Tangy, tart and sweet! Does citrus intake cause increased risk of skin cancer and melanoma?

As an extreme lover of all things fruit and veg, I find EVERYTHING even more delicious when touched with a lovely citrus tang!  Sugar on my grapefruit?  Absolutely not!!!  Lime in my water?  Yes, please!!!  A squeeze of lemon over everything?  Definitely!  Favorite desert?  Fruit pies.  Favorite cake?  Lemon poppy seed!  B winces as I eat lemons as though they were the sweetest tangerines.  There have been prior reports linking citrus intake with various skin cancers.  Now this ~

Citrus intake and risk of skin cancer in the European Prospective Investigation into Cancer and Nutrition cohort (EPIC).  Mahamat-Saleh, Cervenka, Rahmoun, et al.  Eur J Epidemiol.  2020 Jul 24.

Citrus intake has been suggested to increase the risk of skin cancer. Although this relation is highly plausible biologically, epidemiologic evidence is lacking. We aimed to examine the potential association between citrus intake and skin cancer risk. EPIC is an ongoing multi-center prospective cohort initiated in 1992 and involving ~ 520,000 participants who have been followed-up in 23 centers from 10 European countries. Dietary data were collected at baseline using validated country-specific dietary questionnaires. We used Cox proportional hazards regression models to compute hazard ratios (HR) and 95% confidence intervals (CI). During a mean follow-up of 13.7 years, 8448 skin cancer cases were identified among 270,112 participants. We observed a positive linear dose-response relationship between total citrus intake and skin cancer risk, particularly with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Citrus fruit intake was positively associated with skin cancer risk, particularly with melanoma, although with no heterogeneity across skin cancer types. Citrus juice was positively associated with skin cancer risk, particularly with BCC and SCC, but not with melanoma. Our study suggests moderate positive linear dose-response relationships between citrus intake and skin cancer risk. Studies with available biomarker data and the ability to examine sun exposure behaviors are warranted to clarify these associations and examine the phototoxicity mechanisms of furocoumarin-rich foods.

Hmmmm.....eating the fruit is associated with increased incidence of melanoma, but citrus juice is not???  Hold up!  Y'all aint got juice in yo fruit????  Well, either this is bunk in general or there is some component in the fruit, that is not included in processed (I presume) juice.  Still, overall - if there was substantial risk of melanoma with citrus intake, one would expect to see increased rates of melanoma in areas with increased citrus consumption - which according to a little research happens to be India, Pakistan, China, Mexico and Brazil.  However, the areas with the highest rates of melanoma are New Zealand, Australia, Switzerland, the Netherlands, Denmark and Sweden.  Clearly, melanin content in the residents' skin is vastly different in those areas as well.  So - what does all this mean?  "No se!"

"Don't drink.  Don't smoke.  What do you do?"  Why, I run and eat lemons!  How bout you?

For what it's worth.  - c

Late addition, 8/18/2020 - Now, there's this:

Association between Citrus Consumption and Melanoma Risk in the NIH-AARP Diet and Health Study . Melough, Sakaki, Liao, et al.  Nutr  Cancer 2020 Aug 13.  

It has been hypothesized that consumption of citrus, a group of foods particularly rich in a class of photoactive compounds known as furocoumarins, may increase the risk of malignant melanoma. However, this hypothesis has not been rigorously studied in a general sample of US men and women. This study examined the relationship between citrus intake and melanoma risk in subjects of the NIH-AARP Diet and Health Study. Among 388,467 adults, 3,894 melanoma cases were identified during a median follow-up of 15.5 years. After adjustment for relevant potential confounders, total citrus consumption was not significantly associated with melanoma risk in this cohort. Among those with higher estimated exposure to ultraviolet radiation, and among those aged 60+ years at baseline, there were significant trends toward increased melanoma risk associated with whole citrus fruit consumption , but the hazard ratios of the top consumers (2+ cups per week) vs. nonconsumers were nonsignificant. Further research is needed to explore associations of citrus with melanoma risk among older adults and those with high sun exposure.

So there you have it.  For now.  - c