To describe the nutrient and food composition of the diets tested in the Optimal Macronutrient
Intake Trial to Prevent Heart Disease (OmniHeart).
Two center, randomized, three-period crossover, controlled feeding trial that tested
the effects of three healthful diet patterns on blood pressure, serum lipid levels,
and estimated cardiovascular risk.
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.
The OmniHeart trial studied three diet patterns that differed in macronutrient composition:
a carbohydrate-rich diet similar to the Dietary Approaches to Stop Hypertension 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. Sodium was 2,300 mg at the 2,100 kcal energy level
and was indexed across energy levels. Calcium, magnesium, and potassium were consistent
with recommendations for the Dietary Approaches to Stop Hypertension diet and also
indexed to energy levels. Each diet pattern met the major nutrient recommendations
set by the Dietary Guidelines for Americans 2005. The 10% protein increase in the higher protein diet emphasized plant protein; however,
meat and dairy food sources were also increased somewhat. 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. All three
diets reduced blood pressure, total and low-density lipoprotein cholesterol levels,
and estimated coronary heart disease risk.
The OmniHeart diet patterns offer substantial flexibility in macronutrient intake
that should make it easier to eat a heart-healthy diet and reduce cardiovascular disease