractive package. It is likely that Americans’ boron intake is so low because we eat so few fruits and nuts and drink so little wine.

I must close with a warning against taking pure boron supplements. They may lead to toxicity, much less likely from natural sources. Boron poisoning is rare. Its compounds are found in soaps, detergents, fertilizers, wood preservatives, fungicides, high-energy fuels, and in the form of boric acid. Ingestions, absorption from local skin application, and inhalation must provide intense exposure to cause dangerous toxicity in most circumstances. Accidental or suicidal ingestion may be difficult to prevent. Among boron-in-excess’s effects are gastrointestinal disturbances, anemia, convulsions and other brain dysfunction, skin and hair loss, blindness, metabolic imbalance (acidosis), lung impairment, and cardiac arrest.

Boron appears to be an important trace element, if the link to prostate cancer is bourne out by further research. Bear in mind, then, the payoff in boron and antioxidants from consuming ample fruits, nuts, and a moderate quantity of wine.

*In contrast to this demonstration of gentleness, the toxicity of boric acid may be illustrated by the powdered form’s storied lethality to cockroaches when sprinkled about–a cucarachacide.

Dr. Finkel, clinical professor of medicine at Boston University Medical Center, award-winning wine writer, writes and lectures internationally on the influences of wine upon health. He is a member of AIM’’s editorial board.