Researchers have formulated many hypotheses about how alcohol can increase cancer risk, such as: By metabolizing (decomposing) ethanol in alcoholic beverages to acetaldehyde, which is a toxic chemical and a probable human carcinogen; Acetaldehyde can damage both DNA (the genetic material that makes up genes) and proteins. By generating reactive oxygen species (chemically reactive oxygen-containing molecules), which can damage DNA, proteins, and lipids (fats) in the body through a process called oxidation By impairing the body's ability to break down and absorb a variety of nutrients that may be associated with the risk of cancer, including vitamin A; nutrients in the vitamin B complex, such as folate; vitamin C; vitamin D; Vitamin E; and carotenoids By increasing the levels of estrogen in the blood, which is a sex hormone