According to an analysis of clinical trials conducted by researchers at the University of Warwick, consuming plant-based foods may help lower a major inflammation marker in the body.*
The study, which appeared in the journal Nutrition, Metabolism and Cardiovascular Diseases, represents the first systematic review and meta-analysis of randomized controlled trials assessing whether plant-forward dietary patterns impact C-reactive protein (CRP) levels, a widely used marker for systemic inflammation.
Low-grade, persistent inflammation, also known as “inflammaging,” is increasingly recognized as a contributor to age-related conditions such as cardiovascular disease, type 2 diabetes, and certain cancers.
Out of nearly 3,000 studies initially identified as measuring the effect of a plant-based diet on CRP levels, only seven met the strict inclusion criteria for randomized controlled trials. The analysis of these trials, involving 541 individuals, demonstrated that a plant-based diet (including vegan, vegetarian, and whole-food plant-based diets) was associated with significantly lower CRP levels when compared to an omnivorous diet.
The study’s lead author, Luke Bell, a student at Warwick Medical School, stated: “We found that swapping an omnivorous diet for one rich in plant foods reduced CRP levels by an average of 1.13 mg/L. CRP is a key signal of inflammation within the body, and lower readings generally mean less background inflammation present. CRP levels are also frequently used to gauge cardiovascular risk, with levels below 1 mg/L considered low risk and above 3 mg/L considered high risk. Therefore, a CRP reduction like the one we observed could shift individuals into lower-risk categories.”
Plant-centric diets are typically abundant in fruits, vegetables, whole grains, legumes, nuts, and seeds, and generally provide higher amounts of fiber, antioxidants, and unsaturated fats compared to diets featuring more animal products. The researchers speculate that these nutrients, alongside lower intake of saturated fats, may partially account for the anti-inflammatory effect.
“It is already known that plant-based diets improve major cardiovascular risk factors such as blood pressure, LDL cholesterol, and body weight. Our findings point to an additional mechanism through which these diets might reduce the risk of chronic diseases,” added study co-author Joshua Gibbs from the University of Warwick. “When studies involving structured exercise programs were excluded, the risk reduction persisted, although it was somewhat smaller. The greatest reduction was seen in trials that paired a plant-based diet with increased physical activity, suggesting that lifestyle changes may have the most impact when implemented together, although further research is needed to confirm this.”
Prior observational studies had linked these diets to lower inflammation and reduced chronic disease risk, but unlike earlier reviews that relied heavily on observational data, this analysis focused exclusively on randomized controlled trials, which are regarded as the gold standard for establishing cause and effect.
“It is important to note that out of nearly 3,000 studies screened for this review, only seven met the inclusion criteria for randomized controlled trials. While the results suggest a plausible effect of plant foods on reducing inflammation, given the limited number of large-scale studies, we must encourage the generation of more robust evidence to support these preliminary findings,” concluded study co-author Professor Francesco Cappuccio from Warwick Medical School.
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