New insight into how the Mediterranean diet may lower blood pressure

Researchers found in mice that the unsaturated fats in the Mediterranean diet combine with nitrites and nitrates in some consumed vegetables to form nitro fatty acids, which attach to and inhibit an enzyme possibly involved in hypertension.

by John Tyburski

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First published at DailyDigest News on May 19, 2014

For years now, scientists have consistently observed a link between the Mediterranean diet and healthy hearts. While clear reductions in risks for a variety of cardiovascular events have been demonstrated, researchers have not been able to pinpoint why the diet exerts these beneficial effects on the cardiovascular system. This week, researchers at Kings College London and their collaborators at other institutions in the U.S. report on exciting new insights into a mechanism linking the Mediterranean diet with lower blood pressure in mice.

Once consumed, the diet’s unsaturated fats and vegetable nitrates and nitrites form nitro fatty acids—fatty acids with nitrogen dioxide added onto them. These reactive fatty acids form adducts with soluble epoxide hydrolase (she), an enzyme possibly linked to hypertension. When nitro fatty acids adduct to the enzyme, they inhibit its activity. The researchers found that inhibiting sEH led to an accumulation of the endogenous substrates of this enzyme, resulting in lower blood pressure in mice.

The researchers generated what is called a “knockin” (KI) mouse in which an altered form of sEH, a form that still works but is not inhibited by nitro fatty acids, is “knocked in” to the mouse’s genome. Nitro fatty acids inhibited the activity of sEH and lowered blood pressure in normal “wild type” mice and in the mice of a hypertension model but not in the KI mice. The experimental design provides very strong evidence that inhibition of sEH may be a key target in managing hypertension.

The Mediterranean diet is so-named for the dietary tendencies of European, Middle Eastern, and North African nations surrounding the Mediterranean. The diet is characterized by an emphasis on fruits, vegetables, whole grains, nuts, and legumes. Olive oil and other unsaturated fats serve in place of butter, and fish and poultry are eaten at least twice a week with red meat limited to only a few times a month. Herbs and spices prevail over salt in flavoring foods, and red wine in moderation often accompanies the meals.