Summary: In a secondary analysis of a year-long trial in overweight and obese postmenopausal women, high-dose green tea extract did not significantly reduce any inflammatory marker compared with placebo, a robust null result.
PICO Summary
| Element | Detail |
|---|---|
| Population | 97 postmenopausal women with overweight or obesity; secondary analysis of the Minnesota Green Tea Trial (randomised, double-blind, placebo-controlled), USA. |
| Intervention | High-dose green tea extract providing about 843 mg EGCG per day for 12 months. |
| Comparison | Identical placebo capsule for the same duration. |
| Outcome | No significant difference between groups in change in C-reactive protein (p=0.24), interleukin-6 (p=0.59), or TNF-α (p=0.36), and no interaction with time (all p>0.40). COMT genotype did not modify the effect. The supplement was well tolerated. |
Green Tea Extract & Inflammation
RCT secondary analysis · postmenopausal · 12 months
High-dose green tea extract for one year did not lower CRP, IL-6, or TNF-α versus placebo. A consistent null across all three markers, unmodified by COMT genotype.
Expert Commentary
This is a clean and useful negative study, and its value lies precisely in being negative, since it tests a popular anti-inflammatory claim for green tea extract under reasonably rigorous conditions and finds nothing. The null result is consistent across all three cytokines rather than selective, and even accounting for COMT genotype, which influences EGCG metabolism, made no difference, which strengthens confidence that this is a real absence of effect rather than a missed subgroup. It fits a recurring pattern in supplement research, where laboratory and animal promise fails to translate to human clinical benefit. I would keep the honest limitations in view: this was a secondary analysis of a trial designed for other endpoints, 97 participants may miss a small effect, the women were generally healthy with not-markedly-elevated baseline markers, raising a possible floor effect, and background tea intake was not tightly controlled. Can I use this with my patients? Yes, as clear guidance. I would not recommend green tea extract supplements to reduce inflammation in this population, and would counsel patients using them for that purpose about these findings, while redirecting to the interventions that do work, weight reduction, physical activity, and dietary-pattern change, and noting this does not argue against ordinary green tea as a beverage.
References
Cunningham A, Gomes A, Meng L, Shapses S, Byham-Gray L, Samavat H. Effects of green tea extract supplementation on inflammatory cytokines among postmenopausal women with overweight or obesity—a secondary analysis of a randomized controlled trial. Nutrients. 2026;18(1):143. doi:10.3390/nu18010143