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Study Finds Higher Fat Variation of DASH Diet Beneficial

The Dietary Approaches to Stop Hypertension (DASH) dietary pattern, which is high in fruits, vegetables, and low-fat dairy foods, significantly lowers blood pressure and LDL cholesterol. In a study published in the February issue of The American Journal of Clinical Nutrition, researchers at the University of California, San Francisco Benioff's Children's Hospital Oakland Research Institute (CHORI) found that a higher fat DASH diet not only lowered blood pressure to the same extent as the DASH diet but also reduced triglycerides and didn't significantly raise LDL cholesterol.

The study tested the effects of substituting full-fat for low-fat dairy foods in the DASH diet on blood pressure and plasma lipids and lipoproteins. The DASH diet was originally developed as a means for lowering blood pressure, and was designed to include low-fat and nonfat dairy foods. When substituted for carbohydrates or unsaturated fats, saturated fats have been consistently shown to increase LDL cholesterol. The DASH diet was developed with research originally sponsored by the National Institutes of Health. Since that time, a number of studies have shown the health benefits of the DASH diet, and it has many of the same characteristics as the Healthy US-Style Eating Pattern, one of three recommended dietary patterns in the 2015 Dietary Guidelines for Americans.

In this study, researchers led by Ronald Krauss, MD; Sally Chiu, PhD; and Nathalie Bergeron, PhD, tested whether the blood pressure benefit, as well as a favorable lipid and lipoprotein profile of the DASH diet, could be maintained with a modification of the DASH diet that included full-fat dairy foods. Compared with the DASH diet, the higher fat DASH diet has more total and saturated fat and less carbohydrate, the latter achieved primarily by reducing fruit juices and other sugars.

The researchers used a randomized crossover trial of healthy individuals who ate a control diet, a standard DASH diet, and a higher fat, lower carbohydrate modification of the DASH diet for three weeks each. The control diet contained less fiber, fruits, and vegetables and more red meat than either of the DASH diets. Each diet period was separated by two-week washout periods, and participants maintained a constant weight during the study periods.

Thirty-six adult participants completed all three diet periods. Blood pressure was reduced similarly in the DASH and higher fat DASH diet compared with the control diet. The higher fat DASH diet significantly reduced triglycerides and large- and medium-sized LDL particles in comparison with the DASH diet, and there was no significant difference in LDL cholesterol response between these diets. The modified higher fat DASH diet presents a possibly effective alternative to the widely recommended DASH diet, with less stringent dietary fat constraints that may promote even broader implementation.

— Source: University of California, San Francisco Benioff Children's Hospital Oakland Research Institute