Your Brain on Microbes
Chemicals produced by microbes in our intestines may affect the brain. In a study with laboratory mice, Kathy Magnusson and her colleagues have demonstrated that adaptability, short-term memory and learning for long-term memory are related to the microbiome and what we eat. “This suggests that it’s not just about the food itself, but that the food is having an effect on the bacteria that live in our gut, and that can influence our behavior,” says Magnusson, a professor in the OSU College of Veterinary Medicine and the Linus Pauling Institute.
As food moves through the digestive tract, the immune system stands guard against foreign microbes. Interactions between diet and the immune system may also shape our microbiome. Adrian Gombart and his colleagues in the Linus Pauling Institute are investigating this possibility with an emphasis on vitamin D. They have shown that knocking out an antimicrobial gene in immune cells can make animals more susceptible to infection. And they know that vitamin D regulates the same gene. “We’re interested in the cross talk that goes on between diet, the immune system and the microbiome,” says Gombart.
The Zinc Connection
Microbes grab zinc as it passes through the digestive tract, but what happens if there isn’t enough of this micronutrient? Emily Ho is leading studies to understand how zinc-deficient diets change the microbiome and may compromise the immune system. “Our central hypothesis is that age-related alterations in gut microbial composition contribute to age-related deficits in cellular zinc levels and enhanced inflammation,” says Ho, a professor in the College of Public Health and Human Sciences and the Linus Pauling Institute. Ho directs the Moore Family Center for Whole Grain Foods, Nutrition and Preventive Health.
Diet Drives the Microbiome
Changing the microorganisms in your gut requires a shift in diet, but scientists are still learning how such changes affect overall health. Norman Hord and his colleagues in the Moore Family Center are studying the influence of whole grains on microbiome composition. Studies with oats, wheat and other grains are underway to investigate impacts on disease processes such as insulin resistance, a factor in Type 2 diabetes. “When it comes to making health claims about how foods may improve health by changing the microbiome, it’s still the Wild West,” says Hord, co-director of the School of Biological and Population Health Sciences.
Too Much of a Good Thing
Humans need proteins to survive. Most of these critical nutrients are digested in the small intestine, but when some escape into the colon, inflammation can follow. When he arrives at Oregon State in December, David Dallas will continue his studies of microbiome response to proteins in infants, the elderly and people with gut inflammation. “My plan is to develop diagnostics to monitor protein digestion in the gut to guide nourishment in these vulnerable populations,” says Dallas, assistant professor in Public Health and Human Sciences.
Microbes and Diabetes
Among the risk factors for Type 2 diabetes (the most common form of diabetes) are family genetics, obesity, heart disease and lack of exercise. Natalia Shulzhenko (College of Veterinary Medicine) is working with Andriy Morgun and Aleksandra Sikora (College of Pharmacy) to understand how the microbiome might affect metabolism and contribute to the disease. Knowing which microorganisms are associated with it could make it possible to identify the microbial genes at work behind the scenes. The researchers’ long-term goal is to prevent Type 2 diabetes before it takes its toll.
For a deeper discussion of microbiome research, see Gut Check.