Adding Protein and Fat to Your Diet May Be The Key to Improving Blood Pressure It's almost as if mainstream nutritionists are just waking up from a bizarre dream in which carbohydrates were good but fats and proteins were bad. What a strange dream! Don't expect to see an end to the "Low Fat = Good Nutrition" mindset anytime soon. But reality does seem to be dawning here and there. HSI Panelist Allan Spreen, M.D., sent me a recent study that appeared in the Journal of the American Medical Association (JAMA), and he included this note: "JAMA published another study backing the lowering of carbs and raising protein and fat for improving both blood pressure and serum lipid profiles. If this keeps up these guys will be saying it's their idea!" In the trial Dr. Spreen refers to, a team of researchers with the OmniHeart Collaborative Research Group compared the effects of three diets. But these weren't weight-loss diets. They were diets solely intended to address high blood pressure. More than 160 subjects with prehypertension or stage 1 hypertension were recruited to undergo six weeks of dieting. Each subject was randomly assigned one of these diets: Carbohydrate Diet: This was modeled on the American Heart Association DASH diet (Dietary Approaches to Stop Hypertension); low in saturated fats, high in carbs from fruits, vegetables and fiber, small amounts of fish, poultry, lean meats, beans and nuts. Protein Diet: This diet contained 10 percent more protein, mostly from beans, nuts, poultry, low-fat milk products and egg substitutes. Like the carb diet, 21 percent of calories came from unsaturated fats Unsaturated Fat Diet: In this diet, 31 percent of calories came from unsaturated fats, primarily monounsaturated fats and oils such as olive oil. Calories from protein totaled 15 percent (as did the carb diet). Right away you can see this is not setting the stage for a revolution, what with an apparent fear of nutritious protein sources (eggs and fish) and an emphasis on low-fat items. Nevertheless, the protein and unsaturated fat diets bested the carb diet in three key measures: systolic blood pressure, triglycerides and LDL cholesterol. Both diets lowered systolic blood pressure more than the carb diet. The protein diet also lowered LDL cholesterol and triglycerides. LDL was not significantly affected by the unsaturated fat diet, but HDL increased and triglycerides went down. In their conclusion the authors note that when a diet is fundamentally healthy, "partial substitution of carbohydrate with either protein or monounsaturated fat can further lower blood pressure, improve lipid levels, and reduce estimated cardiovascular risk." These results should not be a surprise to mainstream nutritionists. Not anymore. After years of mainstream bashing of the Atkins diet (often hysterically portrayed as a lunatic all-bacon-all-the-time diet), the OmniHeart trial is just one more indication that the old guard is coming around. Last year I told you about a one-year study in which 132 obese subjects followed either a low-fat or a low-carb diet. Both groups of dieters experienced about the same overall weight loss. But like the OmniHeart study, heart health factors told the real story. Writing in the Annals of Internal Medicine, the authors stated: "For persons on the low-carbohydrate diet, triglyceride levels decreased more…and high-density lipoprotein cholesterol levels decreased less. "Participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet. Weight loss was similar between groups, but effects on glycemic control were still more favorable with a low-carbohydrate diet." And of course, glycemic control (which can help prevent type 2 diabetes) is one of the most important reasons to follow a low-carb diet. Another study (also reported in the Annals of Internal Medicine last year) evaluated 120 overweight subjects for six months as they followed either a low-fat or a low-carb diet. In that study, triglyceride levels dropped as HDL levels had a greater increase in the low-carb diet compared to the low-fat diet. These two studies didn't examine blood pressure changes, but if I had high blood pressure, I know which diet I'd bet my health on. Sources:
"Effects of Protein, Monounsaturated Fat, and Carbohydrate Intake on Blood Pressure and Serum Lipids" Journal of the American Medical Association, Vol. 294, No. 19, November 16, 2005, jama.ama-assn.org
"Replacing Some Carbohydrates with Protein and Unsaturated Fat May Enhance Heart Health Benefits" NIH News, National Institutes of Health, 11/15/05, nhlbi.nih.gov
"The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One-Year Follow-up of a Randomized Trial" Annals of Internal Medicine, Vol. 140, No. 10, 5/18/04, annals.org
"A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia: A Randomized, Controlled Trial" Annals of Internal Medicine, Vol. 140, No. 10, 5/18/04, annals.org
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