Results of the randomized, controlled, double-blind, cross-over, clinical trial in healthy young adults showed that consumption of a high-polyphenols cocoa powder led to changes in expression of 98 genes, compared to changes in only 18 genes in the control group.
“The transcriptional response observed in this study was characterized by a moderated differential expression of inflammatory-related genes converging in three major regulatory networks: (1) decreased [reactive oxygen species] production, (2) [calcium] modulation, and (3) inflammatory response modulation,” wrote an international team of researchers report in the European Journal of Nutrition.
“These pathways have been associated with the biological effects of other polyphenols and may contribute to the known benefits of cocoa consumption.”
Cocoa’s benefits
The health benefits of polyphenols from cocoa have been gathering increasing column inches in the national media. To date studies have reported potential benefits for cardiovascular health, skin health, and even brain health.
The majority of science into the potential benefits of cocoa have revolved around cardiovascular benefits of the flavanols (also known as flavan-3-ols or catechins), and particularly the monomeric flavanol (-)epicatechin.
Swiss choc giant Barry Callebaut received authorization in Europe for two health claims relating to cocoa flavanols maintaining the elasticity of blood vessels, and contributing to normal blood flow. The two claims are for 200 mg of cocoa flavanols from cocoa beverages (with cocoa powder) or for dark chocolate (authorized in 2013), and for the same dose for capsules or tablets containing high-flavanol cocoa extract (2015).
Gene expression study
The new study was performed by scientists from the National Institute of Genomic Medicine in Mexico City, the Nestlé Research Centre in Lausanne, Switzerland, Nestlé Institute of Health Sciences, and the Liggins Institute in Auckland, New Zealand.
Twenty healthy young adults were randomly assigned to consume either a single dose of high-polyphenols cocoa powder or maltodextrins (control). This was followed by a one-week “washout” period, and they were then crossed-over into the other group. The cocoa pills used in this study contained about 1.3 g of a commercially available extract, of which about 50% were polyphenols and about 94 mg (-)epicatechin.
“[The] cocoa powder used in the present study contains about four times more procyanidins and eight times more (−)-epicatechin than conventional cocoa,” explained the researchers. “This dose is within the range of previous studies and albeit higher than the average population-based intake, it is considered as achievable by diet.”
Results showed that cocoa consumption led to significant increases in circulating (−)-epicatechin metabolites, but there were slight variations in the profile of metabolites among the subjects.
The cocoa intervention was associated with a changed in the expression of 98 genes, compared with 18 in the control group. These genes were
“In conjunction, differentially expressed genes in this study merge in three major regulatory networks: (1) decreased ROS production [FPR1, IL8, Sestrin 3 (SESN3), CD36, Hemoglobin Subunit Alpha 1/2 (HBA1/HBA2)], (2) Ca2+ modulation [(ADRB2, IL8, IL8RA, IL8RB, FPR1, Protein Tyrosine Phosphatase, Receptor Type C (PTPRC), TPT1 HBA1/ HBA2, ORM1)], and (3) inflammatory response modulation (IL8, PTPRC, TIGIT, TPT1, FPR1, IL8RA and IL8RB). Calcium-mediated ROS modulation by (−)-epicatechin metabolites appears to play a prominent membrane-dependent mechanism by which these substances could exert biological effects,” wrote the researchers.
“This study confirmed that changes in gene expression may occur after a single dose of polyphenols within a short period of time.”
Source: European Journal of Nutrition
Published online ahead of print, doi: 10.1007/s00394-018-1736-8
“Gene expression changes by high-polyphenols cocoa powder intake: a randomized crossover clinical study”
Authors: P.K. Barrera-Reyes, et al.