4. NUTRITIONAL FACTORS

One of the newer fields of study in aging is nutritional immunology---which examines how foods might influence immune function and inflamm-aging. We tend to focus on the role the gut plays in digestion, but the entire lining of the gastrointestinal tract, as well as the liver, is populated with specialized immune cells, collectively called gut-associated lymphoid tissue (GALT). In fact, by some estimates in other species, upwards of 60 to 70 percent of the immune system is located in the gut. So it would make sense that the nutrients a horse eats, or lacks, might influence the functions of those immune cells. Further, the interaction between the gut microbiota and the immune system is important to consider. Healthy gut microbes may mean a healthy immune system.

Researchers are only just beginning to investigate these links, and some results have been promising.

“We are looking at whether we can improve immune responses to vaccination and modulate the inflammaging responses with nutrition,” says Adams. “We have shown some positive changes---such as our work with probiotics and prebiotics.”

In a couple of studies done in collaboration with Purina Animal Health, administering prebiotics---nutrients that not only have immunomodulatory