With one in three Americans having hypertension and nearly 30 percent of adults having prehypertension, you most likely counsel clients frequently about dietary and lifestyle changes to help reduce blood pressure. When discussing dietary advice with people, we know it’s important to keep in mind that “People eat food, not nutrients,” so often a whole foods approach works best. But as professionals, we want to know how foods work to maintain health. We want to know the mechanisms behind the beneficial effects nutrient-rich foods have on health outcomes – in intricate detail. Blood pressure is no exception. New research into the how of blood pressure control published this spring in the American Journal of Hypertension reveals a potentially unique role for proteins naturally found in milk.
So to humor your nerdy need for details, here are some of the main points from the American Journal of Hypertension study:
- Since obesity and reduced muscle strength are both associated with increased blood pressure, researchers at Florida State University examined the impact of milk proteins combined with moderate-intensity exercise training three days a week on blood pressure, arterial function and muscle strength in 33 obese sedentary young women with hypertension or prehypertension.
- The women were randomly assigned to receive 30g of whey or casein supplementation or a carbohydrate control of equal calories for four weeks.
- Results showed that supplementation with casein and whey protein, combined with exercise training, reduced systolic blood pressure and arterial stiffness, while no changes occurred in the control group.
- Exercise without dairy protein did not affect arterial function, indicating a potentially unique role for dairy proteins in lowering systolic blood pressure. One potential mechanism, the authors suggest, is the ability of bioactive milk peptides to inhibit the enzyme responsible for vascular constriction (angiotensin-converting enzyme).
These results are consistent with previous studies —Nakamura 2009 and Nakamura 2011 — showing dairy proteins may have a favorable effect on blood pressure and vascular function in hypertensive subjects.
The 2010 Dietary Guidelines for Americans noted moderate evidence that consumption of milk and milk products is associated with improved bone health especially in children and adolescents and reduced risk of cardiovascular disease, type 2 diabetes and lower blood pressure in adults. This new study expands our knowledge about the potential blood pressure lowering effect of dairy foods, by identifying milk protein as one important component.
A clinical trial among middle-aged and older adults with high blood pressure demonstrated that just one change– adding four servings of non-fat milk, yogurt, or cheese to their routine diets, totaling 1800 calories – brought about a significant reduction of systolic blood pressure as well as pulse pressure, an indicator of vascular health. That’s the whole foods side of the equation at work.
When taking a whole foods approach to blood pressure control, the DASH eating plan– a dietary pattern rich in fruits, vegetables, and low-fat dairy foods — may be effective for some people. It was designed to provide abundant amounts of minerals shown to help reduce blood pressure, such as calcium, potassium, and magnesium. In addition to these minerals that are found in milk, we think that milk proteins may also play a role. Judy Doherty’s blog post on how to help your clients follow the DASH diet, provides helpful resources and tips for doing that. And don’t forget to check out our recipes to help your clients easily incorporate dairy foods into their daily diet.