Myocardial infarction (MI) is one of the leading causes of death in the world. Epidemiological studies have shown that dietary flavonoids are inversely related to cardiovascular morbidity and mortality. The study aimed to determine whether quercetin supplementation can improve inflammatory factors, total antioxidant capacity (TAC) and quality of life (QOL) in patients following MI. This randomized double‐blind, placebo‐controlled trial was conducted on 88 post‐MI patients. Participants were randomly assigned into quercetin (n = 44) and placebo groups (n = 44) receiving 500 mg/day quercetin or placebo tablets for 8 weeks. Quercetin supplementation significantly increased serum TAC compared to placebo (Difference: 0.24 (0.01) mmol/L and 0.00 (0.00) mmol/L respectively; p < .001). TNF‐α levels significantly decreased in the quercetin group (p = .009); this was not, however, significant compared to the placebo group. As for QOL dimensions, quercetin significantly lowered the scores of insecurity (Difference: −0.66 (12.5) and 0.00 (5.55) respectively; p < .001). No significant changes in IL‐6, hs‐CRP, blood pressure and other QOL dimensions were observed between the two groups. Quercetin supplementation (500 mg/day) in post‐MI patients for 8 weeks significantly elevated TAC and improved the insecurity dimension of QOL, but failed to show any significant effect on inflammatory factors, blood pressure and other QOL dimensions.

BackgroundThe aim in this study was to investigate the effect of vitamin D (25(OH)D3) supplementation on heat shock protein 60 (HSP 60) and other inflammatory markers (IL-17, TNF-α, PAB) in patients with coronary heart disease (CHD).MethodsIn this double-blind, randomized clinical trial, we recruited 80 male and female patients aged 30–60 with CHD and 25(OH)D3 serum levels < 30 ng/ml from Rasool-e-Akram Hospital in Tehran, Iran. Serum levels of HSP 60 as primary outcome, and 25(OH)D3, IL-17, TNF-α, PAB, lipid profiles and parathyroid hormone (PTH) as secondary outcomes were measured at baseline and post-intervention. We randomly assigned eligible participants to a placebo group (N = 40) or an intervention group (N = 40) (50,000 IU/wk. vitamin D supplement) for eight weeks.ResultsThe results demonstrated that vitamin D supplementation resulted in a significant increase in 25(OH) D3 serum levels in the intervention group compared to the placebo group (46.86 vs. 7.28 ng/ml). PTH levels decreased in the intervention group compared to the placebo group (− 19.81 vs. 2.92 pg/ml) after eight weeks of supplementation. Furthermore, we observed a significant change in waist circumference (− 0.97 vs. -0.26 cm), fat percentage (−.13 vs. 0.1%), systolic blood pressure (− 3.85 vs. -2.11 mmHg) and diastolic blood presure (− 4 vs. -1.86 mmHg) in the vitamin D group compared to the placebo group (all P values < 0.05). Other variables did not significantly change after the intervention.ConclusionBased on our findings, weekly vitamin D supplementation of 50,000 IU for eight weeks in patients with CHD resulted in decreased systolic and diastolic blood pressure, waist circumference and fat percentage. No significant effect on HSP 60, inflammatory markers or lipid profiles was observed.Trial registrationIRCT, IRCT201612122365N14. Registered 12 December 2016.

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