Trillions of tiny aliens have staked out a home both on and inside your body. But in most cases, their occupancy isn’t an invasion. Rather, these colonies play an essential role in helping keep your body healthy.

These microorganisms collectively make up an ecosystem known as the microbiome, and their well-being is intimately intertwined with our own. In the gut, microbes help regulate digestive health by processing essential vitamins and minerals and by fueling our metabolism.

Now, new Cornell research shows that biofortified foods — bred to have higher levels of micronutrients — can improve the overall composition and function of gut bacteria, which in turn provide health benefits for their host’s body. The paper, “Effects of Iron and Zinc Biofortified Foods on Gut Microbiota In Vivo (Gallus gallus): A Systematic Review,” published in the journal Nutrients on Jan. 9.

“Our analysis indicated that the dietary inclusion of approximately 50% of iron/zinc biofortified foods has a significant beneficial effect on the gut microbiota,” said Elad Tako, associate professor of food science in the College of Agriculture and Life Sciences and corresponding author on the study. “With added improvements in intestinal functionality, this also indicates that feeding a healthy microbiome reduces the risk of metabolic and chronic diseases.”

This review is the first study to examine the direct link between biofortified foods and gut microbiota. The researchers looked at the effects of iron-biofortified wheat and beans, and zinc-biofortified wheat using an in vivo model (Gallus gallus).

In five comparable studies, Tako said they noticed a decrease in potentially pathogenic gut bacteria and an increase in bacteria populations that produce short-chain fatty acids (SCFA) — both of which could be attributed to the biofortified foods.

SCFAs are the main energy source for cells lining the colon. Higher levels of these fatty acids help fuel metabolism and lead to greater uptake of dietary minerals, like iron and zinc.

Sometimes referred to as “hidden hunger,” mineral deficiencies are present in populations experiencing both undernutrition and overnutrition. Around the world, iron deficiencies affect approximately 2.3 billion people, and zinc deficiencies affect another 1.3 billion — leading to poor growth, depressed immune function, physical birth defects and neurobehavioral abnormalities.

“Our review indicates that consumption of iron/zinc biofortified foods is an effective and sustainable approach to reduce the double burden of malnutrition,” Tako said.

The group’s analysis demonstrated that iron and zinc biofortified foods improved the overall health profile of beneficial gut bacteria. The increase in mineral absorption supported a more robust population of these beneficial microbes and lowered the overall risk for measles, influenza A, Hepatitis B and bladder cancer.

This evidence of a direct connection between the consumption of biofortified foods and the improved profile of gut bacteria, supports other areas of ongoing research that investigate more ways in which the microbiome affects our overall health.

This review is part of a special issue of Nutrients, “Alleviating Zinc Dietary Deficiency, and Monitoring Poor Physiological Zinc Status in Sensitive Populations.”

Co-authors are Mariana Juste Contin Gomes, a Fulbright scholar in the Tako Lab, and Hércia Stampini Duarte Martino, a visiting professor in the Tako Lab. Both are also part of the Department of Nutrition and Health at the Federal University of Viçosa in Brazil.

This article also appears in the CALS Newsroom.

Jana Wiegand is the editorial content manager for the College of Agriculture and Life Sciences.