We do not drink only wine/alcoholic beverages, we eat other foods and have particular lifestyle habits. Considering wine/alcohol consumption in the context of the Mediterranean diet and a healthy lifestyle, no increased risk with light to moderate consumption is observed. When reviewing the scientific evidence of the cancer risk with the moderate consumption of alcoholic beverages in isolation, there seems to be a small increase in the risk of breast and colorectal cancer.
There are not enough data to proclaim/support an increased risk of cancer when wine is moderately consumed during the meals and as part of a Mediterranean diet and healthy lifestyle. Such a drinking and dietary pattern seems to result in more health and societal benefits than harm. Moreover, this appears even more pronounced when focusing not only on the life expectancy but also on the increased years without any major diseases such as cardiovascular diseases, diabetes and cancer with this kind of diet and lifestyle.
When assessing the cancer risk of wine consumption or indeed any other food, it is important to consider it within the context of the cultural, drinking and dietary habits. Only then, objective conclusions can be drawn.
Furthermore, a lower total mortality among light to moderate drinkers in comparison to lifetime abstainers is found and cannot be ignored. Not only cancer risk, but also risk of other major diseases causing disability and death needs to be taken into consideration. Coronary heart disease, ischemic stroke, diabetes, and dementia, for example, occur less frequently among moderate drinkers than among non-drinkers.
Regular heavy excessive consumption of alcoholic beverages and binge drinking patterns are risk factors for certain types of cancer, and the risk generally increases with increasing levels of consumption.
In this context, we should remember that the risk of developing cancer involves various risk factors and all cancers that have been associated with alcohol also occur in the absence of drinking.
The overall effect of light to moderate consumption of alcoholic beverages on cancer incidence is less clear and findings are inconsistent. The exception is breast cancer, which also depends on a number of other, more salient factors.
Since cancer is a multi-factorial disease, the cancer risk cannot be evaluated in isolation, and studies suggest that lifestyle factors are important risk factors for cancer. Accordingly, the consumption of alcoholic beverages cannot be accurately evaluated in insolation from the other risk factors.
The Mediterranean Diet (Med Diet), which includes moderate consumption of wine, is considered as one of the healthiest dietary pattern in the world by the WHO, noting that it is directly associated with a lower rate of mortality due to its effects on chronic disease prevention. The Med Diet has been linked with a lower prevalence of several cancers, including breast and colorectal cancer.
Several studies confirm that moderate wine drinking is compatible with a healthy lifestyle (non-smoking, physical activity, normal body weight, balanced diet).
1. Are alcoholic beverages and wine a risk factor for cancers? An ambivalent topic
Cancers are a multifactorial disease and it is increasingly accepted that certain lifestyle choices can affect the risk of developing a cancer. Besides several unmodifiable risk factors (such as age, sex, ethnicity and genetic disposition) which may contribute to an increased risk for most cancers, improvement of lifestyle habits may contribute to a reduced risk of cancer.
According to World Health Organisation (WHO) and the World Cancer Research Fund (WCRF 2018), one third of the cancers could be prevented by adopting a healthy lifestyle (such as avoiding smoking, maintaining a normal body weight, being physically active, avoiding excessive consumption of alcoholic beverages and keeping a healthy dietary pattern) (WHO 2017, WCRF 2018).
In addition, a study performed by the Harvard University further suggested that moderate consumption of alcoholic beverages is one of the five healthy lifestyle factors that reduce the risk of death from all causes, including cancer (Li et al 2018), where the number of low-risk behaviours adopted was inversely related to the risk for mortality.
Furthermore, the Mediterranean Diet (Med Diet) is considered as one of the healthiest diets in the world by the WHO, that notes that it is directly associated with a lower rate of mortality thanks to its effects on disease prevention (WHO Europe 2018).The moderate consumption of alcoholic beverages, particularly wine, is an important component of that diet.
So, recommendations for a “healthy” lifestyle which include a healthy diet and avoidance of alcohol, may be confusing, at least from the Med Diet perspective.
Both, the International Agency for Research on Cancer (IARC) and the World Cancer Research Foundation (WCRF) report that alcohol consumption is associated with an increased risk for certain cancers (WCRF 2018, IARC 2012). Risk is elevated with heavier drinking for all alcohol-associated cancers, with the exception of breast cancer that merits a special consideration (see later). In this context, we should remember that the risk of developing cancer involves various risk factors and all cancers that have been associated with alcohol also occur in the absence of drinking.
Some population studies suggested that ANY consumption of an alcoholic beverage is harmful to health, because of increased cancer risk, regardless of the amount consumed and without assessing the pattern of consumption, the type of alcoholic beverage and other lifestyle factors (Gakidou et GBD collaborators 2018, Wood et al 2018).
These authors concluded that it would be best for our overall health to avoid drinking at all, despite the fact that a reduced risk of myocardial infarction and of all-cause mortality was found, and that cardiovascular diseases are the number one cause of death globally (WHO 2017).
Can we still enjoy a glass of wine with the meal without jeopardizing our health? What does the scientific evidence say regarding a possible cancer risk when wine is consumed moderately within the context (“umbrella”) of a healthy lifestyle and a Mediterranean-style diet?
What do we know – scientific evidence
The chemical substance ethanol/alcohol
The chemical substance ethanol, also referred to as ethyl-alcohol or alcohol per se has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC 1988). This classification is given to agents or exposures where the agency considers there to be sufficient evidence of its carcinogenic effects in humans (IARC 1988).
Two enzymes primarily in the liver (alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH)) are involved in breaking down alcohol to enable the body to eliminate it. In the first step, ADH metabolises alcohol into acetaldehyde, which is a highly toxic chemical substance and known carcinogen. Then in a second step, acetaldehyde is further metabolised by ALDH to another, less active metabolite called acetate, which is then further broken down into water and carbon dioxide for elimination from the body. The damage that acetaldehyde can cause to the cells in the body depends on how quickly it is broken down in the first step into acetate (Stockley et al 2010). Therefore, the faster an individual consumes an alcoholic beverage, the higher the BAC will rise with the respective negative health consequences.