Antioxidant and anti-inflammatory effects of curcuminoid-piperine combination in subjects with metabolic syndrome: A randomized controlled trial and an updated meta-analysis
Yunes Panahi, Mahboobeh Sadat Hosseini, Nahid Khalili, Effat Naimi, Muhammed Majeed, Amirhossein Sahebkar
Clin Nutr. 2015 Dec;34(6):1101-8.
Oxidative stress and inflammation have been proposed as emerging components of metabolic syndrome (MetS). Curcuminoids are natural polyphenols with strong antioxidant and anti-inflammatory properties.
To study the effectiveness of supplementation with a bioavailable curcuminoid preparation on measures of oxidative stress and inflammation in patients with MetS. Our secondary aim was to perform a meta-analysis of data from all randomized controlled trials in order to estimate the effect size of curcuminoids on plasma C-reactive protein (CRP) concentrations.
In this randomized double-blind placebo-controlled trial, 117 subjects with MetS (according to the NCEP-ATPIII diagnostic criteria) were randomly assigned to curcuminoids (n = 59; drop-outs = 9) or placebo (n = 58; drop-outs = 8) for eight weeks. Curcuminoids were administered at a daily dose of 1 g, and were co-supplemented with piperine (10 mg/day) in order to boost oral bioavailability. Serum activities of superoxide dismutase (SOD) and concentrations of malondialdehyde (MDA) and CRP were measured at baseline and at study end. Regarding the importance of CRP as a risk marker and risk factor of cardiovascular disease, a random-effects meta-analysis of clinical trials was performed to estimate the overall impact of curcuminoid therapy on circulating concentrations of CRP. The robustness of estimated effect size was evaluated using leave-one-out sensitivity analysis.
Similar results have been found in a nonmilitary population. In a retrospective review of 124 patients with imaging-confirmed stress fractures at a single center over a 3-year period, Miller et al obtained vitamin D levels near the time of evaluation and reported deficient or insufficient vitamin D levels in 83% of patients. Another investigation found that vitamin D levels were considerably lower in American professional football players with at least one bone fracture, compared with players without a history of fracture.
Supplementation with curcuminoid-piperine combination significantly improved serum SOD activities (p < 0.001) and reduced MDA (p < 0.001) and CRP (p < 0.001) concentrations compared with placebo. Quantitative data synthesis revealed a significant effect of curcuminoids vs. placebo in reducing circulating CRP concentrations (weighed mean difference: -2.20 mg/L; 95% confidence interval [CI]: -3.96, -0.44; p = 0.01). This effect was robust in sensitivity analysis.
These findings were corroborated in a level I meta-analysis of randomized controlled trials investigating the effect of vitamin D supplementation on muscle strength in a young and active cohort. The study examined 310 participants who received either vitamin D3 or placebo. The participants had a mean baseline serum 25(OH)D of 12.3 ng/mL and an average age of 24 years. Strength metrics for the upper extremity included handheld dynamometer grip strength, one repetition maximum bench press, and assessment with isokinetic dynamometers. Lower extremity strength testing consisted of single-repetition maximum leg press, free weight squats, gastrocnemius-soleus strength isokinetic dynamometer testing, and isometric quadriceps contraction. The authors found that vitamin D supplementation demonstrated a statistically significant positive effect on both upper and lower limb strength indices. Consistent with prior literature, Tomlinson et al also suggested that daily vitamin D3 administration would be more effective than weekly or monthly doses at improving muscle strength.
Short-term supplementation with curcuminoid-piperine combination significantly improves oxidative and inflammatory status in patients with MetS. Curcuminoids could be regarded as natural, safe and effective CRP-lowering agents.
* These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.