Moderate Alcohol Consumption - Cancer Benefits

Alcohol consumption lowers the risk of several types of cancer

Many observational epidemiologic studies have found an inverse association between alcohol consumption and hematological cancers (such as lymphoma and leukemia). This study, based on the Million Women's Study in the UK, is large enough to permit an evaluation of associations with various types of such cancers. Further, it takes into account newer coding systems for morphology so that diseases associated with the lymphatic system can be separated from those of the myeloid system.

The key findings are that alcohol consumption appears to lower the risk of several types of lymphoma and plasma cell neoplasms, but has little effect on the risk of myeloid tumours such as acute myeloid leukemia.

Moderate alcohol intake is associated with a lower risk of kidney cancer

A majority of previous epidemiologic studies have shown that moderate drinking is associated with a lower risk of kidney cancer, which may affect about 1% of the general population. In published prospective cohort studies, the risk for such cancer among moderate drinkers is usually about 25% less than the risk seen among non-drinkers.

This well-done meta-analysis supports these findings: for the more-reliable prospective cohort studies (rather than case-control studies) the current study finds a 29% lower risk for subjects in the highest category of alcohol consumption in comparison with subjects in the lowest alcohol category. The findings suggest similar effects among men and women, and for all types of alcohol beverages. The effects are seen at a level of about one drink/day, with little further reduction in risk for greater alcohol consumption.

Alcohol consumption and risk of colon cancer

A study based on more than 87,000 women and 47,000 men in the Nurses' Health Study and the Health Professionals Follow-up Study, looks at whether there is a link between colon cancer and alcohol, and if so at what level of consumption, and the importance of a family history of the disease. A total of 1,801 cases of colon cancer were diagnosed during follow-up from 1980 onwards.

The authors’results found that subjects with a family history, whose average alcohol intake was 30 or more grams per day (about 2 ½ typical drinks by US standards or 4 UK units) had an increase in their risk of colon cancer. Those at greatest risk also ate the most red meat, smoked the most, and had the lowest intake of folate (suggesting they ate fewer green vegetables and cereals. Hence, these people have the most unhealthy lifestyles in general of the populations studied. There was not a significant association between alcohol consumption and colon cancer among subjects without a positive family history in this study.

Forum reviewers were concerned that the pattern of drinking (regularly or binge drinking) was not assessed, and that there was not a consistent increase in risk of cancer with greater alcohol intake found. Further, adequate folate intake was found to lower risk, with the highest risk for subjects with a positive family history of colon cancer, low levels of folate, and in the highest category of alcohol consumption, indicating the importance of other lifestyle facts such as a healthy diet.

The present study provides some support for an association between higher levels of alcohol intake and the risk of colon cancer among subjects with a positive family history of such cancer. It should be noted that there have been changes in the guidelines for screening for colon cancer (by endoscopy, with removal of pre-malignant tumours) and other preventive measures for people with a positive family history of colon cancer, making it hard to draw conclusions on data for colon cancer that is 30 years old. The new recommendation for screening frequency and age at initiation of screening are so different now. At least some of these cases would probably have been prevented if managed according to current guidelines. Such measures could modify the effects of all risk factors for colon cancer in future analyses. 

Light drinking = significant decrease in cancer risk 

A paper from the National Institutes of Health in the United States has evaluated the separate and combined effects of the frequency of alcohol consumption and the average quantity of alcohol drunk per occasion and how that relates to mortality risk from individual cancers as well as all cancers. The analysis is based on repeated administrations of the National Health Interview Survey in the US, assessing more than 300,000 subjects who suffered over 8,000 deaths from cancer. The research reports on total cancer deaths and deaths from lung, colorectal, prostate, and breast cancers.

The overall message of this analysis is that light to moderate alcohol intake does not appear to increase the risk of all-site cancer (and light drinking was shown in this study to be associated with a significant decrease in risk). Similarly, light to moderate consumption was not associated with site-specific cancers of the lung, colorectum, breast, or prostate.

As quantity consumed increased from 1 drink on drinking days to 3 or more drinks on drinking days (US drinks are 14g), risk of all-site cancer mortality increased by 22% among all participants. For total alcohol consumption (frequency x quantity), the data indicate a significant reduction in the risk of all-site cancers (RR=0.87, CI 0.80-0.94). Moderate drinking consistently shows no effect in the analysis, and only heavier drinking was associated with an increase in all-site cancer risk. For site-specific cancers, an increase in risk of lung cancer was seen for heavier drinkers, with a tendency for less cancer among light drinkers. There was no evidence of an effect of total alcohol consumption on colorectal, prostate, or breast cancer.

The authors excluded non-drinkers in a second analysis in which they used categories of usual daily quantity and of frequency of consumption in an attempt to investigate their separate effects. For all-site cancer and for lung cancer, these results again show an increase in risk only for drinkers reporting greater amounts of alcohol. The data also show an increase in cancer risk from more frequent drinking among women but not among men. For colorectal, prostate, and breast cancer, there is no clear pattern of an increase in risk from quantity of alcohol consumed. For frequency of drinking, again there is a suggestion of an increase in mortality risk with more frequent drinking, although the trends are not statistically significant.

Heavier drinking (three drinks or more per occasion) is known to be associated with a large number of adverse health effects, including certain cancers, as was shown in this study.

Drinking wine lowers risk of Barrett's esophagus, precursor to nation's fastest growing cancer

Drinking one glass of wine a day may lower the risk of Barrett's Esophagus by 56 percent, according to a study by the Kaiser Permanente Division of Research in the March, 2009 issue of Gastroenterology. Barrett's Esophagus is a precursor to esophageal cancer, the nation's fastest growing cancer with an incidence rate that's jumped 500 percent in the last 30 years.

