Low-fat Dairy Products Lower Blood Pressure

In a recently reported NIH-funded population study, systolic blood pressure (the first and higher number in a blood pressure reading) was lowest among the participants who consumed the most dairy products.

The association of lower systolic pressure with higher dairy intake was seen mainly in those consuming the least number of calories from saturated fat.

Can a diet high in calcium lower blood pressure? Some researchers have claimed that it can. But, despite the high calcium content of dairy products, in this NIH study blood pressure was unrelated to calcium intake. Diastolic blood pressure, the second and lower number, was not associated with dairy consumption in this study.

Some of the findings in this population study are consistent with the results from short-term, controlled clinical trials with the DASH diet. DASH (Dietary Approaches to Stop Hypertension) is an eating plan emphasizing fruits, vegetables, and low-fat dairy products.

The diet includes whole grains, poultry, fish, and nuts; it contains only small amounts of red meat, sweets, and sugar-containing beverages; and it has small amounts of saturated fat and cholesterol. Guidelines adopted in 2003 by a national committee of high blood pressure treatment experts encourage Americans to follow the DASH diet.

Over an eight-week period, the DASH diet lowered systolic pressure by 11.4 mm Hg and diastolic pressure by 5.5 mm Hg, on average, among people with hypertension. Among study participants who were not hypertensive, systolic pressure fell by 3.5 mm Hg and diastolic pressure dropped 2.1 mm Hg.

In another study, subjects followed either a typical American diet or the DASH diet, but the amount of dietary salt was varied from person to person. At every level of salt intake, blood pressures were lower on the DASH diet, and blood pressure was lower among people following the lowest-salt version of either diet ("typical" or DASH).

It's not clear why people on a low-fat, high-dairy diet have lower systolic blood pressures or how much each component of the DASH diet contributes to its beneficial effects.
Nonetheless, these studies show that dietary measures can have a major impact on blood pressure and that low-fat dairy products are probably an important feature of a blood pressure-lowering diet.