By: Zixian Zhao – Cancer immunologist at Food Microbiology Academy

In the realm of nutritional science, the connection between diet and immune health has been extensively explored, revealing complex interactions that influence overall health. Recent studies have particularly highlighted the role of fermented foods in modulating the immune system, offering promising avenues for enhancing immune responses and managing various health conditions. This blog article delves into the findings from recent research to unpack how fermented foods can be pivotal in boosting immunity.

Understanding Immunity and Nutrition

Our immune system, a sophisticated network of cells and proteins, serves as the body’s defence against infections. The critical role of nutrition in supporting immune function is well-documented, highlighting that proper nutrients are essential for robust immune health and disease prevention. Unlike simple probiotic supplements, fermented foods sometimes contain live cultures that can function as probiotics,  often bacteria and sometimes yeasts that are integral to gut health—a major player in immunological well-being.  Furthermore, the fermentation process results in a myriad of metabolic compounds, many of which are of much benefit to human health.

Key Findings from Recent Research

Nutritional Control of Immunity: The interaction between diet and immune cell functionality is intricate. According to Veronica De Rosa and her team, dietary components profoundly influence the equilibrium between pro-inflammatory and anti-inflammatory processes, thus impacting health outcomes significantly (De Rosa et al., 2015). 

Nutritional Immunology: Fleur Ponton and colleagues discuss the multifaceted relationship between malnutrition—both under-nutrition and over-nutrition—and immune impairment, which heightens disease vulnerability (Ponton et al., 2011).

Fermented Foods and Immune Modulation: Upasana Sarma and Suchandra Gupta’s research on Indian ethnic fermented foods illustrates how microbial activity in these foods not only fills nutritional voids but also enhances immunity across various populations (Sarma & Gupta, 2022).

Clinical Implications for Cancer Patients: In a pivotal study, Nan Lin et al. found that fermented vegetables could alleviate adverse effects in esophageal cancer patients undergoing combined immunotherapy and chemotherapy, by bolstering nutritional and immunological parameters (Lin et al., 2022).

Fermented Foods in Experimental Models: Investigations into Xeniji, a fermented food product, have demonstrated its potential to bolster antioxidant levels and immune responses in mice, highlighting the health-supportive properties of fermented foods (Zulkawi et al., 2017), at least in a mouse model.

The Science Behind Fermented Foods and Immunity

Fermented foods enhance immunity primarily through their impact on gut health. The fermentation process increases the bioavailability of nutrients, which can better support immune functions. Additionally, the microorganisms that are sometimes present in fermented foods help balance the gut microbiome, a critical element for a healthy immune system. By improving gut health, fermented foods indirectly enhance immune responses and reduce inflammation.

Practical Applications

Incorporating fermented foods into the diet can be a strategic approach to improve immune health. Examples include:

  • Yogurt and Kefir: Rich in lactobacilli, these foods can enhance gut flora and immune function.
  • Kimchi and Sauerkraut: These fermented vegetables are high in vitamins that can help boost the immune system.

Expanding on Fermented Foods and Immune Health

Globally, fermented foods are integral to many traditional diets and are prized for their distinct flavours and health-promoting properties, especially in enhancing immune health. These foods boost immunity largely by improving gut health. The fermentation process enriches the availability of nutrients, thereby supporting the immune system more effectively. Although fermentation does not generate probiotics, it cultivates conditions that encourage the growth of beneficial bacteria, including probiotics, provided they are part of the initial ingredients. By promoting a balanced gut microbiome, fermented foods indirectly bolster immune function and mitigate inflammation.

Future Research Directions in Fermented Foods and Immunity

Future research on fermented foods and immune health should focus on identifying specific probiotic strains with the highest therapeutic potential, understanding the mechanisms through which these foods influence immune cells via the gut microbiota, and assessing the long-term health impacts of their regular consumption. Studies could also explore the role of fermented foods in managing non-communicable diseases through immune modulation and develop personalised nutrition strategies based on individual microbiome differences. This targeted research could lead to more precise dietary recommendations and innovative health solutions.

Conclusion

The intersection of nutrition and immune health is a critical area of study, particularly in the context of increasing health issues related to poor dietary choices. Fermented foods, especially those with a rich probiotic content have health-enhancing properties, and offer a valuable tool for improving immune health. As research continues to unfold, it becomes clear that integrating fermented foods into daily dietary practices can be a beneficial strategy for maintaining health and preventing disease.

In conclusion, while more clinical trials and research are needed to fully understand the optimal types and quantities of fermented foods for health benefits, the current evidence strongly supports their role in promoting a healthy immune system and overall health. Incorporating these foods into a balanced diet, alongside other healthful practices, could potentially lead to better health outcomes and a stronger immune system

References

De Rosa, V., Galgani, M., Santopaolo, M., Colamatteo, A., Laccetti, R., & Matarese, G. (2015). Nutritional control of immunity: Balancing the metabolic requirements with an appropriate immune function. Seminars in Immunology, 27(5), 300–309. https://doi.org/10.1016/j.smim.2015.10.001

Lin, N., Dai, T., Zhou, J., Huang, H., Yun, H., Ding, Z., & Ma, X. (2022). Evaluation of the nutritional index and immunological function of a fermented vegetable for esophageal cancer patients undergoing immunotherapy plus chemotherapy: A randomized controlled trial. Journal of Functional Foods, 99, 105350. https://doi.org/10.1016/j.jff.2022.105350

Ponton, F., Wilson, K., Cotter, S. C., Raubenheimer, D., & Simpson, S. J. (2011). Nutritional immunology: A multi-dimensional approach. PLoS Pathogens, 7(12). https://doi.org/10.1371/journal.ppat.1002223

Sarma, U., & Gupta, S. (2022). An overview on ethnic fermented food and beverages of India: Interplay of microbes, immunity and nutrition. Nutrition and Health, 28(3), 331–339. https://doi.org/10.1177/02601060221085138

Zulkawi, N., Ng, K. H., Zamberi, R., Yeap, S. K., Satharasinghe, D., Jaganath, I. B., Jamaluddin, A. B., Tan, S. W., Ho, W. Y., Alitheen, N. B., & Long, K. (2017). In vitro characterization and in vivo toxicity, antioxidant and immunomodulatory effect of fermented foods; XenijiTM. BMC Complementary and Alternative Medicine, 17(1). https://doi.org/10.1186/s12906-017-1845-6