The Impact of Plant-Based Diets on Inflammation and Immune Function: A Review
DOI:
https://doi.org/10.12775/QS.2025.47.66733Keywords
autoimmune disease, cytokines, gut microbiota, inflammation, metabolic health, vegan diet, vegetarian diet, plant-based dietAbstract
Background:
Chronic low-grade inflammation and immune dysregulation contribute to cardiometabolic, autoimmune and infectious diseases. Dietary patterns, particularly plant-based diets, may influence these processes through metabolic, microbial and nutrient-mediated mechanisms.
Aim:
To summarise current evidence on how plant-based diets affect systemic inflammation, immune activity, gut microbiota–immune interactions and clinical outcomes in infection and autoimmune disease.
Methods:
A narrative review of studies from PubMed, Scopus and Google Scholar, including randomised trials, cohorts, cross-sectional analyses, systematic reviews, meta-analyses and mechanistic or microbiome-focused research. Findings were synthesised qualitatively.
Results:
Healthful plant-based diets are consistently associated with lower CRP, IL-6, TNF-α and other inflammatory markers. Mechanistic studies suggest roles for plant nutrients, microbial short-chain fatty acids and reduced ectopic fat in improving immune regulation. Clinical evidence indicates potential reductions in respiratory infections, asthma exacerbations, COVID-19 severity and some autoimmune conditions. Benefits depend on overall diet quality; processed plant-based diets show limited advantages.
Conclusions:
Plant-based dietary patterns may beneficially modulate inflammation and support immune function, potentially lowering infection-related and autoimmune risks. Evidence remains limited by heterogeneous definitions and short study duration. Well-designed plant-based diets represent a promising non-pharmacological strategy to improve immune and inflammatory health.
References
1. Furman, D., Campisi, J., Verdin, E., Carrera-Bastos, P., Targ, S., Franceschi, C., Ferrucci, L., Gilroy, D. W., Fasano, A., Miller, G. W., Miller, A. H., Mantovani, A., Weyand, C. M., Barzilai, N., Goronzy, J. J., Rando, T. A., Effros, R. B., Lucia, A., Kleinstreuer, N., & Slavich, G. M. (2019). Chronic inflammation in the etiology of disease across the life span. Nature Medicine, 25(12), 1822–1832. https://doi.org/10.1038/s41591-019-0675-0
2. Satija, A., Bhupathiraju, S. N., Spiegelman, D., Chiuve, S. E., Manson, J. E., Willett, W., Rexrode, K. M., Rimm, E. B., & Hu, F. B. (2017). Healthful and Unhealthful Plant-Based Diets and the Risk of Coronary Heart Disease in U.S. Adults. Journal of the American College of Cardiology, 70(4), 411–422. https://doi.org/10.1016/j.jacc.2017.05.047
3. Khalid, W., Arshad, M. S., Ranjha, M. M. A. N., Różańska, M. B., Irfan, S., Shafique, B., Rahim, M. A., Khalid, M. Z., Abdi, G., & Kowalczewski, P. Ł. (2022). Functional constituents of plant-based foods boost immunity against acute and chronic disorders. Open Life Sciences, 17(1), 1075–1093. https://doi.org/10.1515/biol-2022-0104
4. Craddock, J. C., Neale, E. P., Peoples, G. E., & Probst, Y. C. (2019). Vegetarian-Based Dietary Patterns and their Relation with Inflammatory and Immune Biomarkers: A Systematic Review and Meta-Analysis. Advances in Nutrition (Bethesda, Md.), 10(3), 433–451. https://doi.org/10.1093/advances/nmy103
