Can Tea consumption reduce risk of colorectal cancer?
Tea is recognized as a chemical preventive agent for some diseases. Previous evidence has already mentioned some protective ingredients in tea that could reduce CRC. However, according to the latest study, tea reduces the risk of colon cancer by 24%, but the estimate is uncertain. The actual effect on risk may range from a reduction of 51% to an increase of 18%. Still, regional and population differences may cause differences, says Dr Yu Huang and colleagues in a recent study published in BMC Gastroenterology.
Tea polyphenols can inhibit tumour development by promoting tumor cell apoptosis, inhibiting proliferation and angiogenesis via regulating signalling pathways like Ras-MAPK. These findings remain controversial. Many studies have shown that tea consumption has no association with a decreased risk of CRC.
Researchers systematically assessed the association between tea consumption and CRC risk in the present meta-analysis from databases like Cochrane Library, Embase, PubMed, and Web of Science. The literature screening was done based on inclusion and exclusion criteria. The random effect model was determined, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.
Key findings of this study are:
- Fourteen articles were included, and a random effect model analyzed the data to explore the association between tea consumption and CRC due to apparent heterogeneity.
- They found no statistically significant association between tea consumption and CRC risk from the combined results of all tests, with an OR of 0.756.
- American subgroup analysis suggested tea drinking might be protective against CRC while data from the UK and Italian subgroups suggested opposite results.
- Considering tea type, green tea had association with a lower CRC risk.
- Based on Sensitivity analysis, the effect on CRC risk can range from a reduction of 51% with RR: 0.49 to an increase of 18% with RR: 1.18
- Excluding any single study, the overall results ranged from 0.73 to 0.86
- There was no significant publication bias between tea consumption and CRC risk (Egger's tests).
They noted that tea consumption may not be significantly associated with CRC development.
They acknowledged limitations in the study warranting discussion and further investigations; this includes high heterogeneity and publication bias.
Reference:
Huang, Y., Chen, Q., Liu, Y. et al. Association between tea consumption and colorectal cancer: a systematic review and meta-analysis of a population-based study. BMC Gastroenterol 23, 294 (2023). https://doi.org/10.1186/s12876-023-02928-8
