Moderate drinking is often advocated for its health ‘benefits’, specifically with regard to its apparent ability to reduce the risk of cardiovascular conditions such as heart attacks and stroke. However, whatever benefits alcohol may have with respect to cardiovascular disease can be diluted through its ability to increase the risk of other conditions such as cancer.

One form of cancer that seems to have quite a strong association with alcohol consumption is breast cancer. Several studies have found that even quite moderate alcohol intake is associated with significant increase in breast cancer risk. Recently, a study published in the American Journal of Epidemiology found that drinking 30 g or more of alcohol a day (the equivalent of less than half a bottle of wine a day) was associated with a 32 per cent increased risk of breast cancer, and a 43 per cent increased risk of severe (invasive) breast cancer compared to women drinking no alcohol at all [1].

Such studies show that alcohol consumption is associated with increased breast cancer risk, but do not prove that it’s alcohol that is the cause of this increased risk. However, there are known to be a number of ways in which alcohol could increase breast cancer risk [2]. For instance, a breakdown product of alcohol known as acetaldehyde may have cancer promoting effects. Alcohol also has the capacity to affect the way the hormone oestrogen acts in the body, and this hormone is known to play a role in the development of many cases of breast cancer.

Another way in which alcohol may increase breast cancer risk concerns its ability to reduce levels of the nutrient folate in the body. Folate deficiency has been shown to be important for the normal functioning of DNA – something which would be expected to help protect against cancer.

The importance of this is that there is some evidence that higher levels of folate in the diet seems to mitigate against the apparent ability of alcohol to increase breast cancer risk. In one study published in 2005 in the British Medical Journal drinking 40 g or more of alcohol a day was associated with a doubling in risk of breast cancer in women consuming 200 mcg of folate a day. On the other hand, for women consuming 400 mcg of folate a day, this level of alcohol consumption was not associated with an increased risk of breast cancer [3].

While I do not share the enthusiasm for alcohol that some health advisors have, I am not dead against it either. I drink, and don’t believe that everything that passes our lips each day should be dictated by its likely health effects. However, I do think that if we are going to consume alcohol, we might want to take steps to protect ourselves from any adverse effects it may have on the body.

One simple way to do this is to match each alcoholic drink with a glass of water. In addition, women keen to do what they can to protect themselves of breast cancer might want to ensure their diets contain plenty of folate. Excellent sources of this nutrient include beans, lentils and green leafy vegetables.

References:

1. Zhang SM, et al. Alcohol consumption and breast cancer risk in the Women’s Health Study Am J Epidemiol, 2007; 165(6): 667-76

2. Dumitrescu RG, et al. The etiology of alcohol-induced breast cancer. Alcohol. 2005 Apr;35(3):213-25.

3. Baglietto L, et al. Does dietary folate intake modify effect of alcohol consumption on breast cancer risk? Prospective cohort study. BMJ. 2005 Oct 8;331(7520):807

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