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

Abstract

Previous studies have demonstrated that cocoa intake decreased Th2 immune-related antibodies in rats. In consequence, we aimed to study in depth this cocoa action, particularly assessing its effect on a rat model of food allergy (FA) and also on an anaphylactic response. The involvement of the intestinal immune system was analyzed to allow the action mechanisms to be investigated. The role of cocoa flavonoids in the antiallergic properties of cocoa was also established. Brown Norway rats were fed either a reference diet or diets containing conventional cocoa (CC) or nonfermented cocoa (NFC). FA to ovalbumin (OVA) was induced and, later, an anaphylactic response was provoked. As expected, the synthesis of anti-OVA IgE and other Th2-related antibodies was inhibited by CC diet. In addition, the release of mast cell protease II after anaphylaxis was partially prevented by CC, although other variables were not modified. The CC diet also attenuated the increase of some Th2-related cytokines released from mesenteric lymph node and spleen cells, and modulated the intestinal gene expression of molecules involved in allergic response. These results demonstrated the local and systemic influence of CC diet. The effects of the NFC diet were weaker than those of CC, suggesting that cocoa components other than flavonoids play a role in cocoa's action. In conclusion, by acting on intestinal and systemic immune functions, a cocoa-enriched diet in rats exhibited a protective effect against FA and partially against anaphylaxis, making this a food of high interest to the fields of health and immunonutrition.

Cocoa Diet and Antibody Immune Response in Preclinical Studies

“…and oral administration of the allergen. The quantification of serum anti-OVA IgG1, IgG2a, and IgE antibodies revealed that the synthesis of these antibodies was completely prevented by the cocoa diet (101) (Table 3). In this study, a product that was richer in cocoa flavonoids was included, but it was not able to totally reproduce the same effects as the conventional cocoa-enriched diet.…”

“…In addition, after anaphylactic shock, the increase of the serum mast cell protease II was partially prevented in the allergic group fed a cocoa diet (101). Nevertheless, other markers of anaphylaxis were not modified by the cocoa intake (body temperature and motor activity), suggesting that its modifications were not enough to prevent the food allergy reaction induced (101).…”

“…Nevertheless, other markers of anaphylaxis were not modified by the cocoa intake (body temperature and motor activity), suggesting that its modifications were not enough to prevent the food allergy reaction induced (101). …”

“…In order to shed light on cocoa’s anti-allergy properties, the expression of some small intestinal genes were quantified (101). The food allergy induction increased the IgA gene expression, an effect that was prevented by a cocoa diet.…”

“…Accordingly, the inhibitory effects of flavonoids on the FcεRI surface molecule or gene expression in vitro were described (116, 117), and the genetic analysis of colon from rats fed cocoa assessed by microarray analysis showed the downregulation of genes involved in pathways related to mast cell activation and degranulation (81). The cytokine production of food-allergic animals was also determined in mesenteric lymph nodes and spleen (101). In these tissues, the food allergy induction increased the secretion of Th2-cytokines, such as IL-4, IL-5, and IL-13.…”