Can your favorite snack protect against COVID-19?

Natural compounds—such as flavonoids, alkaloids, polyphenols, and anthocyanins—have long been used as treatments for viral infections and immunoprotection. For instance, low doses of resveratrol, a well-known polyphenolic compound found in red wine, have been shown to stimulate and strengthen the immune system. Some researchers have also suggested that resveratrol may be efficacious against some viruses, including herpes simplex virus and Epstein–Barr virus. Like resveratrol, naturally occurring compounds in cocoa, the primary ingredient in chocolate, have demonstrated promising antiviral activity against a broader range of viruses—such as hepatitis, herpes simplex, HIV, and influenza—in clinical trials. But what about SARS-CoV-2, the devastating novel coronavirus? Could something as simple and delicious as cocoa help defend against the dangerous respiratory virus taking the world by storm?

In light of the COVID-19 pandemic, it’s intriguing to wonder whether any of cocoa’s natural compounds—most widely consumed in chocolate products—may have a role in the battle against the novel pathogen. In particular, anthocyanins, which are a type of phytochemical found in cocoa, may harbor special potential in augmenting antiviral immune responses. Here’s a closer look at some recent research on the antiviral effects and immune-boosting properties of cocoa.

Immunoprotective effects

Cocoa consumption has been shown to have a positive impact on the immune system’s inflammatory innate response, as well as the systemic and intestinal adaptive responses. Basic science research has also proven that a diet rich in cocoa enhances T-cell function and leads to the formation of systemic and gut antibodies. 

In murine models, cocoa has been observed to cause changes in the lymphocyte composition of secondary lymphocyte tissues and T-cell–secreted cytokines, suggesting that cocoa may inhibit the function of T-helper type 2 cells (which contribute to the development of allergic disorders and diseases like asthma). Cocoa could also alter the function of gut-associated lymphoid tissue by modulating IgA secretion, as well as intestinal microbiota, the balance of which is essential for immune health.

Antiviral effects

Anthocyanins are antioxidants found in the cocoa seeds of Theobroma cacao, or the cacao tree. Anthocyanins are polyphenolic pigments that give leaves, flowers, and fruits their colors, and they play various roles in the life of a plant. For instance, anthocyanins in petals help attract pollinators while their presence in fruits and seeds helps with seed dispersal. They also act as feeding deterrents and protect against damage caused by ultraviolet radiation.

Among their various beneficial properties, anthocyanins are mighty antioxidants that scavenge free radicals, mitigate the effects of reactive oxygen species, and lower lipid peroxidation. As you know, during the course of infection, white blood cells are activated and free radicals are produced; the antioxidants in cocoa can neutralize these radicals.

According to the results of a review article published in Frontiers in Pharmacology, cyanidin-3-arabinoside and cyanidin-3-galactoside—the two main anthocyanins found in cocoa seeds—elicit dose-dependent activity against influenza A, influenza B, and avian influenza viruses. Such action was due to cocoa’s inhibition of the adsorption phase of the viruses.

When researchers looked more closely at human models, titers of neutralizing antibodies and natural killer cell activity against influenza A virus was heightened after ingestion of a cocoa seed extract containing cyanidin-3-arabinoside and cyanidin-3-galactoside. Furthermore, anti-HIV activity was demonstrated in cacao husk extract.

Overall, the researchers concluded that “T. cacao is a promising plant containing anthocyanins to tackle viral infections.”

Vaccine enhancement

In addition to bolstering the immune system’s functionality and defenses, cocoa may also enhance the efficacy of vaccination for some viruses. 

In one clinical trial, for instance, an experimental group consumed cocoa for 3 weeks before and after vaccination for H1N1 influenza virus. Neutralizing antibody titers against the virus were compared with those of a control group that did not consume cocoa. Although the antibodies were significantly higher in both groups, the extent of the increase was not significantly different between the groups. However, natural killer cell activity was substantially increased in the cocoa-intake group. 

“Drinking cocoa activates natural immunity and enhances vaccination-induced immune response, providing stronger protection against influenza virus infection and disease onset,” concluded the researchers.

While a vaccine for COVID-19 is still in the works, it seems that a little bit of cocoa may go a long way in amplifying the prophylactic’s efficacy once it finally becomes available. 

Dose and side effects

One admirable quality of the potential use of cocoa in the physician’s armamentarium against COVID-19 and other viruses is its favorable safety profile. While other experimental treatments like remdesivir and hydroxychloroquine carry the risk of adverse events, cocoa and chocolate consumption are relatively safe (and tasty) in most people. 

As far as how much to consume—well, that answer is not as clear cut. Studies have investigated the efficacy of cocoa-enriched diets ranging from 10% cocoa extract intake weekly to daily consumption of high-cocoa beverages (about 500 mg) to twice-daily doses of 10-g cocoa powder—all resulting in positive outcomes. Without a definitive recommendation, it’s probably a good idea to limit your cocoa consumption, given that most cocoa-containing products—like chocolate and hot cocoa mixes—are high in sugar and fat. Dark chocolate often contains a higher percentage of cocoa than milk chocolate (about 75% vs 25%), and researchers have shown that just ≤ 1 standard bar of chocolate weekly can offer a host of health benefits.