The Western diet high in saturated fat alters immune function even before it packs on the pounds, according to a study from the University of South Wales. The researchers examined the impact of a saturated fat-laden diet on a class of immune cells, called T lymphocytes or T cells. They fed mice the Western diet for nine weeks to observe how this diet might affect T cell response. They had expected a drop in T cell activity, but instead say an increase in T cell numbers, a sign of impending autoimmune disease. In addition, they were surprised to see T cell responses were altered even in the absence of obesity and obesity-induced inflammation. It appears that diets high in saturated fat alter the structure of the T cell membranes which, in turn, alters immunity. This occurs prior to the onset of weight gain.
Pollock A, Tedia N, Hancock S, et al: Prolonged intake of dietary lipids alters membrane structure and T cell responses in LDLr-/-mice. Journal of Immunology 2016; 196:3993-4002.