Skin cancer from sunlight damage continues to increase in frequency. Nonmelanoma skin cancer risk is increasing due to the following: ozone depletion, climate change, increased sun exposure and the use of UV tanning beds.
Ultraviolet (UV) light damages skin cell DNA. Skin cell DNA damage results in increased frequency of mutations and greater risk of skin cancer. DNA damage can be repaired by a normal pathway called the nucleotide excision repair (NER) pathway. Mutations in this pathway result in a variety of diseases, such as xeroderma pigmentosum, which causes sunlight sensitivity and increases the risk of skin cancer in areas of the body exposed to the sun.
Increasingly, research shows that caffeine from tea and coffee, as normally drunk, has an anti-carcinogenic effect against UV induced DNA damage in mice and in humans. Caffeine by mouth or on the skin increases apoptosis (a natural form of cell death in abnormal cells) to UVB-irradiated skin cells in mice.
Heffernan has identified the way that caffeine works and suggests that inhibition of DNA damage may be therapeutic in nonmelanoma skin cancer. Caffeine induces apoptosis in UV damaged skin cells called keratinocytes. The cells which die from apoptosis are abnormal cells which could have become cancerous. (The keratinocytes are believed to be the origin of nonmelanoma skin cancers.)
CONCLUSION: Coffee or tea caffeine may protect from UVB induced nonmelanoma skin cancer. Caffeine induces apoptosis in skin cells that have damaged DNA due to UVB light.
NOTE: The above statements do not apply to skin melanoma. Ultraviolet light causes 2-4% of all human cancers. Read about nutritional advice in cancer.
Read about the anti-microbial effect of hydrogen peroxide in coffee. Read about the protective effect of fucoxanthin on UVB skin damage.
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