Obesity and type 2 diabetes mellitus (T2DM) are complex chronic diseases with rapidly growing prevalence across the world. Human studies have found that both genetic and environmental factors contribute to T2DM; the clearest lifestyle factors are high caloric intake and low physical activity. The mechanisms by which human T2DM arises is still unclear, but obesity, insulin resistance and ß-cell dysfunction all play a role.

The higher rates of colon cancer in Americans of African origin compared to South Africans are usually attributed to diets containing more animal protein and fat and less fibre.

Lora Hooper is a professor in the Department of Immunology at the University of Texas Southwestern Medical Center (Dallas), and an investigator at the Howard Hughes Medical Institute. Her lab studies immune mechanisms that prevent bacteria from crossing intestinal barriers and entering host tissues.