Comparison of the Effects of High versus Low-Polyphenol Dark Chocolate on Body Weight and Biochemical Markers: A Randomized Trial

Abstract

Background: Dark chocolate (DC) has amongst the highest content of polyphenols in foods, but the chocolate processing methods may greatly reduce this amount. Few studies addressed the possible detrimental effects of low polyphenol DC on body weight, glucose metabolism and lipid levels, and the potential role of cocoa flavanols in body weight control. Therefore, this study aimed to determine the effect of DC rich and DC low in polyphenols on BMI, fasting blood glucose, high sensitivity C-reactive protein (hs-CRP) and lipid levels in adults. Methods: Sixty-one participants took part in a randomized parallel trial. Volunteers randomly received 20g daily of either PRDC (polyphenol-rich DC) or of low polyphenol DC (LPDC) for four weeks. Anthropometric measures and blood samples were collected at baseline and after 4 weeks. Results: A significant net increase in BMI (0.17 0.32 kg/m2, p = 0.007), fasting blood glucose (0.44 1.08 mmol/l, p = 0.041) and triglycerides levels (0.13 0.23 mmol/l, p = 0.008) was observed in the low polyphenol DC group following the 4 weeks intervention, while the levels of these parameters did not significantly change in the polyphenol-rich DC group. There was no significant change in hs-CRP levels in both groups. Conclusions: Results show that the intake of PRDC seems to be more metabolically healthy than LPDC intake, and this highlights the potential role of polyphenols in counteracting the negative effects of fat and energy intake in chocolate. The outcomes raise concerns about the polyphenol content and quality of DC products in the market. Further studies are needed to fully investigate the health benefits of dark chocolate intake, compare the effects of different types of chocolate and establish the necessary guidelines of the type and content of polyphenols in the chocolate preparations to ensure their favourable effect on health.