Effects of Anthocyanin Supplementation on Reduction of Obesity Criteria: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Anthocyanins, water-soluble flavonoids that produce red-to-blue pigment in plants, have antioxidant properties and have been developed as a functional food to fight obesity. In randomized controlled trials (RCTs), a systematic review with meta-analysis (SR-MA) was used to investigate these anti-obesity effects. Using search engines (PubMed, EMBASE, Cochrane-library, and CINAHL) and keywords (anthocyanins, BMI, WC, WHR, and inflammatory biomarkers), 11 out of 642 RCTs (28.3-500 mg/day of anthocyanins for 4 to 24 weeks) were included. The results showed a significant reduction in body mass index (BMI) (MD = -0.36, 95% CI = -0.58 to -0.13), but body weight (BW) and waist circumference (WC) did not change. Anthocyanins decreased BMI in the non-obese (non-OB) group in five RCTs (BMI <= 25; MD = -0.40 kg/m(2); 95% CI = -0.64 to -0.16;) but did not affect BMI in the obese (OB) group. A subgroup analysis of six RCTs showed that fewer than 300 mg/day reduced BMI (MD = -0.37; 95% CI = -0.06 to -0.14), but >= 300 mg/day did not. A treatment duration of four weeks for four RCTs was sufficient to decrease the BMI (MD = -0.41; 95% CI = -0.66 to -0.16) as opposed to a longer treatment (6-8 or >= 12 weeks). An analysis of the effect of anthocyanins on the BMI showed a significant fall among those from the Middle East compared to those from Asia, Europe, South America, or Oceania. In conclusion, the anthocyanin supplementation of 300 mg/day or less for four weeks was sufficient to reduce the BMI and BW compared to the higher-dose and longer-treatment RCTs. However, further studies might be conducted regarding the dose- or period-dependent responses on various obese biomarkers.

Automated summary

The study found that supplementation of 300mg or less of anthocyanins per day for four weeks can reduce BMI and weight, with poorer results for higher doses and longer treatments. Additionally, anthocyanins decreased BMI in the non-obese group but did not have a significant effect on the obese group. The research also indicated that individuals from the Middle East showed a more significant decrease in BMI with anthocyanin supplementation.