Wine consumption and cancer risk is a sensitive, emotional, and often discussed topic. What does the scientific evidence say? During the 2nd WIC webinar which took place on 30th September, Prof. Ramon Estruch gave a state-of-the-art review on the current scientific data. His presentation, clearly led to believe that simple and general conclusions on the association between the consumption of alcoholic beverages, in particular wine, and the risk of cancer cannot be drawn.
Prof. Ramon Estruch (Doctor of Internal Medicine and Senior Consultant at the Hospital Clinic of Barcelona and Professor at the University of Barcelona) started his presentation by emphasizing that there is no doubt a high consumption of alcoholic beverages increases the risk of several cancers. However, in his opinion, the often publicised and general conclusion “any amount of alcohol causes cancer” is not supported by the current scientific evidence.
It depends on the context
He justified his assessment by explaining that it is important to differentiate and consider the following points: there are different types of cancer, different types of alcoholic beverage (fermented or not fermented, wine or other alcoholic beverages), different drinking patterns (daily versus the same amount only on the weekend) as well as the context of the eating pattern and lifestyle.
This was clearly shown in a large American study which examined the relationship between five lifestyle factors and the mortality risk. Besides not smoking, a normal body weight, healthy eating pattern and regular physical exercise, the fifth beneficial lifestyle factor was the moderate consumption of alcoholic beverages (5-15g of alcohol/day for women and 5-30g/day for men). Those men and women who fulfilled every lifestyle factor had up to 82% reduced mortality risk. According to Estruch, this alone shows that a general assessment about alcoholic beverages is not justified.
Mediterranean eating AND drinking pattern
The most important influencing factor for Prof. Estruch is the eating pattern. With moderate daily wine consumption, a reduced cancer mortality was only observed when the participants of this study also consumed a Mediterranean diet. Similar results were obtained in a meta-analysis, where several studies were summarised, and a Mediterranean dietary pattern was associated with a reduced mortality risk. When analysing the components of the Med Diet, moderate wine consumption was one of the most protective factors. This shows that it is not only important to differentiate between a moderate and high consumption of alcoholic beverages but also whether it is consumed regularly or occasionally, whether it is wine or any other alcoholic beverage, whether it is consumed within a Mediterranean dietary pattern and with or without a meal, Prof Estruch explained.
Furthermore, underreporting, which is particularly common when reporting about one’s own consumption of alcoholic beverages, is another factor that needs to be considered, as it may distort the study results. In one study, the reported amounts of alcoholic beverages consumed by women were 60% below the actual amounts. If such a study then observes an increased breast cancer risk with moderate consumption, then the results are simply wrong because the actual consumption was a lot higher.
Polyphenols in the focus
Prof. Estruch also highlighted the polyphenols in wine which can modulate the cancer risk considerably due to their beneficial effects in all phases of the cancer development. Since wine, more specifically red wine, has considerably more polyphenols than other alcoholic beverages, more pronounced effects of wine are likely.
At the end, he emphasized that for everybody depending on age, gender, existing diseases and risks, it is necessary to do an individual benefit-risk assessment and not only evaluate the alcohol consumption in isolation but also the context. For this, it is also necessary to carry out more high-quality studies which consider both the eating and drinking pattern. In his opinion, only then will it be shown that a moderate wine consumption within a healthy Mediterranean dietary pattern will decrease the cancer risk.
Estruch, R: online Seminar für das Wine Information Council (WIC) am 30.9.2020
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Schwingshackl, L et al.: Adherence to Mediterranean Diet and Risk of Cancer: An Updated Systematic Review and Meta-Analysis. Nutrients 2017;9:1063
Vance, MC et al.: Underappreciated Bias Created by Measurement Error in Risk Factor Assessment – A Case Study of No Safe Level of Alcohol Consumption. JAMA Intern Med 2020;180:459-461