Barrett's Esophagus affects 5 percent of the population and occurs when heartburn or acid reflux permanently damages the esophageal lining. People with Barrett's Esophagus have a 30- to 40-fold higher risk of developing esophageal adenocarcinoma (a type of esophageal cancer) because the Barrett's Esophagus cells can grow into cancer cells.

Because there are no symptoms or warning signs of Barrett's Esophagus, people discover they have Barrett's Esophagus when an endoscopy for anemia, heartburn or a bleeding ulcer reveals esophageal cells that were damaged, then changed form during the healing process. Currently nothing can be done to treat Barrett's Esophagus; it can only be monitored.

This is the first and largest population-based study to examine the connection between alcohol consumption and risk of Barrett's Esophagus. Funded in part by the National Institutes of Health, the Kaiser Permanente study looked at 953 men and women in Northern California between 2002 and 2005 and found that people who drank one or more glasses of red or white wine a day had less than half the risk (or 56 percent reduced risk) of Barrett's Esophagus. There was no reduction of Barrett's Esophagus risk among people who drank beer or liquor.

"The rate of esophageal adenocarcinoma in this country is skyrocketing yet very little is known about its precursor, Barrett's Esophagus. We are trying to figure out how to prevent changes that may lead to esophageal cancer." said Douglas A. Corley, MD, a Kaiser Permanente gastroenterologist and the study's principal investigator.

The study findings are echoed by two other studies published in the same issue of the Gastroenterology journal: Australian researchers found that people who drank wine were at a lower risk of esophageal adenocarcinoma, and Irish researchers found that people who drank wine were at a lower risk for esophagitis, an irritation of the esophagus that follows chronic heartburn and often precedes Barrett's Esophagus and cancer.

Researchers are not certain why wine reduces the risk of Barrett's Esophagus and esophageal cancer. One theory is that the wine's antioxidants neutralize the oxidative damage caused by gastroesophageal reflux disease, a risk factor for Barrett's Esophagus. Another theory is that wine drinkers typically consume food with their wine as opposed to drinking straight liquor without food, thereby reducing the potentially damaging effect of alcohol on esophageal tissue, said Ai Kubo, MD, an epidemiologist at Kaiser Permanente and lead author on the study. "But we cannot preclude the possibility that wine drinking is a proxy for other 'health-seeking' behavior," Kubo added.

This study is part of larger, case-controlled Kaiser Permanente study led by Dr. Corley that looked at abdominal obesity and consumption of dietary antioxidants, fruits and vegetables in connection with Barrett's Esophagus. It found that people can reduce their risk of Barrett's Esophagus by eating eight servings of fruits and vegetables a day and maintaining a normal body weight.

"My advice to people trying to prevent Barrett's Esophagus is: keep a normal body weight and follow a diet high in antioxidants and high in fruits and vegetables," Corley said. "We already knew that red wine was good for the heart, so perhaps here is another added benefit of a healthy lifestyle and a single glass of wine a day."

Researchers noted, though, that the protective effect of wine in terms of preventing Barrett's Esophagus was greatest with just one or two glasses a day. The protective effect of wine did not increase with higher consumption.

"It's not actually clear that treating the acid reflux will necessarily prevent getting someone from getting Barrett's Esophagus," said Dr. Corley. "The best way to prevent reflux is to maintain a normal weight."

Moderate red wine drinking may help cut women's breast cancer risk

Drinking red wine in moderation may reduce one of the risk factors for breast cancer, providing a natural weapon to combat a major cause of death among U.S. women, new research from Cedars-Sinai Medical Center shows.

The study, published online in the Journal of Women's Health, challenges the widely-held belief that all types of alcohol consumption heighten the risk of developing breast cancer. Doctors long have determined that alcohol increases the body's estrogen levels, fostering the growth of cancer cells.

But the Cedars-Sinai study found that chemicals in the skins and seeds of red grapes slightly lowered estrogen levels while elevating testosterone among premenopausal women who drank eight ounces of red wine nightly for about a month.

White wine lacked the same effect.

Researchers called their findings encouraging, saying women who occasionally drink alcohol might want to reassess their choices.

"If you were to have a glass of wine with dinner, you may want to consider a glass of red," said Chrisandra Shufelt, MD, assistant director of the Women's Heart Center at the Cedars-Sinai Heart Institute and one of the study's co-authors. "Switching may shift your risk."

Shufelt noted that breast cancer is the leading type of women's cancer in the U.S., accounting for more than 230,000 new cases last year, or 30 percent of all female cancer diagnoses. An estimated 39,000 women died from the disease in 2011, according to the American Cancer Society.

In the Cedars-Sinai study, 36 women were randomized to drink either Cabernet Sauvignon or Chardonnay daily for almost a month, then switched to the other type of wine. Blood was collected twice each month to measure hormone levels.

Researchers sought to determine whether red wine mimics the effects of aromatase inhibitors, which play a key role in managing estrogen levels. Aromatase inhibitors are currently used to treat breast cancer.

Investigators said the change in hormone patterns suggested that red wine may stem the growth of cancer cells, as has been shown in test tube studies.

Co-author Glenn D. Braunstein, MD, said the results do not mean that white wine increases the risk of breast cancer but that grapes used in those varieties may lack the same protective elements found in reds.

"There are chemicals in red grape skin and red grape seeds that are not found in white grapes that may decrease breast cancer risk," said Braunstein, vice president for Clinical Innovation and the James R. Klinenberg, MD, Chair in Medicine.