How Does Coffee Affect the Immune System?

Benedette Cuffari, M.Sc. via News-Medical – As one of the most widely consumed beverages worldwide, coffee is largely consumed for its stimulating effects due to its caffeine concentration. Although previous studies touted coffee as a potential source of health problems, recent studies have found that coffee elicits a wide range of benefits to human health, particularly on the immune system.

What Is the Chemical Composition of Coffee?

When prepared as a beverage, coffee consists of volatile and non-volatile compounds, including carbohydrates, nitrogenous compounds, lipids, vitamins, minerals, phenolic compounds, and alkaloids. Notably, the concentration of certain compounds within coffee depends upon the amount of grounded coffee used to prepare the drink, the roasting and brewing methods, the quality of water used, and the incorporation of other ingredients into the final product.

Caffeine

One of the most notable chemicals in coffee is caffeine, which is chemically known as 1,3,7-trimethylxanthine. This alkaloid, naturally found in coffee beans, stimulates the central nervous system and has also been shown to elicit positive effects on long-term memory.

Within a single cup of coffee, the caffeine content can range from 30 milligrams (mg) to as high as 350 mg. Like any other component of coffee, the caffeine concentration within a single cup of coffee depends upon the type of coffee beans used to prepare the drink, as well as both the brewing and roasting methods.

Aside from its ability to improve focus, memory, and clarity upon consumption, the caffeine within coffee is also associated with several beneficial effects on the immune system. For example, mouse models have shown caffeine to reduce the levels of various inflammatory cytokines including interleukin 6 (IL-6), IL-3, IL-13, and reactive oxygen species (ROS). Similar effects have been observed in obese rats consuming caffeine, which was found to suppress the release of tumor necrosis factor α (TNFα), IL-6, and monocyte chemoattractant protein 1 (MCP-1).

Chlorogenic Acid

Black coffee and, to a greater extent, green coffee are rich in chlorogenic acid (CGA), a polyphenol that plays a primary role in the antioxidant activity of coffee. More specifically, CGA and its isomers capture superoxide anions of hydroxyl radicals, thereby reducing the extent and subsequent impact of damaging oxidative processes. By preventing oxidation and supporting any antioxidant deficiencies within the body, CGA also supports the immune system against the dangerous effective of ROS and other reactive chemicals.

Within a single cup of coffee, the concentration of CGA can range from 70 to 350 mg. The concentration of CGA within a cup of coffee is also primarily dependent upon the method used to roast the coffee beans, as well as the amount of coffee consumed.

Probiotic Delivery

By definition,probiotics are live microorganisms that confer health benefits to the host when consumed in adequate amounts. Some of the primary health benefits associated with the consumption of probiotic species include enhanced immune and gut functions.

One of the most common dietary sources of probiotics is dairy products; however, numerous efforts have been made to develop non-dairy sources of probiotic foods. Recently, researchers have looked towards coffee brews as a delivery source of probiotics.

In particular, non-fermented probiotic coffee formulations have been successfully curated, all the while maintaining the viability of the probiotics against high temperatures normally encountered during the coffee brewing process.

Comparatively, fermented probiotic coffees offer a much more significant health benefit than non-fermented products. In fact, researchers have hypothesized that a successfully fermented probiotic coffee could increase the bioavailability of various endogenous coffee components, including melanoidins and phenolic compounds.

Protection Against Autoimmune Diseases

In addition to caffeine and CGA, some of the other notable components of coffee that elicit various benefits to the immune system include kahweol, cafestol, and arabinogalactans.

Within the innate immune system, these compounds allow coffee to contribute to the cytotoxicity of natural killer cells through their action on C-reactive proteins and toll-like receptors. By enhancing the activity of natural killer cells, coffee may also prevent their degeneration, thereby protecting coffee consumers against various autoimmune diseases.

Comparatively, within the acquired immune system, the caffeine content within coffee potentially suppresses the proliferation of Th1 and Th2 cells. As a result, coffee can reduce the damage caused by the release of cytokines due to overactive T- and B-cells.

The association between coffee consumption and the prevention of autoimmune diseases has been investigated in various types of studies. To this end, these studies have found that coffee intake can reduce the risk of Rheumatoid arthritis, autoimmune thyroid disease, diabetes, multiple sclerosis, psoriasis, autoimmune liver disease, inflammatory bowel disease, and systemic lupus erythematosus.

Conclusions

Over the past several years, various studies have demonstrated that the consumption of coffee has positive effects on the immune system. Nevertheless, daily caffeine intake should not exceed 400 mg/day in adults and 200 mg/day in pregnant and breastfeeding women.

References

• Acikalin, B., & Sanlier, N. (2021). Coffee and its effects on the immune system. Trends in Food Science & Technology 114; 625-632. doi:10.1016/j.tifs.2021.06.023.
• Chan, M. Z. A., & Liu, S. (2022). Coffee brews as food matrices for delivering probiotics: Opportunities, challenges, and potential health benefits. Trends in Food Science & Technology 119; 227-242. doi:10.1016/j.tifs.2021.11.030.
• Farag, M. A., von Bergen, M., Saleh, B. M., et al. (2021). How do green and black coffee brews and bioactive interaction with gut microbiome affect its health outcomes? Mining evidence from mechanistic studies, metagenomics and clinical trials. Trends in Food Science & Technology 118B; 920-937. doi:10.1016/j.tifs.2021.11.004.

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