“The first key finding is that overall, there is no difference by wine type in terms of cancer risk,” said Eunyoung Cho, corresponding author of the study and associate professor of epidemiology and of dermatology at Brown. “The second key finding may be that for skin cancer, there is a positive association with white wine, but not with red wine.”
Cho discussed the study’s findings with the Globe.
Q. What was the focus of your study, “Consumption of Red Versus White Wine and Cancer Risk: A Meta-Analysis of Observational Studies?”
Eunyoung Cho: We conducted this study as a meta-analysis, which means we put together a lot of published papers (42 studies) that looked at red wine and white wine separately. We wanted to see whether the association between red wine and cancer is different from white wine and cancer. It’s very well-known that alcoholic beverages – including wine – can increase cancer risk. There is no doubt about that. But then there are not a lot of studies looking at red and white wine separately. That was the focus of the research.
Statistically, what was the difference in cancer risk between red and white wine?
Cho: For red wine, the relative risk for the highest versus lowest level of intake was .98, which was not significant. And for white wine it was 1.00, which was not significant.
Which cancer types were examined in the study?
Cho: We were able to look at breast, skin, ovarian, prostate, lung, kidney, urinary tract, and colorectal cancers, separately for red versus white wine. None of those cancers had a different association except for skin cancer. For skin cancer, only white wine was significantly related to increased risk.
Why skin cancer?
Cho: It’s unclear. Our original hypothesis that we wanted to test in this study was whether red wine versus white wine is different. And that’s largely because red wine has some antioxidant compounds. One of the major ones is resveratrol (a natural compound found in the skin of some plants), which is known to reduce cancer in animal studies. Red wines have a lot more resveratrol. People postulate that red wine may be better in terms of cancer risk, however, overall, we didn’t find that it was.
Did you find any relationship between cancer risk and the amount of wine consumed, given claims, for example, that a glass a day is good for heart health?
Cho: We could only compare low intake versus high intake, because each of the studies used different comparisons.
Did the study consider outside factors, such as exposure to ultraviolet sunlight, smoking, or consumption of other alcohols such as beer or whiskey?
Eunyoung Cho: We cannot conduct that kind of analysis, but if any of the studies adjust for sunlight exposure, if they adjust for other types of alcoholic beverages, we just use the data. We are not able to separately take into account confounding factors, such as sunlight exposure, in this type of analysis.
Did the study find any difference between men and women?
Eunyoung Cho: There was no statistical difference. But when we looked at wine consumption, the association between wine and cancer risk was significant only in women. However, the sample size for women was larger. Statistical significance relies on the sample size. When we look at red wine and white wine in men and women separately, for women, red wine was not related to overall increased cancer risk, but white wine was.
What is the compositional difference between red and white wine that makes people think they present different risks for cancer?
Cho: Red wine contains a lot more grape skin, and the skin contains more antioxidant compounds like resveratrol. That’s how people hypothesize that red wine will be more beneficial than white wine. Based on our analysis, red wine is not any better than white, except when it comes to skin cancer.
Were there any limitations to this study that you couldn’t account for?
Cho: As this is a meta-analysis, we extract the data from published papers. So, 42 published papers and we were not able to adjust for certain things. … We didn’t have a large sample size for many cancer sites. We didn’t have data on some cancer sites such as cancers of the oral cavity, pharynx, larynx, esophagus, or liver.
Would you make any public health, or dietary, recommendations based on the study?
Cho: At this stage, I would consider our findings an interesting observation rather than a basis for public health recommendations. Our results suggest that drinking red wine may not be any better than drinking white wine in terms of cancer risk. It’s reasonable to say we shouldn’t view red wine as a healthier option than white wine.
The Boston Globe’s weekly Ocean State Innovators column features a Q&A with Rhode Island innovators who are starting new businesses and nonprofits, conducting groundbreaking research, and reshaping the state’s economy. Send tips and suggestions to reporter Alexa Gagosz at alexa.gagosz@globe.com.
Carlos Muñoz can be reached at carlos.munoz@globe.com. Follow him @ReadCarlos and on Instagram @Carlosbrknews.
