Zinc Harder to Absorb in Old Age, Animal Study Shows
THURSDAY, Oct. 11 -- A study in mice has helped researchers identify how zinc deficiencies might develop in older people -- even when they are consuming the recommended levels of this important mineral in their diet.
Zinc deficiency in people can lead to a weakened immune system and increased inflammation associated with a wide range of health problems, including cancer, heart disease, autoimmune disease and diabetes.
The researchers, from Oregon State University in Corvallis, Ore., conducted tests with mice and found that, although their diet contained adequate amounts of zinc, older mice showed signs of zinc deficiency and had a heightened inflammatory response.
When the older mice were given about 10 times their normal dietary requirement for zinc, their signs of inflammation fell to those of younger mice, the researchers reported in the study published online recently in the Journal of Nutritional Biochemistry.
Experts point out, however, that results from animal research are not necessarily applicable to humans.
But the findings suggest that, because the ability to absorb zinc may decline with age, seniors might need to consume more of it to have an adequate dietary intake of this essential mineral.
Up to 2 billion people worldwide, including an estimated 40 percent of elderly Americans, have diets that are deficient in zinc, according to experts.
"The elderly are the fastest-growing population in the U.S. and are highly vulnerable to zinc deficiency," Emily Ho, an associate professor in the university's School of Biological and Population Health Sciences, said in a university news release. "They don't consume enough of this nutrient and don't absorb it very well."
In addition, Ho pointed out that the recommended dietary allowance for zinc is currently the same for older and younger adults, and suggested that this recommendation might need to be reconsidered in light of the fact that seniors may have a decreased ability to absorb the mineral.
"We've previously shown in both animal and human studies that zinc deficiency can cause DNA damage, and this new work shows how it can help lead to systemic inflammation," Ho added.
All senior citizens should take a dietary supplement that includes the full recommended daily allowance for zinc, which is 11 milligrams for men and 8 milligrams for women, Ho recommended. Dietary sources of zinc include seafood and meat.
The U.S. National Institutes of Health Office of Dietary Supplements has more about zinc.
Posted: October 2012
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