A new study suggests that increased intake of low-fat dairy foods, as part of a Dietary Approaches to Stop Hypertension (DASH)-based eating plan, may lower blood pressure more effectively than a conventional low-fat diet.
Published in the American Journal of Clinical Nutrition, researchers compared two diets -- one based on the DASH eating pattern and the other a typical low-fat diet -- combined with increased physical activity. The study found that for comparable weight loss, the DASH-based diet resulted in a greater decrease in blood pressure than did the low-fat diet.
The DASH eating plan was developed by the U.S. National Heart, Lung and Blood Institute (NHLBI) and is comprised of three daily servings of low-fat dairy foods and 8-10 daily servings of fruits and vegetables. The government recently highlighted the health benefits of DASH by recommending the eating plan in the new Dietary Guidelines and MyPyramid, and NHLBI designated May as National Blood Pressure Education Month.
The study participants, consisting of 54 middle-aged men with a body mass index of about 30, were assigned to one of the two diets for 12 weeks and engaged in similar levels of physical activity. Both diet plans included low-fat or nonfat dairy foods, fruits and vegetables, but at week 12, the DASH-based group reported a higher intake of dairy foods (approximately four daily servings compared to 2.5 among the low-fat group). There was no reported difference in fruit and vegetable intake between the two diet groups.
The authors speculate that a combination of factors such as lower sodium and increased potassium, calcium and magnesium -- key nutrients found in dairy -- may be responsible for the greater effect of the DASH-based diet on the obesity-related elevated blood pressure. Potassium has long been seen as a key nutrient in lowering blood pressure. Each eight-oz. serving of milk provides about 350mg to 400 mg of potassium, or 11% of the daily value per serving.
According to the Dairy Council of California, fluid milk is the number-one source of potassium in the American diet, and dairy foods provide 18% of the potassium in the U.S. food supply.
All is not good news for milk, however. A study published this week suggests that the more milk kids drink, the fatter they grow -- and skim milk is the worst.
"Contrary to our hypotheses, dietary calcium and skim milk were associated with weight gain," Brigham and Women's Hospital and Harvard researchers said. "But dairy fat was not."
It could be the youngsters drink lower-fat milk more freely. Thus, it may not be milk itself but the calories in milk that are to blame.
"Children should not drink milk as a means of controlling weight," researchers said.