Cocoa Flavonoid-Enriched Diet Modulates Systemic and Intestinal Immunoglobulin Synthesis in Adult Lewis Rats

Abstract

Previous studies have reported that a diet containing 10% cocoa, a rich source of flavonoids, has immunomodulatory effects on rats and, among others effects, is able to attenuate the immunoglobulin (Ig) synthesis in both systemic and intestinal compartments. The purpose of the present study was focused on investigating whether these effects were attributed exclusively to the flavonoid content or to other compounds present in cocoa. To this end, eight-week-old Lewis rats were fed, for two weeks, either a standard diet or three isoenergetic diets containing increasing proportions of cocoa flavonoids from different sources: one with 0.2% polyphenols from conventional defatted cocoa, and two others with 0.4% and 0.8% polyphenols, respectively, from non-fermented cocoa. Diet intake and body weight were monitored and fecal samples were obtained throughout the study to determine fecal pH, IgA, bacteria proportions, and IgA-coated bacteria. Moreover, IgG and IgM concentrations in serum samples collected during the study were quantified. At the end of the dietary intervention no clear changes of serum IgG or IgM concentrations were quantified, showing few effects of cocoa polyphenol diets at the systemic level. However, in the intestine, all cocoa polyphenol-enriched diets attenuated the age-related increase of both fecal IgA and IgA-coated bacteria, as well as the proportion of bacteria in feces. As these effects were not dependent on the dose of polyphenol present in the diets, other compounds and/or the precise polyphenol composition present in cocoa raw material used for the diets could be key factors in this effect.

Impact of cocoa polyphenol extracts on the immune system and microbiota in two strains of young rats

“…First, the influence of cocoa polyphenol intake on the increase in body weight was evaluated during the study period. Although during this period, there was no difference regarding food intake among the experimental groups, those fed with the PC0•2 diet in both rat strains had a lower increase in body weight, a result that is in line with previous studies carried out using conventional cocoa (12,18,20,21) . However, it is worth noting that diets containing non-fermented cocoa with a higher amount of polyphenols did not produce such an effect, suggesting, therefore, that the influence of cocoa on body weight does not depend on cocoa polyphenol content.…”

Effect of a cocoa-enriched diet on immune response and anaphylaxis in a food allergy model in Brown Norway rats

“…Although some studies using polyphenol-enriched diets show a similar effect [25,26], our results with the NFC diet on specific antibodies allow the suggestion that flavonoids are only partially responsible for the attenuating action on Th2-antibody synthesis and other compounds in CC must enhance this anti-allergy effect. In agreement with this suggestion, a previous study in healthy Lewis rats shows that a diet containing 0.8% of polyphenols from NFC produced the same immunomodulatory effect as a diet containing 0.2% of polyphenols from CC [23]. Therefore, the cocoa content of fiber and methylxanthines, which was higher in CC than in NFC, could add to or enhance the action of polyphenols.…”

“…Previous studies concerning the effect of a cocoa diet on the immune system in rats reveal the ability of a cocoa diet to attenuate serum and intestinal immunoglobulin synthesis [2][3][4][5]23,24]. In addition, a diet containing 10% of cocoa in a rat allergy model induced by only an i.p.…”

Effect of cocoa's theobromine on intestinal microbiota of rats

“…The B. acidifaciens has been described as the predominant bacteria responsible for promoting IgA production in the large intestine . This agrees with our current results regarding IgA‐coated bacteria and with previous studies showing lower intestinal IgA with a cocoa diet . On the other hand, CC diet increased the relative abundance of Prevotella sp., which could be due to its polyphenol content since higher numbers in the Prevotella group have been associated with the daily consumption of red wine polyphenols .…”