DASH Diet Changes Better Reduce High Blood Pressure, Improve Lipids and
Promote Cardiovascular Health
Substituting carbohydrates with protein and mono-saturated fats can further lower blood pressure, improve lipid levels and reduce cardiovascular risk
Boston, MA and Dallas, TX – In the mid-1990s, researchers at Brigham and Women’s Hospital (BWH), John Hopkins University and colleagues presented what is now considered a “gold standard” of dietary recommendations for reducing high blood pressure and “bad” LDL cholesterol. The Dietary Approaches to Stop Hypertension (DASH) diet found that a carbohydrate-rich diet emphasizing fruits, vegetables and low-fat dairy products and that is reduced in saturated fat, total fat and cholesterol, substantially reduces blood pressure and “bad” LDL cholesterol. However, the diet also lowered “good” HDL cholesterol and had no effect on triglycerides, both of which are associated with an increased cardiovascular disease risk.
To develop new standards for an even healthier diet, two of the original DASH group, including BWH’s Frank M. Sacks, MD, initiated the OmniHeart Randomized Trial (the Optimal Macronutrient Intake Trial to Prevent Heart Disease) which found that among three diets designed to further lower risk, the risk was lowest for people following a diet emphasizing protein and unsaturated fat as opposed to the original DASH diet which emphasized carbohydrates. These data will be published in the November 16, 2005 issue of the Journal of the American Medical Association and simultaneously presented at a late-breaking clinical trials session at the American Heart Association (AHA) Scientific Sessions 2005.
According to Sacks, “Reducing cardiovascular risk is imperative to leading a healthy lifestyle and, while the DASH-low sodium diet remains a hallmark to prevent and treat hypertension, there are additional growing cardiovascular health risks that we need to address. The new recommendations, which include substituting some carbohydrates with protein and fats, can help dramatically reduce the risk factors associated with cardiovascular disease and heart attack.”
In this study, researchers enrolled 164 adults, 30-years-old and older, and gave them three healthy diets: one diet was rich in carbohydrates (55 percent of calories) and is very close to the DASH diet; the second diet shifted 10 percent of its calories to protein, about two-thirds from plant sources and one-third from chicken and egg whites; and, the third diet shifted 10 percent of its calories to unsaturated fat, predominantly monounsaturated fat as in olive or canola oils. The study participants all had higher-than-normal blood pressure and about half the subjects were African American, a population that has a greater-than-average risk of developing hypertension.
The researchers found that compared to the participants’ usual diet, each of the three diets lowered blood pressure, LDL cholesterol and estimated coronary heart disease risk. However, the unsaturated fat diet and protein diets both produced improvements over the DASH-like carbohydrate-rich diet. Specifically:
- The protein diet decreased blood pressure by 1.4 mm Hg overall, and by 3.5 mm Hg among those with hypertension; decreased LDL cholesterol by 3.3 mg/dL; and, decreased triglycerides by 15.7 mg/dL.
- The unsaturated fat diet decreased systolic blood pressure by 1.3 mm Hg overall and by 2.9 mm Hg among those with hypertension; increased HDL cholesterol by 1.1 mg/dL; and, lowered triglycerides by 9.6 mg/dL.
- Compared to baseline, each diet reduced heart disease risk by 14 to 31 percent. However, the protein and unsaturated fat diets reduced risk substantially more than the carbohydrate diet, 11 to 13 percent in the women, and 12 to 13 percent in the men.
Based on these results researchers recommend that individuals concerned about high blood pressure and cardiovascular risk should extend the benefits of the original DASH diet by substituting protein or monounsaturated fats for 10 percent of dietary carbohydrates.
Daily Diet Example
To help individuals better understand the rich and varied options offered through the modified DASH diet, Janis Swain, RD, MS, who worked with Sacks on developing appropriate food choices for participants, outlined the following heart-healthy recipes and meal examples.
In the dinner examples below, all three leveraged a simple penne bean pasta that was modified to either increase protein or monounsaturated fat. The recipe included pasta, navy beans, spaghetti sauce, spinach, olive oil, onion and garlic, chili pepper and sage.
2100 Calorie Sample Dinner menu
Carbohydrate Diet
- 1 ½ c. Penne Bean Pasta Recipe with 2 tsp. Olive Oil
- 1 oz. Beef Meatballs
- 1 Tbsp Parmesan Cheese
- ¾ c. Romaine lettuce
- ½ c. Cherry Tomatoes with 2 tsp. Italian Dressing (fat free)
- 1 tsp. Safflower Oil
- 1 c. Fresh Grapes
- 1 small Peppermint Patty
Protein Diet
- 2 c. Penne Bean Pasta Recipe with 2 ½ tsp. Olive Oil
- 1 oz. Beef Meatballs
- 1 Tbsp. Parmesan Cheese
- ¾ c. Romaine lettuce
- ¾ c. Cherry Tomatoes with 1 Tbsp. Italian Dressing (fat free)
- 1 oz. dried raisins and cherries
Unsaturated Fat Diet
- 1 ¼ c. Penne Bean Pasta Recipe with 1 Tbsp. Olive Oil
- 1 ¼ oz. Beef Meatballs
- 1 c. Romaine lettuce &
- ½ c. Cherry Tomatoes with 1 Tbsp. Olive Oil and
- 1 Tbsp. Vinegar
- ¾ c. vegetable juice
- 1 oz. dried raisins and cherries
Although breakfast was similar for all three diets and included fresh fruit and fruit juice, whole grain cereal and skim milk, the lunches were differentiated. The protein diet included more chicken in the chicken salad sandwich along with hummus, while the monounsaturated fat diet incorporated less chicken and added olive oil to the sandwich mix. For the complete day’s menus, nuts and seeds, other fruits and vegetables and low-fat dairy complemented all the meal plans.
“What this study demonstrates is that minor changes in the diet can dramatically reduce risk of coronary heart disease and associated risks,” stated Sacks, who is also a professor of Medicine at Harvard Medical School. “Simple changes in diet – substituting protein including beans, nuts and seeds or monosaturated fats including peanuts, olives and olive oils – for 10 percent of carbohydrates could potentially add years to an at-risk individual’s life.”
The study was conducted at Johns Hopkins Medical Institutions and Brigham and Women’s Hospital. Frank Sacks, MD led the Brigham and Woman’s Hospital clinical center and Lawrence Appel, MD led the John Hopkins clinical center. The National Heart, Lung, and Blood Institute funded the study.
Please contact BWH Media Relations for more information at (617) 534-1600 or BWHMediaRelations@partners.org.
BWH is a 747-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare System, an integrated health care delivery network. BWH is committed to excellence in patient care with expertise in virtually every specialty of medicine and surgery. The BWH medical preeminence dates back to 1832 and today that rich history in clinical care is coupled with its national leadership in quality improvement and patient safety initiatives, dedication to educating and training health care professionals, and strength in biomedical research. With $370M in funding and more than 500 research scientists, BWH is an acclaimed leader in clinical, basic and epidemiological investigation - including the landmark Nurses Health Study, Physicians Health Studies, and the Women's Health Initiative. For more information visit www.brighamandwomens.org.
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