Reducing Risk of Skin Cancer and Diabetes - New Tea Research Review from 2019

Two epidemiological studies were published this past year looking at large populations and assessing potential correlations between tea consumption and reduced risk for certain diseases, most notably nonmelanoma skin cancer (NMSC), and diabetes mellitus. Both studies showed statistically significant, dose dependent relationships between drinking tea/caffeine and reduced incidence of NMSC, and type 2 diabetes mellitus (Chen et al., 2019; Oh et al., 2019).

These studies both looked at middle age, Asian populations, adding to previous data-sets showing people of European descent that consume more caffeine (from either tea and/or coffee) may be at less risk for nonmelanoma skin cancer (NMSC) than those who drink less or no caffeine.

Caffeine Appears to Reduce Risk of Skin Cancer:

Oh et al. (2019) discussed the results of their analysis, pointing to the experimental research that explains the physiological protection provided by caffeine against skin cancer cell proliferation and how it matches other epidemiological data; they explain in detail:

Experimental studies have provided evidence of an in vitro proapoptotic effect of caffeine on keratinocytes. Previous experimental studies have reported that caffeine has the ability to induce apoptosis in UV-damaged keratinocytes and prevent UV-induced carcinogenesis in animals. This photoprotective effect of caffeine has also been seen in cultured human keratinocytes. Caffeine inhibits the UV B-induced formation of thymidine dimers and may enhance apoptosis of precancerous cells through p53-dependent and p53-independent biologic pathways. One of these proapoptotic pathways mediated by caffeine includes the inhibition of the protein ATR serine/threonine kinase (previously known as ataxia telangiectasia and Rad3 related), which has preferential binding to UV-damaged DNA to obstruct premature chromatin condensation. Our finding of a protective association of coffee and caffeine intake with basal cell carcinoma (BCC) is consistent with all previous prospective studies in Australia, United States, and Europe that have examined the association between caffeinated coffee and risk of BCC. Conversely, decaffeinated coffee has not found to be associated with risk of BCC. (p. 399)

In other words, repeated studies have shown, in both laboratories, and in real-world analysis of large populations, that caffeine intake is significantly correlated with reduced risk of basal cell carcinoma and squamous cell carcinoma.