5. Kharaty, S., Harrington, J. M., Millar, S. R., Perry, I. J., & Phillips, C. M. (2023). Plant-based dietary indices and biomarkers of chronic low-grade inflammation: A cross-sectional analysis of adults in Ireland. European Journal of Nutrition, 62(8), 3397–3410. https://doi.org/10.1007/s00394-023-03242-5
6. Kahleova, H., Petersen, K. F., Shulman, G. I., Alwarith, J., Rembert, E., Tura, A., Hill, M., Holubkov, R., & Barnard, N. D. (2020). Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial. JAMA Network Open, 3(11), e2025454. https://doi.org/10.1001/jamanetworkopen.2020.25454
7. Kim, Y. S., Sayers, T. J., Colburn, N. H., Milner, J. A., & Young, H. A. (2015). Impact of dietary components on NK and Treg cell function for cancer prevention. Molecular Carcinogenesis, 54(9), 669–678. https://doi.org/10.1002/mc.22301
8. Link, V. M., Subramanian, P., Cheung, F., Han, K. L., Stacy, A., Chi, L., Sellers, B. A., Koroleva, G., Courville, A. B., Mistry, S., Burns, A., Apps, R., Hall, K. D., & Belkaid, Y. (2024). Differential peripheral immune signatures elicited by vegan versus ketogenic diets in humans. Nature Medicine, 30(2), 560–572. https://doi.org/10.1038/s41591-023-02761-2
9. Calder, P. C. (2021). Nutrition and immunity: Lessons for COVID-19. Nutrition & Diabetes, 11, 19. https://doi.org/10.1038/s41387-021-00165-0
10. Millar, S. R., Navarro, P., Harrington, J. M., Perry, I. J., & Phillips, C. M. (2021). Dietary Quality Determined by the Healthy Eating Index-2015 and Biomarkers of Chronic Low-Grade Inflammation: A Cross-Sectional Analysis in Middle-to-Older Aged Adults. Nutrients, 13(1), 222. https://doi.org/10.3390/nu13010222
11. Carey, M. T., Millar, S. R., Elliott, P. S., Navarro, P., Harrington, J. M., Perry, I. J., & Phillips, C. M. (2024). Plant-based diet adherence is associated with metabolic health status in adults living with and without obesity. European Journal of Nutrition, 63(6), 2235–2246. https://doi.org/10.1007/s00394-024-03399-7
12. Jaceldo-Siegl, K., Haddad, E., Knutsen, S., Fan, J., Lloren, J., Bellinger, D., & Fraser, G. E. (2018). Lower C-reactive protein and IL-6 associated with vegetarian diets are mediated by BMI. Nutrition, Metabolism, and Cardiovascular Diseases: NMCD, 28(8), 787–794. https://doi.org/10.1016/j.numecd.2018.03.003
13. Mrozik, M., Grygorczuk, O., Lipert, A., Białas, A., Kamińska, S., Drygas, W., Rębowska, E., Łegocki, S., Jegier, A., Szmigielska, K., & Kwaśniewska, M. (2025). Not All Plants Are Equal: Diet Quality and Inflammation in Vegans and Vegetarians in Urban Poland. Nutrients, 17(21), 3361. https://doi.org/10.3390/nu17213361
14. Tran, D. Q., Di, K. N., Chi, V. T. Q., & Nguyen, H. T. H. (2024). Evaluating the effects of dietary patterns on circulating C-reactive protein levels in the general adult population: An umbrella review of meta-analyses of interventional and observational studies. British Journal of Nutrition, 132(6), 783–793. https://doi.org/10.1017/S0007114524001648
15. Kahleova, H., Fleeman, R., Hlozkova, A., Holubkov, R., & Barnard, N. D. (2018). A plant-based diet in overweight individuals in a 16-week randomized clinical trial: Metabolic benefits of plant protein. Nutrition & Diabetes, 8(1), 58. https://doi.org/10.1038/s41387-018-0067-4
16. McDougall, J., Bruce, B., Spiller, G., Westerdahl, J., & McDougall, M. (2002). Effects of a very low-fat, vegan diet in subjects with rheumatoid arthritis. Journal of Alternative and Complementary Medicine (New York, N.Y.), 8(1), 71–75. https://doi.org/10.1089/107555302753507195
