Thursday March 26, 2015 (foodconsumer.org) -- On March 25, World Cancer Research Fund International (WCRF) reported on its website that drinking alcoholic beverages can induce liver cancer.  That is, drinking three glasses (750 ml) of wine per day or an amount equivalent to 45 grams of alcohol increases risk of liver cancer.  To be exact, an additional 10 grams of alcohol increases the risk by 4%.

The new analysis based on data from 34 studies of 8,200,000 men and women of whom 25,000 were diagnosed with liver cancer, did not find intake of less than 45 grams of alcohol associated with increased risk of liver cancer.

Alcoholic beverage consumption has been recognized as a human carcinogen by the U.S. National Toxicology Program for many years now.  This means that drinking alcohol can raise the risk of cancers including liver cancer that is the second most common cause of death worldwide.

Physicians in the U.S. recommend men and women should refrain from drinking alcoholic beverages such as wine, beer and liquors.  Men who cannot stop drinking should drink no more than 2 glasses per day whereas women who cannot quit drinking should drink no more than 1 glass per day.  This recommendation is very vague in terms of the maximum intake of alcohol.   Doctors do suggest that those who do not drink should not start drinking any alcohol.   WCRF also recommends the same.

Drinkaware in the UK suggests that in order to reduce the risk of liver cancer induced by drinking alcohol, women should drink no more than one glass or 175 ml  of an alcoholic beverage with 13% alcohol (22.75 grams of alcohol) whereas men should not drink an amount of an alcoholic beverage equivalent to 750 ml of beer.  Beer has about 4 % alcohol (37.5 grams of alcohol).

Drinking alcohol has been linked to other types of cancer.  For example, drinking alcohol has been associated with increased risk of breast cancer.  One metabolite of alcohol called acetaldehyde is highly reactive and can react with other biomolecules in cells causing injury to DNA and increasing cancer risk.  Acetaldehyde dehydrogenase converts acetaldehyde and CoA into acetyl-CoA, which is not toxic.  Therefore, men and women who lack this enzyme should avoid drinking any alcohol.   People do not have sufficient enzymes if they become red-faced after drinking a few grams of alcohol.  Nearly half Asians lack acetaldehyde dehydrogenase.

The new study also found strong evidence indicating that being overweight or obese is a risk factor for liver cancer.    It is known that high fat diets can induce obesity and high fat diets are damaging to the liver and promote the development of fatty liver or steatosis, which may explain why being overweight or obese is a cause for liver cancer.  Being overweight or obese has also been associated with other 9 cancers.  

Another risk factor for liver cancer can be foods contaminated by aflatoxins which are produced by a fungus on foods inappropriately stored.   Interestingly, WCRF does not list hepatitis B virus as a cause for liver cancer on its website.   Hepatitis B virus is highly toxic and should be considered at least as dangerous as aflatoxins.   Moldy corn, peanuts, and grains should be avoided.

The WCRF study also revealed that drinking coffee can lower the risk of liver cancer.  One cup of coffee per day may cut the risk of liver cancer by 14%.  But the association may not be causal, that is, drinking coffee may not definitely lower the risk.

Many countries have their own recommendations on alcohol consumption. Alcohol is  a toxic substance.  In the United States, alcohol consumption is the fourth leading preventable cause of deaths. Each year, 88,000 deaths in the US are alcohol-related. (David Liu)