Chromium is a fascinating enigmatic nutrient. Drs Dattilo and Miguel describe how this essential mineral helps insulin to regulate blood sugar levels and how it affects macronutrient metabolism, keeps triglyceride and cholesterol blood levels in check, and decreases body fat while increasing lean body mass. These capabilities might someday catapult chromium to center stage in the fight against some of America's worst health problems: heart disease, diabetes, and obesity. Recently, for example, the National Institutes of Health established a research program to investigate whether chromium may help to treat type 2 diabetes and impaired glucose tolerance.
However, much about this mineral remains unknown. Dattilo and Miguel explain that scientists have yet to learn the mechanisms by which chromium is transported in the blood and the exact composition of the chromium-containing glucose tolerance factor. Information on the chromium content of foods, as well as the forms in which it occurs (which can affect bioavailability and absorption), is incomplete. Bottom line: there's no Recommended Dietary Allowance (RDA) for chromium, and a person's chromium status can be assessed only by determining if supplemental amounts enhance health.
Our limited knowledge of chromium gives many nutritionists and physicians justifiable pause about recommending supplements of the mineral. However, as Dattilo and Miguel highlight, 8% of American adults take chromium-containing products to help with weight loss, lower blood-sugar levels, and ameliorate other ills. In fact, sales of chromium picolinate are estimated at more than $125 million a year, a significant fraction of the $16 billion dietary-supplement market.
Many Americans believe that they don't or can't get enough chromium from food alone. It's a belief promoted on some of the Web sites that sell supplements or provide selected information about these products. Typically, those sites don't publicize the new Adequate Intakes (AIs) for chromium that were established in 2001 by the Food and Nutrition Board (FNB): 25 [mu]g/day for women and 35 for men. Instead, they continue to highlight the FNB's recommendation back in 1989 of 50-200 [mu]g/day of chromium as the "estimated safe and adequate daily dietary intake" and the Food and Drug Administration's Daily Value of 120 [mu]g/day for use on food and supplement labels.
Of course, these now outdated "recommendations" suggest to many lay people that they should consume at least 50 [mu]g/day of chromium and perhaps 120 [mu]g or more. The Web site for Nutrition 21, the company that developed and markets chromium picolinate as a supplement, goes even further: "The USDA Recommended Daily Intake [sic]...is 120 mcg of chromium per day, while the clinical body of evidence suggests 200-400 mcg for optimal health benefits." The site (http://www.nutrition21. com or http://www.chromax.com) doesn't even mention the new (read "lower") chromium AIs from the FNB.
Some people may indeed benefit by taking extra chromium, and ongoing research will provide the much needed answers. In the meantime, it's counterproductive for parts of the dietary supplement industry and some of the consultants and educators it supports to suggest that supplements of the mineral might be needed by almost everyone. Healthy Americans can meet the current AIs for chromium simply by eating a nutritious and varied diet-and certainly supplementing with a daily multivitamin that provides the mineral.