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Nutrition Research Zooms in on Zinc

Investigations of zinc--an essential nutrient--may yield a new way to test an individual's ability to use this mineral. The diagnostic assay that research geneticist Liping Huang envisions would measure the amount of zinc-related genetic material that an individual produces. Huang is with the Agricultural Research Service’s Western Human Nutrition Research Center at Davis, Calif.

Ideally, the test would require only a small sample of blood, and could be easily administered in a physician's office, according to Huang. In addition, the test would have a fast turn-around, yielding complete results before the patient's brief office visit was over.

Huang is focusing on genetic material called messenger RNA or mRNA. In particular, she’s looking at whether the availability of zinc influences the levels of certain mRNA. The human body uses the information in this mRNA to make what are known as zinc transporter proteins. These proteins shuttle zinc from the foods that we eat into the cells that need it. For example, Huang's work with ZnT4 suggests that this zinc transporter protein aids with storage of zinc in the prostate gland. That might help protect against prostate cancer.

According to Huang, measuring levels of the zinc-transport mRNA is a good approach to assess the amount of zinc transporter proteins. The method most commonly employed today to check body levels of zinc isn't sensitive enough to detect a mild deficiency. In the United States, mild zinc deficiency may exist among otherwise healthy infants, toddlers, preschool children, pregnant and lactating women, and seniors, according to Huang.

In addition to physicians working with individual patients, nutrition researchers interested in the nutrient needs of Americans nationwide could use the test. Findings could help update national dietary guidelines for daily zinc intake--from food or supplements--for different age groups.

Huang's research is described in greater detail in the March 2002 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.