What is the OmniHeart Diet?

I thought it would be helpful to share this study with you, since the Protein Diet they tested fits with our Cancer Prevention Diet as long as you SUBSTITUTE non-dairy products for the dairy, limit sugar to 3g per serving, and confine your animal protein to fish and free-range white meat organic chicken! Also make sure all your carbs comply with our good carb formula.

OmniHeart is short for Optimal Macronutrient Intake Trial to Prevent Heart Disease. The study came up with two diets, one higher in protein and one higher in unsaturated fats than the Dietary Approaches to Stop Hypertension, or DASH diet. The trial compared each diet’s effects on blood pressure and cholesterol.

NOTE:  Consult your doctor before you adopt any diet.

Apple heart

OmniHeart – Optimal Macronutrient Intake Trial to Prevent Heart Disease

Presenter: Lawrence J Appel, MD, MPH (Johns Hopkins University, Baltimore, Maryland)

In the setting of a healthy diet, partial replacement of dietary carbohydrate with protein (about half from plant sources) or with unsaturated fat (mostly monounsaturated) can further lower blood pressure, improve lipid profiles, and reduce estimated coronary heart disease (CHD) risk in people with hypertension or prehypertension, researchers have concluded from the results of the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart).[1] The trial shows, they say, that the widely recommended Dietary Approaches to Stop Hypertension (DASH) diet, a carbohydrate-rich diet, can be improved. The results of OmniHeart were presented at the American Heart Association (AHA) Annual Scientific Session and published in full in JAMA. [2]

Rationale

Although there has been widespread consensus that the optimal diet to reduce cardiovascular risk should be low in saturated fat, the issue of whether the type of macronutrient that replaces the saturated fat should be carbohydrate, protein, or unsaturated fat remains unresolved, with substantial public health implications. The OmniHeart study was set up to evaluate 3 dietary approaches by studying their effects on established coronary risk factors and a selected group of emerging risk factors.[3] The aim was to improve on the DASH diet, which has been shown to lower blood pressure and low-density lipoprotein (LDL)-cholesterol, and is advocated in several major US policy documents, including 2005 dietary guidelines.[4]

Diets

OmniHeart tested 3 healthy diets: a carbohyrate-rich diet similar to the DASH diet, a diet rich in protein (almost half from plant sources), and a diet rich in unsaturated, mostly monounsaturated fat. The carbohydrate diet provided 58% of its calories from carbohydrate, whereas the protein diet and the unsaturated fat diet reduced carbohydrate by 10% and shifted the calories to protein (total 25%) and fat (total 37%), respectively (Table 1). All of the diets were low in saturated fat (6% of calories).

Table 1. Macronutrient Goals

Carbohydrate
Diet
Protein
Diet
Unsaturated Fat
Diet
Carbohydrate (% kcal) 58 48 48
Protein (% kcal) 15 25 15
Fat (% kcal) 27 27 37
Monounsaturated (% kcal) 13 13 21
Polyunsaturated (% kcal) 8 8 10
Saturated (% kcal) 6 6 6

The protein diet contained more legumes, nuts, seeds, and other vegetable protein, poultry, and egg product substitutes than the other 2 diets (Table 2).

Table 2. Sources of Protein (Average Daily Intake)

Unit Carbohydrate
Diet
Protein
Diet
Unsaturated Fat
Diet
Legumes, nuts, seeds, vegetable protein oz 1.3 3 1.2
Dairy, dairy products cup 2.1 2.5 1.9
Beef, pork, ham oz 0.9 1.1 1.0
Poultry oz 1.6 2.6 1.8
Fish oz 1.1 1.3 1.0
Egg produce substitutes oz 0.2 1.1 0.1

All 3 diets provided 2100 kcal/day and comprised cholesterol 140 mg/day, fiber 30 g/day, sodium 2300 mg/day, potassium 4700 mg/day, magnesium 500 mg/day, and calcium 1200 mg/day.

Subjects spent 3 periods of 6 weeks on each diet, interspersed with 2- to 4-week washout periods, during which subjects ate their own food. At the start of the study there was a run-in period of 6 days, after which subjects were randomized to 1 of the 6 sequences of the 3 diets.

Researchers provided all of the food during the study. Participants came to the study site weekdays for lunch. Food for the other 2 daily meals plus snacks and weekend meals were provided to take home.

Calories were adjusted to maintain weight to avoid confounding effects of weight loss in the study. Sodium and potassium intake were also maintained.

Participants

People were recruited into OmniHeart at 2 clinical centers: Johns Hopkins Medical Institutions (Baltimore, Maryland) and Brigham and Women’s Hospital (Boston, Massachusetts). Entry criteria for OmniHeart were age ≥ 30 years and systolic blood pressure (SBP) 120-159 mm Hg or diastolic blood pressure (DBP) 80-99 mm Hg. This range of blood pressure is higher than normal and includes persons with prehypertension and hypertension. Potential participants were excluded if they had diabetes, prior or active cardiovascular disease, LDL-cholesterol > 220 mg/dL, triglycerides > 750 mg/dL, or if they were on medication for reduction of blood pressure or lipid levels. A total of 164 subjects were recruited, mean age 53.6 years, 45% women, 55% African American. The study population’s mean weight was 87.3 kg/m2, body mass index 30.2 kg/m2, and blood pressure 131/77 mm Hg. Twenty percent of subjects were hypertensive.

