Johns Hopkins professor, Lawrence Appel, M.D., suggests improvements to the DASH diet to help lower blood pressure and improve lipids.
If you have hypertension, your doctor most likely recommended that you make changes in your diet. That’s because a variety of dietary factors -- from salt and alcohol to fruits and vegetables -- can influence blood pressure, and getting the right amounts of these foods can go a long way toward keeping your blood pressure under control.
In fact, for the past 10 years, research has been accumulating that a carbohydrate-rich diet that emphasizes fruits, vegetables, and low-fat dairy products and limits saturated fat and cholesterol -- the so-called DASH diet -- can substantially lower blood pressure. The DASH diet also lowers low-density lipoprotein (LDL) cholesterol.
But can the DASH diet be improved? While following the DASH diet can help lower both your blood pressure and LDL cholesterol, it won’t do much for the other lipids (fats) in your blood. For example, the DASH diet reduces levels of high-density lipoprotein (HDL) cholesterol (the “good” cholesterol that protects against heart attacks and strokes). In addition, the DASH diet has no effect on triglycerides (another blood lipid that increases the risk of heart attacks and strokes).
So Lawrence Appel, M.D., (coauthor of the Johns Hopkins Hypertension and Stroke White Paper) and his colleagues decided to investigate whether these drawbacks to the DASH diet might be minimized with a little tweaking of the DASH diet’s components -- specifically, the mix of carbohydrate, fat, and protein. Here are what they did and what they found.
The researchers compared three different healthy diets in 164 adults with prehypertension or mild hypertension. The first diet resembled the traditional DASH diet -- rich in carbohydrates. In the second diet, some of the carbohydrates were replaced with protein, about half of which came from plant sources such as beans. For the third diet, unsaturated fat, primarily healthy monounsaturated fat, substituted for a portion of the carbohydrates.
All three diets were low in saturated fat, cholesterol, and sodium and rich in fruits, vegetables, fiber, potassium, and other minerals. The participants were then randomly assigned to one of the three diets for six weeks. After a two- to four-week break, participants began a six-week trial of another diet and continued until they had eaten all three diets. The participants’ blood pressure, cholesterol, and triglyceride levels were measured during each phase of the study.
What Was Found -- All three diets lowered blood pressure, but the protein-rich diet and the one that emphasized monounsaturated fat lowered blood pressure even more than did the carbohydrate-rich, DASH diet. What’s more, both the protein- and monounsaturated- fat diets lowered triglycerides -- which the traditional DASH diet did not. In addition, the monounsaturated-fat diet raised HDL levels.
