13. Alcohol

An American study that followed the diet and lifestyles of more than 200,000 women for almost 14 years found that postmenopausal women who drank one drink per day or more had an almost 30 per cent increase in breast cancer rates compared to women who did not drink at all. Alcohol use is the second leading cause of cancer, right behind tobacco use. While a moderate or low consumption of alcohol can be healthy and lead to a reduced risk of heart disease, excessive drinking is known to cause heart failure, stroke, and sudden death. In 2007, experts working for the World Health Organization’s International Agency for Research on Cancer looked at the scientific evidence regarding cancer and alcohol use from 27 different studies. They found sufficient evidence to state that excessive alcohol use is the main cause of mouth, oesophagus, liver, colon, mouth, rectum and female breast cancers.