Abstract
BACKGROUND: Despite diet being a first-line strategy for preventing cardiovascular disease, the optimal macronutrient profile remains unclear. We studied the effects of macronutrient profile on subclinical cardiovascular injury and inflammation. METHODS: OmniHeart was a randomized 3-period, crossover feeding study in 164 adults with high blood pressure or hypertension (SBP 120-159 or DBP 80-99 mm Hg). Participants were fed each of 3 diets (emphasizing carbohydrate (CARB), protein (PROT), or unsaturated fat (UNSAT)) for 6-weeks, with feeding periods separated by a washout period. Weight was held constant. Fasting serum was collected at baseline while participants ate their own diets and after each feeding period. High-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity C-reactive protein (hs-CRP) were measured in stored specimens. RESULTS: The average age was 53.6 years, 55% were African American, and 45% were women. At baseline, the median (25th-percentile, 75th-percentile) hs-cTnI was 3.3 ng/L (1.9, 5.6) and hs-CRP was 2.2 mg/L (1.1, 5.2). Compared to baseline, all 3 diets reduced hs-cTnI: CARB -8.6% (95%CI: -16.1, -0.4), PROT -10.8% (-18.4, -2.5), and UNSAT -9.4% (-17.4, -0.5). Hs-CRP was similarly changed by -13.9 to -17.0%. Hs-cTnI and hs-CRP reductions were of similar magnitudes as SBP and low-density lipoprotein cholesterol (LDLc) but were not associated with these risk-factor reductions (P-values = 0.09). There were no between-diet differences in hs-cTnI and hs-CRP reductions. CONCLUSIONS: Healthy diet, regardless of macronutrient emphasis, directly mitigated subclinical cardiac injury and inflammation in a population at risk for cardiovascular disease. These findings support dietary recommendations emphasizing healthy foods rather than any one macronutrient. TRIAL REGISTRATION: This trial is registered at clinicaltrials.gov, number: NCT00051350; URL: https://clinicaltrials.gov/ct2/show/NCT00051350.