Dairy intake has been shown to have an inverse relationship with hypertension and several studies show that fermented or sour milk may effectively lower blood pressure in humans.

There is a remarkable amount of support for dietary dairy intake to reduce your chances of becoming hypertensive, although there is little evidence that increasing your milk consumption will lower blood pressure. For instance,

• The National Health and Nutrition Examination Survey (over 10,000 participants) found that low milk consumption was associated a increased incidence of high blood pressure
• In middle-aged Puerto Rican men who drink no milk, hypertension rates were twice as high as in men who drank at least 1 liter per day.
• Lower milk consumption was shown to be a trend in American and Italian hypertensives
• Milk consumption has been tied to a lower rate of thrombotic stroke in men
• Dairy calcium has been associated with lower stroke risk than other forms of calcium in women

Fermented milk has been shown to lower blood pressure in hypertensive rats in at least 5 studies. In human subjects, there are a minimum of 9 studies that show that fermented milk lowers blood pressure. Two of the studies involved tablets containing tripeptides, 4 of the studies focused on milk with fermented tripeptides, and then there is one study focusing on fermented yogurt, one on fermented milk containing y-amniobutyric acid, and one on fermented milk containing whey protein. The duration of the studies varied from 4 to 21 weeks and included 17 to 94 subjects. The longest study (21 weeks) included 39 subjects and used fermented milk containing tripeptides saw an average drop in systolic blood pressure of 6.7 and 3.6 diastolic.

It is hypothesized that the primary mechanism by which fermented dairy products lower blood pressure is by acting as an ACE inhibitor. Several peptides in milk products are known to inhibit ACE, such as Ile-Prp-Pro and Val-Pro-Pro. Certain milk peptides are also known to have opioid-like characteristics.

While drinking fermented milk is not a recommended way to lower blood pressure, the DASH diet, which has proven to be quite effective in lowering blood pressure, does call for low-fat dairy products as part of a healthy diet.

For more information, please see “Milk Peptides and Blood Pressure” found in the 2007 issue of The Journal of Nutrition found at http://jn.nutrition.org/cgi/content/full/137/3/825S.