Journal Name:
J. Am. Diet Assoc.
Article Title:
Characteristics of the diet patterns tested in the optimal macronutrient intake trial to prevent heart disease (OmniHeart): options for a heart-healthy diet.
Date Written:
2008
Volume:
108
Number:
2
Page:
257
Author(s):
Swain, J.F.; McCarron, P.B.; Hamilton, E.F.; Sacks, F.M.; Appel, L.J.
Article:
It is well accepted that the modification of diet can have beneficial effects on blood pressure, blood lipid levels, and overall cardiovascular disease (CVD) risk. The Dietary Approaches to Stop Hypertension (DASH) trial was an 11-week controlled feeding trial that studied three diet patterns. Results showed that a diet pattern, now referred to as the DASH diet, rich in fruits, vegetables, and low-fat dairy products; reduced in saturated fat and total fat; and modestly increased in protein substantially lowered blood pressure compared to a typical American diet. It also lowered plasma total and low-density lipoprotein (LDL) cholesterol levels without raising blood triglyceride concentrations, and lowered high-density lipoprotein cholesterol levels resulting in no change in the LDL:high-density lipoprotein cholesterol ratio.
The Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart) tested the effects of partially substituting carbohydrate with protein and unsaturated fat on blood pressure, blood lipid levels, and estimated CVD risk. This trial tested the effects of three diets that were variations of the DASH diet pattern: a carbohydrate-rich diet (58% carbohydrate, 15% protein, and 27% fat), a higher protein diet that had 10% more protein and 10% less carbohydrate (48% carbohydrate, 25% protein, and 27% fat), and a higher unsaturated fat diet that had 10% more unsaturated fat and 10% less carbohydrate (48% carbohydrate, 15% protein, and 37%fat). Each diet contained 6% saturated fat and 100 to 200 mg cholesterol.
The objective of this article is to describe within the context of the research study, the nutrient and food composition of the diets tested in the OmniHeart trial. The OmniHear trial consisted of one hundred sixty-four participants with prehypertension and hypertension. During the 19 weeks of feeding, participants were required to consume only food prepared as part of the trial.
Olive oil, canola oil, and olive oil spread were used liberally to achieve the unsaturated fat content of the higher unsaturated fat diet. The 10% reduction in carbohydrate in the higher protein diet and the higher unsaturated fat diet was achieved by replacing some fruits with vegetables, reducing sweets, and using smaller portions of grain products. In comparison to baseline, blood pressure, LDL cholesterol levels, and estimated coronary heart disease risk were 16% to 21% lower on each of the OmniHeart diets. Moderate replacement of carbohydrate with either protein or unsaturated fat further reduced CVD risk. Blood triglyceride levels were reduced only in the higher protein and higher unsaturated fat diets.
The OmniHeart carbohydrate-rich diet is similar to the well-recognized DASH diet, the higher protein diet provides a healthful alternative for those who wish to consume additional protein, and the higher unsaturated fat diet is similar to a Mediterranean-style diet. Partial substitution of carbohydrate with protein and unsaturated fat led to further improvement in CVD risk factors. Given the variety of eating patterns in the North American population, the OmniHeart diet patterns offer substantial flexibility in macronutrient intake that should make it easier to eat a heart healthy diet and reduce CVD risk. Canola oil is an important of this diet and can be easily incorporated into many food and eating plans.
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