This graph looks pretty innocuous doesn’t it? Innocuous it may be, but it helps explain the key finding from our Continuous Update Project, on the link between diet, weight, physical activity and liver cancer that found three alcoholic drinks a day can cause liver cancer. It’s a graph pulled from our review of the science literature (or SLR) put together in 2014 and available to read on our website here. What this graph shows is the level of daily alcohol consumption beyond which the risk of liver cancer increases disproportionately. Below 45 grams of alcohol a day, (that’s up to three drinks or six units) the slope of the line is fairly flat. But at around 45 grams of alcohol per day the evidence shows the increase in liver cancer risk becomes statistically significant. This means that it is unlikely to be a chance finding.
A new insight into alcohol and cancer
Since 2007 we have known that there is a link between alcohol and liver cancer. What is important about this latest review is that it has identified a threshold. This is important because it it advances what we know about the level of drinking that increases liver cancer risk. It adds to our knowledge of the links between diet, nutrition physical activity and cancer, which is the aim of our Continuous Update Project (CUP)
Exposure and risk
Studies investigating how dietary and nutritional factors increase cancer risk produce data in various ways, depending on what is most useful. Data can show an averaged risk level across the range of intake, say of alcoholic drinks, which will average all the data out to produce a uniform risk estimate for a given unit of the exposure (for example, per 10 grams of alcohol consumed, or per 5 BMI units). Our research found that this type of analysis showed there was a 4% increased risk per 10 grams of alcohol consumed. But when there is reason to believe, from the evidence, that this averaging might be hiding something important, we can perform another analysis to uncover fluctuations in risk that come with different levels of consumption. For example, sometimes no effect in terms of cancer risk is seen up to a certain level of intake, but there might be a point, or threshold, at which increasing (or decreasing) intake starts to affect cancer risk. Put another way, our analysis found that:
- At an intake below 45 grams a day there was no clear and consistent increase in risk of liver cancer
- At about 45 grams of alcohol per day liver cancer risk increases by 6%;
- Between 45 grams and 75 grams of alcohol per day the risk increase is steeper, going up to 23% at 75 grams per day (See the SLR, table 42 here).
The bottom line in terms of health is this: alcohol consumption is associated with a range of health problems. If you drink at all, we recommend limiting your alcoholic intake to one drink for women and two drinks for men. You can also check our Cancer Prevention Recommendations for more information.