Milk, soya proteins lower BP modestly

Supplements of milk and soy protein lower blood pressure modestly among hypertensive patients.

Hypertension or high blood pressure is a “silent killer” that can cause  heart attacks, stroke, heart failure and kidney damage. Previous studies have shown that a diet rich in low-fat dairy products reduces blood pressure.

Researchers evaluated the effects of milk and soy protein supplements and a carbohydrate supplement among 352 adults who either had pre-hypertension or stage 1 hypertension - that is, systolic readings (the top number) ranging from 120 to 159 mmHg and diastolic blood pressure readings (the bottom number) from 80 to 95 mmHg. Ideally, pressures should be below 120 over 80. Each person took 40 grams of soy protein, milk protein, or complex carbohydrate supplementation for 8 weeks in a random order. The supplements used were formulated in a way that allowed researchers to compare the effects of soy protein, milk protein, and refined complex carbohydrate on blood pressure without changing sodium, potassium, and calcium. The carbohydrate supplement served as a comparison. The participants' blood pressure was evaluated thrice at 2 baseline and 2 termination visits during each intervention phase. Each eight-week phase was followed by a three-week washout period when study participants did not take supplements.

It was found that over an eight-week intervention, soy protein was associated with a 2 mm reduction in systolic blood pressure. While milk protein supplement was associated with a 2.3 mm reduction in blood pressure readings compared to the refined carbohydrate supplement.

While the reduction in blood pressure was small, the benefits could translate to reduced numbers of strokes and other cardiovascular problems in the population as a whole, according to the researchers. The researchers suggest that replacing some refined carbohydrates - such as white bread and white rice - with soy or milk protein might be an important component of nutrition intervention strategies for the prevention and treatment of hypertension. Small changes could make a difference. Researchers suggest replacing animal fat with soy protein - such as substituting a veggie burger with soy protein for a hamburger with animal protein, at least occasionally. People who want to maintain a healthy blood pressure must control their diet, not smoke and adopt the DASH diet (Dietary Approaches to Stop Hypertension) which is a reasonable eating plan and monitor blood pressure regularly.

Among the study's flaws was that the researchers did not measure blood pressure for 24 hours, using an ambulatory monitor, the number of participants few and the duration of study small. Future studies are needed as this is a very preliminary finding though it does reflect the importance of diet and modifying risk factors.

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