Research support

Dietary Polyphenols and impact on energy expenditure in obese

grant holder
Jasper Most
university
- Maastricht University, The Netherlands

The present study investigated the potential additional and synergistic effects of short-term supplementation of two combinations of polyphenols on energy expenditure (EE) and substrate metabolism in overweight subjects.

Background and Objectives: The epidemic of obesity and its related metabolic diseases is based on a misbalance between energy intake and energy expenditure. One of the underlying causes of this misbalance might be an impaired regulation of lipid oxidation (metabolic inflexibility), which is associated with obesity and insulin resistance. Obviously, therapeutic approaches to increase energy expenditure and to reduce obesity-related metabolic complications might be a valuable tool to counteract the development of obesity-related insulin resistance and cardiovascular diseases. In rodent studies dietary supplements, such as Resveratrol, Epigallocatechin-gallate and soy isoflavones, have been proven to be effective to improve energy balance and insulin sensitivity. More recently, research has indicated that these polyphenols may modulate mitochondrial function, substrate metabolism and energy expenditure in humans.

The present study investigated the potential additional and synergistic effects of short-term supplementation of two combinations of polyphenols on energy expenditure (EE) and substrate metabolism in overweight subjects.

Subjects and Methods: 18 healthy overweight volunteers (9 women, 9 men; age 35±2.5 yrs; BMI 28.9±0.4 kg/m2) participated in a randomized, double-blind cross-over trial. Combinations of Epigallocatechin-gallate (E, 282mg/d) + Resveratrol (R, 200mg/d), and E+R + 80mg/d soy isoflavones (S), or placebo capsules (PLA) were supplemented twice daily for a period of 3 days. On day 3, circulating metabolite concentrations, energy expenditure and substrate oxidation (using indirect calorimetry) were measured during fasting and postprandial conditions for 6 hours (high-fat-mixed meal (2.6MJ, 61.2 E% fat)).

Results: Short-term supplementation of E+R increased resting EE, whereas both E+R and E+R+S increased 2-4h-postprandial EE compared with PLA. Metabolic flexibility, calculated as the postprandial increase to highest respiratory quotient (RQ) achieved, tended to be improved by E+R compared with PLA and E+R+S only in men. E+R+S significantly increased fasting plasma free fatty acid and glycerol concentrations compared with PLA. Besides an increase in fasted leptin concentrations after E+R supplementation in women, hormone (adiponectin, catecholamins) and cytokine (Interleukin-6, Interleukin-8, Tumor necrosis factor-α) concentrations were not affected by both supplementation periods

Conclusions: We demonstrated for the first time that combined E+R supplementation for 3 days significantly increased fasting and postprandial EE. Assuming the increase achieved in this study by supplementing E+R maintains during long-term supplementation without counter-regulatory effects, this may result in a 1.4 kg weight loss over a period of 6 months. According to findings in the US Diabetes Prevention Program, every kilogram of weight loss reduces the risk for developing diabetes by 16%.

In addition, we observed an improved metabolic flexibility in men but not women, which may indicate improved insulin sensitivity. Addition of soy isoflavones partially reversed these effects possibly due to their higher lipolytic potential. The present findings may imply that long-term supplementation of these dosages of epigallocatechin-gallate combined with resveratrol may improve metabolic health and body weight regulation.

In fact, to investigate this potential of long-term benefits, we performed a 3-month intervention study, in which we investigated the effects of E+R-supplementation on insulin sensitivity, body weight regulation and mitochondrial function in overweight/obese subject. The results of this study are currently being analyzed.

Publication:

J Most, GH Goossens, JWE Jocken and EE Blaak. Short-term supplementation with a specific combination of dietary polyphenols increases energy expenditure and alters substrate metabolism in overweight subjects. International Journal of Obesity (2014) 38, 698–706.