Meiji-funded study shows consumption of dark chocolate reduces post-meal glucose spike among healthy subjects
Published in the Nutrition journal, findings showed that healthy participants who consumed the chocolate had lower blood plasma glucose levels at 120 minutes, significantly lower than the control group (p<0.01).
This suggest that cacao polyphenol-rich chocolate may have an effect on postprandial glycaemic control, potentially mitigating the onset of many diseases.
Post-meal hyperglycemia (blood sugar levels above 180 mg/dL) is a known contributing factor for the development of type 2 diabetes and cardiovascular diseases.
Cacao is rich in polyphenols such as epicatechin and procyanidins, which have generated considerable interest in the polyphenols’ potential anti-diabetic actions.
In a randomised, crossover study, 48 healthy adult participants were recruited.
The study was conducted over two days, separated by a washout period of three weeks.
After an overnight fast, participants were tasked to consume their test meals within five minutes. The control was 150mL of water, while the treatment meal consisted of 25g of cacao polyphenol-rich chocolate with 150mL of water.
After 15 minutes, blood samples were collected at -15 (baseline), 0, 30, 60, 120 and 180 minutes.
Samples were studied for blood glucose, insulin, and GLP-1 levels.
Following the washout period, participants returned and were given the other test meal, repeating the process.
At 120 minutes, plasma glucose levels was significantly lower in the chocolate group (p<0.01) compared to control.
Serum insulin levels were also significantly higher in the chocolate group (p<0.01) at 0, 30 and 60 minutes, compared to control group.
Plasma GLP-1 concentrations were significantly higher in the chocolate group at 0, 30, 60, 120, and 180 minutes, compared to control.
These findings showed that ingestion of 25g of cacao polyphenol-rich chocolate resulted in a reduction in postprandial plasma glucose elevation due to the enhanced early secretion of insulin and GLP-1.
GLP-1 is a hormone secreted in the small intestine and colon, shown to have the ability to decrease blood sugar levels in a glucose-dependent manner by enhancing the secretion of insulin.
In this study, 25g of chocolate was given. “It might be necessary to evaluate the appropriate amount of cacao polyphenol-rich chocolate for healthy individuals,” researchers said.
“We should also evaluate the effect of cacao polyphenol-rich chocolate on postprandial glycaemic and insulinemic responses in participants with insulin resistance or impaired glucose tolerance since the response to cacao polyphenol-rich chocolate may vary among the participants because of their different background characteristics.”
The cacao polyphenol-rich chocolate contained 635 mg of cacao polyphenols, but researchers did not measure plasma polyphenol concentration in this study.
Another limitation was the use of water as a control. Researchers suggested performing this evaluation using white chocolate which contains nutrients (other than polyphenols) similar to those present in dark chocolate, as a control to determine the effect of cacao polyphenols.
In addition, the outcomes of this study were acute responses, and may differ from real-life conditions such as in a mixed meal intake.
“We need to investigate whether the effects of cacao polyphenol-rich chocolate can have chronic benefits and whether they can be achieved even in cases of eating mixed meals.”
In conclusion, this study portrayed the potential of cacao polyphenol-rich chocolate in managing the spike of postprandial glucose concentrations.
“Effect of cacao polyphenol-rich chocolate on postprandial glycemia, insulin, and incretin secretion in healthy participants”
Authors: Yuka Kawakami, et al.