17. Alwarith, J., Kahleova, H., Rembert, E., Yonas, W., Dort, S., Calcagno, M., Burgess, N., Crosby, L., & Barnard, N. D. (2019). Nutrition Interventions in Rheumatoid Arthritis: The Potential Use of Plant-Based Diets. A Review. Frontiers in Nutrition, 6, 141. https://doi.org/10.3389/fnut.2019.00141
18. Kahleova, H., Znayenko-Miller, T., Motoa, G., Eng, E., Prevost, A., Uribarri, J., Holubkov, R., & Barnard, N. D. (2024). Dietary advanced glycation end-products and their associations with body weight on a Mediterranean diet and low-fat vegan diet: A randomized, cross-over trial. Frontiers in Nutrition, 11. https://doi.org/10.3389/fnut.2024.1426642
19. McAnulty, L. S., Collier, S. R., Landram, M. J., Whittaker, D. S., Isaacs, S. E., Klemka, J. M., Cheek, S. L., Arms, J. C., & McAnulty, S. R. (2014). Six weeks daily ingestion of whole blueberry powder increases natural killer cell counts and reduces arterial stiffness in sedentary males and females. Nutrition Research (New York, N.Y.), 34(7), 577–584. https://doi.org/10.1016/j.nutres.2014.07.002
20. Nantz, M. P., Rowe, C. A., Nieves, C., & Percival, S. S. (2006). Immunity and antioxidant capacity in humans is enhanced by consumption of a dried, encapsulated fruit and vegetable juice concentrate. The Journal of Nutrition, 136(10), 2606–2610. https://doi.org/10.1093/jn/136.10.2606
21. Hosseini, B., Berthon, B. S., Saedisomeolia, A., Starkey, M. R., Collison, A., Wark, P. A. B., & Wood, L. G. (2018). Effects of fruit and vegetable consumption on inflammatory biomarkers and immune cell populations: A systematic literature review and meta-analysis. The American Journal of Clinical Nutrition, 108(1), 136–155. https://doi.org/10.1093/ajcn/nqy082
22. Furusawa, Y., Obata, Y., Fukuda, S., Endo, T. A., Nakato, G., Takahashi, D., Nakanishi, Y., Uetake, C., Kato, K., Kato, T., Takahashi, M., Fukuda, N. N., Murakami, S., Miyauchi, E., Hino, S., Atarashi, K., Onawa, S., Fujimura, Y., Lockett, T., … Ohno, H. (2013). Commensal microbe-derived butyrate induces the differentiation of colonic regulatory T cells. Nature, 504(7480), 446–450. https://doi.org/10.1038/nature12721
23. Smith, P. M., Howitt, M. R., Panikov, N., Michaud, M., Gallini, C. A., Bohlooly-Y, M., Glickman, J. N., & Garrett, W. S. (2013). The microbial metabolites, short-chain fatty acids, regulate colonic Treg cell homeostasis. Science (New York, N.Y.), 341(6145), 569–573. https://doi.org/10.1126/science.1241165
24. Tomova, A., Bukovsky, I., Rembert, E., Yonas, W., Alwarith, J., Barnard, N. D., & Kahleova, H. (2019). The Effects of Vegetarian and Vegan Diets on Gut Microbiota. Frontiers in Nutrition, 6, 47. https://doi.org/10.3389/fnut.2019.00047
25. Hills, R. D., Pontefract, B. A., Mishcon, H. R., Black, C. A., Sutton, S. C., & Theberge, C. R. (2019). Gut Microbiome: Profound Implications for Diet and Disease. Nutrients, 11(7), 1613. https://doi.org/10.3390/nu11071613
26. Wu, G. D., Chen, J., Hoffmann, C., Bittinger, K., Chen, Y.-Y., Keilbaugh, S. A., Bewtra, M., Knights, D., Walters, W. A., Knight, R., Sinha, R., Gilroy, E., Gupta, K., Baldassano, R., Nessel, L., Li, H., Bushman, F. D., & Lewis, J. D. (2011). Linking long-term dietary patterns with gut microbial enterotypes. Science (New York, N.Y.), 334(6052), 105–108. https://doi.org/10.1126/science.1208344
27. Roager, H. M., & Dragsted, L. O. (2019). Diet-derived microbial metabolites in health and disease. Nutrition Bulletin, 44(3), 216–227. https://doi.org/10.1111/nbu.12396
