Zinc, an important mineral in human health, appears to affect how the immune system responds to stimulation, especially inflammation, new research from Oregon State University’s College of Public Health and Human Sciences shows.
Zinc deficiency could play a role in chronic diseases such as cardiovascular disease, cancer and diabetes that involve inflammation. Such diseases often show up in older adults, who are more at risk for zinc deficiency.
“When you take away zinc, the cells that control inflammation appear to activate and respond differently; this causes the cells to promote more inflammation,” said Dr. Emily Ho, a professor and director of the Moore Family Center for Whole Grain Foods, Nutrition and Preventive Health in the OSU College of Public Health and Human Sciences, and lead author of the study.
Zinc is an essential micronutrient required for many biological processes, including growth and development, neurological function and immunity. It is naturally found in protein-rich foods such as meat and shellfish, with oysters among the highest in zinc content.
Approximately 12 percent of people in the U.S. do not consume enough zinc in their diets. Of those 65 and older, closer to 40 percent do not consume enough zinc, Dr. Ho said. Older adults tend to eat fewer zinc-rich foods and their bodies do not appear to use or absorb zinc as well, making them highly susceptible to zinc deficiency.
“It’s a double-whammy for older individuals,” said Dr. Ho, who also is a principal investigator with the Linus Pauling Institute.
In the study, researchers set out to better understand the relationship between zinc deficiency and inflammation. They conducted experiments that indicated zinc deficiency induced an increase in inflammatory response in cells. The researchers were able to show, for the first time, that reducing zinc caused improper immune cell activation and dysregulation of a cytokine IL-6, a protein that affects inflammation in the cell, Dr. Ho said.
Researchers also compared zinc levels in living mice, young and old. The older mice had low zinc levels that corresponded with increased chronic inflammation and decreased IL-6 methylation, which is an epigenetic mechanism that cells use to control gene expression. Decreased IL-6 methylation also was found in human immune cells from elderly people, Dr. Ho said.