Plant-based eating may dial down a key inflammation marker

Chronic low-grade inflammation, sometimes called inflammageing, accelerates many age-related diseases, and C-reactive protein is one of the best validated blood markers of it, as well as an independent predictor of cardiovascular events. Observational studies have linked plant-based dietary patterns, which supply more antioxidants and unsaturated fats than omnivorous diets, to lower circulating CRP. But people who eat plant-based tend to differ in many other ways, so whether the diet itself causes lower CRP has remained unclear. This analysis pooled the controlled trial evidence to test the question more directly.

The authors searched MEDLINE, Embase and Web of Science for controlled clinical trials comparing plant-based dietary patterns against omnivorous ones with CRP as an outcome. From 2962 studies identified, only 7 trials qualified, generating eight data sets with 541 participants of median age 55 years. Differences in CRP were pooled using a random-effects model, and the team assessed risk of bias, how much the trials disagreed with each other, and how sensitive the result was to individual studies.

Across all 7 trials, plant-based dietary patterns were associated with CRP concentrations 1.13 mg/L lower than the omnivorous comparisons, a statistically significant difference. Because some trials also prescribed exercise, the authors reran the analysis without them, and the effect held at 0.94 mg/L lower. However, the trials disagreed with each other considerably, and the authors rate the certainty of the evidence as low. Their conclusion is deliberately cautious: plant-based patterns may lower CRP, but further evidence gathering is required to validate the finding.

The finding moves the plant-based and inflammation story a step beyond observational links, since these were controlled trials rather than surveys of what people already ate. It is consistent with the idea that diets richer in antioxidants and unsaturated fats damp low-grade inflammation. But seven trials is a slim base, the studies varied widely, and low certainty means the estimate could shift as evidence accumulates. Which specific features of plant-based eating drive the effect, and for whom, remain open questions.

If you already lean plant-based, this is a modest piece of supporting evidence that the pattern may be doing something useful to background inflammation, a process tied to cardiovascular risk and ageing. It is not proof, and it says nothing about any particular food or supplement, only whole dietary patterns compared in trials. The sensible reading is that the inflammation case for plant-forward eating looks plausible and is getting stronger, but is not yet settled.