Effects on Blood Pressure and Lipids

Compared with baseline levels, which were obtained when participants were eating their own food, all 3 diets lowered SBP and DBP (Table 3).

Table 3. Blood Pressure: Changes From Baseline

Baseline
(mm Hg)
Mean Change From Baseline (mm Hg)
Carbohydrate Protein Unsaturated Fat
SBP (all) 131.2 -8.2 -9.5 -9.3
SBP (hypertension only) 146.5 -12.9 -16.1 -15.8
SBP (prehypertension only) 127.5 -7.0 -8.0 -7.7
DBP 77.0 -4.1 -5.2 -4.8

DBP = diastolic blood pressure; SBP = systolic blood pressure

Levels of LDL-cholesterol and triglycerides were also lowered on all 3 diets. High-density lipoprotein (HDL)-cholesterol was also reduced on the carbohydrate and protein diets, but remained unchanged on the unsaturated fat diet. Triglycerides were unchanged on the carbohydrate diet, but were reduced on the protein and unsaturated fat diets (Table 4).

Table 4. Blood Pressure: Changes From Baseline

Baseline
(mm Hg)
Mean Change From Baseline (mm Hg)
Carbohydrate Protein Unsaturated Fat
LDL-cholesterol (all) 129.2 -11.6 -14.2 -13.1
LDL-cholesterol ≥ 130 mg/dL 156.7 -19.8 -23.5 -21.9
LDL-cholesterol < 130 mg/dL 105.2 -4.4 -6.1 -5.4
HDL-cholesterol 50.0 -1.4 -2.6 -0.3
Triglycerides 101.5 0.1 -16.4 -9.3

HDL = high-density lipoprotein; LDL = low-density lipoprotein

Comparison Between Diets

Compared with the carbohydrate diet, both the protein diet and the unsaturated fat diet further reduced SBP and DBP (Table 5). All prehypertensive subjects and hypertensive subjects showed reductions in SBP on the protein and unsaturated fat diets, although the reduction was not statistically significant in the prehypertensive subjects on the unsaturated fat diet.

Table 5. Blood Pressure: Differences Between Diets

Mean Change From Carbohydrate Diet
Protein Unsaturated Fat
SBP -1.4 -1.3
P value <.01 <.01
SBP (hypertension only) -3.5 -2.9
P value .01 .02
SBP (prehypertension only) -0.9 -0.9
P value .047 .06
DBP -1.2 -0.8
P value <.01 .02

DBP = diastolic blood pressure; SBP = systolic blood pressure

LDL-cholesterol was significantly decreased on the protein diet, but the unsaturated fat diet had no significant effect compared with the carbohydrate diet (Table 6). HDL-cholesterol was lowered on the protein diet, but raised on the unsaturated diet. Compared with the carbohydrate diet, the protein and unsaturated fat diets each significantly reduced triglycerides.

Table 6. Lipids: Differences Between Diets

Mean Change From Carbohydrate Diet
Protein Unsaturated Fat
LDL-cholesterol -3.3 -1.5
P value .01 .22
HDL-cholesterol -1.3 1.1
P value .02 .03
Triglycerides -15.7 -9.6
P value <.01 .02

HDL = high-density lipoprotein; LDL = low-density lipoprotein

Coronary Heart Disease Risk

The 10-year risk of CHD risk based on the Framingham risk equation was lowered on all 3 diets, although the risk was lowest (and similar) for subjects following the protein and the unsaturated fat diets (Table 7). Compared with the carbohydrate diet, the risk was further lowered on the protein and unsaturated fat diets.

Table 7. Estimated 10-Year CHD Risk From Framingham Equation

Baseline Carbohydrate Protein Unsaturated Fat
Estimated 10-year CHD risk 5.1 4.3 4.0 4.1
Change from baseline (%) ref -16.1 -21.0 -19.6
Change from carbohydrate (%) ref -5.8 -4.2

CHD = coronary heart disease

Read the rest of the study here.

Implications

This study provides “convincing evidence that the amount of carbohydrates, protein and fat people eat influences cardiovascular risk and risk of CHD,” Dr. Appel concluded. “This work will help policy makers in making dietary recommendations and guidelines to help prevent heart disease,” he continued. “Both the general public and the scientific research community are extremely interested in the health effects of shifting calories from carbohydrates.” The results from the OmniHeart study will guide future nutrition recommendations and may help reduce heart disease and stroke and improve the public health of all Americans, Dr. Appel believes.

AHA-designated discussant Ira Goldberg, MD (Columbia University College of Physicians and Surgeons, New York, NY), said that one of the real “pluses” of OmniHeart was that it was a mixed ethnic study, so many of the results can be extended to large populations. A “troubling aspect,” however, was that 45% of the study population was obese and 34% overweight, so the primary objective of any other study in the future should be weight reduction, he recommended.

This aspect of the study is also brought up by Myron H. Weinberger, MD (Indiana University Medical Center, Indianapolis), in an editorial accompanying publication of the OmniHeart results in JAMA. [5] Dr. Weinberger also believes that it is “reasonable” to expect that “the next rendition of the DASH and successor diets by the [OmniHeart] investigators will focus on weight loss,” as this is “perhaps the most important intervention.”

~ Be Well!

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