28. Lv, Y., Rong, S., Deng, Y., Bao, W., Xia, Y., & Chen, L. (2023). Plant-based diets, genetic predisposition and risk of non-alcoholic fatty liver disease. BMC Medicine, 21(1), 351. https://doi.org/10.1186/s12916-023-03028-w
29. Kendrick, K. N., Kim, H., Rebholz, C. M., Selvin, E., Steffen, L. M., & Juraschek, S. P. (2023). Plant-Based Diets and Risk of Hospitalization with Respiratory Infection: Results from the Atherosclerosis Risk in Communities (ARIC) Study. Nutrients, 15(19), 4265. https://doi.org/10.3390/nu15194265
30. Hosseini, B., Berthon, B. S., Jensen, M. E., McLoughlin, R. F., Wark, P. A. B., Nichol, K., Williams, E. J., Baines, K. J., Collison, A., Starkey, M. R., Mattes, J., & Wood, L. G. (2022). The Effects of Increasing Fruit and Vegetable Intake in Children with Asthma on the Modulation of Innate Immune Responses. Nutrients, 14(15), 3087. https://doi.org/10.3390/nu14153087
31. Kim, H., Rebholz, C. M., Hegde, S., LaFiura, C., Raghavan, M., Lloyd, J. F., Cheng, S., & Seidelmann, S. B. (2021). Plant-based diets, pescatarian diets and COVID-19 severity: A population-based case-control study in six countries. BMJ Nutrition, Prevention & Health, 4(1), 257–266. https://doi.org/10.1136/bmjnph-2021-000272
32. Merino, J., Joshi, A. D., Nguyen, L. H., Leeming, E. R., Mazidi, M., Drew, D. A., Gibson, R., Graham, M. S., Lo, C.-H., Capdevila, J., Murray, B., Hu, C., Selvachandran, S., Hammers, A., Bhupathiraju, S. N., Sharma, S. V., Sudre, C., Astley, C. M., Chavarro, J. E., … Chan, A. T. (2021). Diet quality and risk and severity of COVID-19: A prospective cohort study. Gut, 70(11), 2096–2104. https://doi.org/10.1136/gutjnl-2021-325353
33. Sharma, S., Di Castelnuovo, A., Cerletti, C., Donati, M. B., de Gaetano, G., Iacoviello, L., & Bonaccio, M. (2023). Diet Quality and Risk of SARS-CoV-2 Infection or COVID-19: A Systematic Review of Observational Studies. Advances in Nutrition (Bethesda, Md.), 14(6), 1596–1616. https://doi.org/10.1016/j.advnut.2023.09.006
34. Acosta-Navarro, J. C., Dias, L. F., de Gouveia, L. A. G., Ferreira, E. P., de Oliveira, M. V. P. F., Marin, F. A., Oliveira, J. V. C., da Silva, A. C., Silva, I. L., Freitas, F. de O., & Soares, P. R. (2024). Vegetarian and plant-based diets associated with lower incidence of COVID-19. BMJ Nutrition, Prevention & Health, 7(1), 4–13. https://doi.org/10.1136/bmjnph-2023-000629
35. Papadaki, A., Coy, E. M., Anastasilakis, D. A., Peradze, N., & Mantzoros, C. S. (2024). The role of plant-based dietary patterns in reducing COVID-19 risk and/or severity in adults: A systematic review and meta-analysis of observational studies. Clinical Nutrition (Edinburgh, Scotland), 43(7), 1657–1666. https://doi.org/10.1016/j.clnu.2024.05.033
36. Müller, H., de Toledo, F. W., & Resch, K. L. (2001). Fasting followed by vegetarian diet in patients with rheumatoid arthritis: A systematic review. Scandinavian Journal of Rheumatology, 30(1), 1–10. https://doi.org/10.1080/030097401750065256
37. Chiba, M., Abe, T., Tsuda, H., Sugawara, T., Tsuda, S., Tozawa, H., Fujiwara, K., & Imai, H. (2010). Lifestyle-related disease in Crohn’s disease: Relapse prevention by a semi-vegetarian diet. World Journal of Gastroenterology, 16(20), 2484–2495. https://doi.org/10.3748/wjg.v16.i20.2484
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2025 Aleksandra Wilczynska, Aleksandra Jurczuk, Sergiusz Romaniuk, Wojciech Kaczmarek, Konrad Bagiński, Piotr Depta, Paulina Bałdyga, Kinga Marciniak
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Stats
Number of views and downloads: 264
Number of citations: 0
