Biochemist Gary W. Evans of Bemidji State University in Minnesota gave a special chromium supplement to 10 rats and compared them to 20 rats that received chromium in a form less readily absorbed. After 41 months, he reported Monday at a San Francisco meeting of the American Aging Assn., 80% of the rats that received the supplement were alive, while all others were dead. The rats getting the supplement lived an average of one year longer than the others.
"That's a real departure from the usual life expectancy patterns," said gerontologist Caleb E. Finch of USC. Evans seems to have found "a new and unexpected potential variable in life span that deserves serious consideration in longer-lived species," Finch said.
Previous research has found that the only factor that could produce substantial increases in life span in animals is a significant reduction in caloric intake.
More than 90% of U.S. adults have a dietary deficiency of chromium, in part because it is not readily absorbed from many foods, said biochemist Richard Anderson of the U.S. Department of Agriculture in Beltsville, MD.
USDA researchers have developed and patented a form of chromium, called chromium picolinate, that is more easily absorbed by the body. That is the form used by Evans.
"This could potentially be a major finding," Anderson said, "but whether it is reproducible remains to be established.... There's no reason not to believe it, however."
Because chromium has other beneficial effects as well, Evans said he would "very definitely suggest that people take a multivitamin-multimineral supplement containing chromium picolinate" on a regular basis.
Physiologist Edward Masoro of the University of Texas Health Sciences Center in San Antonio has argued that restricted calorie intake works because it reduces the amount of sugar glucose circulating in the animals' bloodstream a theory that is becoming widely accepted. High levels of glucose damage proteins, a process called glycation, and are responsible for many of the ill effects associated with diabetes.
Masoro and others believe that this accumulation of damaged proteins is one of the major factors that accelerate aging and lead to death.
In addition to the increased life span of the rats fed chromium picolinate, Even as reported that their blood glucose levels were reduced about 25% and that the occurrence of glycated proteins in their blood was reduced about 60% by day 1,000 of the experiment.
Evans concedes that the number of animals in his study was small. "This is basically just a pilot study," he said. But he is hopeful that his preliminary success will allow him to obtain funding for a larger study. Such studies are "very expensive," he added.
Because chromium picolinate acts through its influence on insulin, it has a number of other effects on the body.
"This is not a wonder drug," said the USDA’s Anderson, "but it is certainly something that most everybody could benefit from by having more of it,"
Studies in animals and humans also show that chromium picolinate can help increase lean muscle mass and decrease body fat [when included as part of a comprehensive and healthy weight management program]. When 200 micrograms of chromium picolinate per day was given to some members of the Bemidji football team during the season, while they were lifting weights daily, they had a 22% drop in total body fat, compared to a 1.06% drop for the team members who did not receive it. Those receiving the supplement also had a 42% greater growth in lean muscle mass.
Foods high in chromium include brewer’s yeast, organ meats (especially kidney), oysters and beer. Chromium is also found in the bran and germ portions of grains, but most of it is removed during the refining process–one reason that Americans do not get enough.