A new study confirms a strong connection between long-term, heavy alcohol consumption and an increased risk of colorectal cancer, especially in the rectum. Researchers found that individuals who consistently drink more than 14 alcoholic beverages per week – roughly two or more drinks daily – face a 25% higher overall risk of developing colorectal cancer and a 95% higher risk of rectal cancer compared to moderate drinkers.
The Lifetime Impact of Alcohol Consumption
The findings, published in the journal Cancer, reinforce the understanding that alcohol’s harmful effects accumulate over time. While heavy drinkers who quit or drastically reduce their intake can lower their risk, the study underscores that consistent heavy drinking is a meaningful and preventable cancer risk factor.
The research analyzed data from over 88,000 adults over a 20-year period, categorizing participants into light (under 7 drinks per week for women, under 14 for men), moderate (7–14/14–21 drinks), and heavy drinkers (over 14/21 drinks). Almost 1,700 participants developed colorectal cancer during the study, with heavy drinkers disproportionately represented.
How Alcohol Contributes to Cancer Development
The body breaks down alcohol into acetaldehyde, a toxic chemical linked to DNA and protein damage, increasing cancer risk. The National Cancer Institute also notes that excessive alcohol intake may impair the absorption of vital nutrients – including vitamins A, B, C, D, and E, as well as carotenoids – that could otherwise help ward off cancer.
Quitting or Cutting Back Can Make a Difference
The study provides a clear takeaway: quitting or significantly reducing alcohol consumption can lower cancer risk to levels comparable to light drinkers. Former heavy drinkers saw their odds of developing noncancerous colorectal tumors, which can become cancerous, reduced by 42% compared to current light drinkers.
The Importance of Early Detection and Screening
Colorectal cancer is the second leading cause of cancer death in the United States. Early detection through screening dramatically improves survival rates. Key symptoms include changes in bowel habits, rectal bleeding, persistent abdominal discomfort, and unexplained weight loss. The U.S. Preventive Services Task Force recommends that adults at average risk begin screening at age 45.
Rising Rates Among Younger Adults
Colorectal cancer rates are decreasing in older adults but increasing in those under 50, although this population generally drinks less alcohol than in the past. Researchers acknowledge that alcohol is not the only factor driving this trend, and further investigation is needed to identify other contributing causes.
Ultimately, the study reinforces that minimizing alcohol intake is beneficial, especially over the long term. Staying up-to-date with colorectal cancer screening remains the most effective way to prevent cancer and detect problems early.
Editorial Sources:
O’Connell C et al. Association of Alcohol Intake Over the Lifetime with Colorectal Adenoma and Colorectal Cancer Risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Cancer. January 26, 2026.
Alcohol and Cancer Risk. National Cancer Institute. May 2, 2025.
