There is strong evidence that alcohol causes seven types of cancer and probably others, a review has concluded.

A study of existing research found strong evidence of a direct, harmful effect of drinking, even though scientists are unsure of the exact biological reasons why alcohol causes cancer.

Writing in the journal Addiction, Jennie Connor, from the University of Otago in New Zealand, said alcohol is estimated to have caused about half a million deaths from cancer in 2012 alone – 5.8 per cent of cancer deaths worldwide. The highest risks are from heavy drinking, but even people who drink at low levels are at risk.

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Her review linked alcohol to cancer of the mouth and throat, larynx, oesophagus, liver, colon, bowel and breast.

She said: “There is strong evidence that alcohol causes cancer at seven sites, and probably others. Confirmation of specific biological mechanisms by which alcohol increases the incidence of each type of cancer is not required to infer that alcohol is a cause.”

She said that based on current evidence, there is no safe level of drinking with respect to cancer though the risks are reduced for some cancers when people stop drinking.She added that the supposed health benefits of drinking – such as red wine being good for the heart – were “seen increasingly as disingenuous or irrelevant in comparison to the increase in risk of a range of cancers”.

In January, the UK's chief medical officers said no level of regular drinking is without risks to health.

Publishing a raft of recommendations, they said men should consume no more than 14 units of alcohol per week, down from the previous 21 units, bringing them into line with the recommendation for women.

Modelling for the study showed that, compared with non-drinkers, women who regularly drink two units a day have a 16 per cent increased risk of developing breast cancer and dying from it. Those who regularly consume five units a day have a 40 per cent increased risk.

For every 1,000 women who do not drink, 109 will develop breast cancer. This rises to 126 women for those who drink 14 units or less per week, and 153 women for those who drink 14 to 35 units a week.

Scientists are still researching how alcohol can lead to cancer. One theory is that alcohol damages DNA.

Shape Created with Sketch. 13 ways to help prevent cancer Show all 13 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. 13 ways to help prevent cancer 1/13 Stopping smoking. This notoriously difficult habit to break sees tar build-up in the lungs and DNA alteration and causes 15,558 cancer deaths a year 2/13 Avoiding the sun, and the melanoma that comes with overexposure to harmful UV rays, could help conscientious shade-lovers dodge being one of the 7,220 people who die from it 3/13 A diet that is low in red meat can help to prevent bowel cancer, according to the research - with 30 grams a day recommended for men, and 25 a day recommended for women 4/13 Foods high in fibre, meanwhile, can further make for healthier bowels. Processed foods in developed countries appear to be causing higher rates of colon cancer than diets in continents such as Africa, which have high bean and pulse intakes 5/13 Two servings of fruit and three servings of vegetables a day were given as the magic number for good diet in the research. Overall, diet causes only slightly fewer cancer deaths than sun exposure in Australia, at 7,000 a year 6/13 Obesity and being overweight, linked to poor diet and lack of exercise, causes 3,917 deaths by cancer a year on its own Getty 7/13 Dying of a cancer caused by infection also comes in highly, linked to 3,421 cancer deaths a year. Infections such as human papilloma virus - which can cause cervical cancer in women - and hepatitis - can be prevented by vaccinations and having regular check-ups 8/13 Cutting back on drinks could reduce the risk of cancers caused by alcohol - such as liver cancer, bowel cancer, breast cancer and mouth cancer - that are leading to 3,208 deaths a year 2014 Getty Images 9/13 Sitting around and not getting the heart pumping - less than one hour's exercise a day - is directly leading to about 1,800 people having lower immune functions and higher hormone levels, among other factors, that cause cancers 2011 Getty Images 10/13 Hormone replacement therapy, which is used to relieve symptoms of the menopause in women, caused 539 deaths from (mainly breast) cancer in Australia last year. It did, however, prevent 52 cases of colorectal cancers 2003 Getty Images 11/13 Insufficient breastfeeding, bizarrely, makes the top 10. Breastfeeding for 12 months could prevent 235 cancer cases a year, said the research AFP/Getty Images 12/13 Oral contraceptives, like the Pill, caused about 105 breast cancers and 52 cervical cancers - but it also prevented about 1,440 ovarian and uterine (womb) cases of cancer last year 2006 Getty Images 13/13 Taking aspirin also prevented 232 cases in the Queensland research of colorectal and oesophagal cancers - but as it can also cause strokes, is not yet recommended as a formal treatment against the risk of cancer 1/13 Stopping smoking. This notoriously difficult habit to break sees tar build-up in the lungs and DNA alteration and causes 15,558 cancer deaths a year 2/13 Avoiding the sun, and the melanoma that comes with overexposure to harmful UV rays, could help conscientious shade-lovers dodge being one of the 7,220 people who die from it 3/13 A diet that is low in red meat can help to prevent bowel cancer, according to the research - with 30 grams a day recommended for men, and 25 a day recommended for women 4/13 Foods high in fibre, meanwhile, can further make for healthier bowels. Processed foods in developed countries appear to be causing higher rates of colon cancer than diets in continents such as Africa, which have high bean and pulse intakes 5/13 Two servings of fruit and three servings of vegetables a day were given as the magic number for good diet in the research. Overall, diet causes only slightly fewer cancer deaths than sun exposure in Australia, at 7,000 a year 6/13 Obesity and being overweight, linked to poor diet and lack of exercise, causes 3,917 deaths by cancer a year on its own Getty 7/13 Dying of a cancer caused by infection also comes in highly, linked to 3,421 cancer deaths a year. Infections such as human papilloma virus - which can cause cervical cancer in women - and hepatitis - can be prevented by vaccinations and having regular check-ups 8/13 Cutting back on drinks could reduce the risk of cancers caused by alcohol - such as liver cancer, bowel cancer, breast cancer and mouth cancer - that are leading to 3,208 deaths a year 2014 Getty Images 9/13 Sitting around and not getting the heart pumping - less than one hour's exercise a day - is directly leading to about 1,800 people having lower immune functions and higher hormone levels, among other factors, that cause cancers 2011 Getty Images 10/13 Hormone replacement therapy, which is used to relieve symptoms of the menopause in women, caused 539 deaths from (mainly breast) cancer in Australia last year. It did, however, prevent 52 cases of colorectal cancers 2003 Getty Images 11/13 Insufficient breastfeeding, bizarrely, makes the top 10. Breastfeeding for 12 months could prevent 235 cancer cases a year, said the research AFP/Getty Images 12/13 Oral contraceptives, like the Pill, caused about 105 breast cancers and 52 cervical cancers - but it also prevented about 1,440 ovarian and uterine (womb) cases of cancer last year 2006 Getty Images 13/13 Taking aspirin also prevented 232 cases in the Queensland research of colorectal and oesophagal cancers - but as it can also cause strokes, is not yet recommended as a formal treatment against the risk of cancer

Susannah Brown, science programme manager for the World Cancer Research Fund (WCRF), said of the new work: “Many people believe that alcohol consumption is only linked to liver cancer, but this review confirms the findings of our Continuous Update Project that alcohol is strongly linked to an increased risk of a number of different cancers, including two of the most common – bowel and breast cancer.

“Among other evidence, we see the risk increasing as the amount of alcohol consumed increases, and we agree that there is solid evidence to conclude that alcohol consumption directly causes cancer. For cancer prevention, we have long recommended that people should not drink alcohol at all, but we understand that this can be easier said than done.”

The WCRF has previously said that drinking three alcoholic drinks or more per day increases the risk of stomach cancer

It also found strong evidence for a link with other cancers, including mouth and throat, liver, bowel and breast.

PA