A new study from England finds that only moderate alcohol consumption benefits your heart. The study was released on March 22, 2017 in Great Britain. 1.937 million people (51% women, 49% men) had participated in this investigation over 6 years. The lead author, Dr. Steven Bell is a genetic epidemiologist. He said that this study was done to clear up some of the confusion from previous studies. He wondered why the control group without alcohol exposure had more cardiac problems than the moderate group. It did make sense though, that the high alcohol group had worse cardiac problems.
But he and researchers from Cambridge University and University College London did this study to get more detail. They wanted to know why the current non-drinking group used as a control was not looked at more carefully. It consisted of a mix of lifelong abstainers; people who drank formerly, but then gave it up. And the other group was those who drink on an occasional basis.
With this in mind the researchers designed their study. They also used also larger numbers to increase the reliability of the study.
Details of English study
The data comes from the Clinical Practice Research Datalink providing anonymous patient records from general practices in England. The patients upon entry into the study had to be older than 30 years, but have no evidence of cardiovascular disease. A total of 1,937,360 patients qualified to be part of the study.
Based on patients’ records and patients recollections people, researchers looked at 5 classes of drinkers:
- Non-drinkers (14.3%)
- Former or ex-drinkers (stopped drinking at one point, 3.7%)
- Occasional drinkers (drinking rarely, 11.9%)
- Moderate drinkers (drinking within sensible limits, 61.7%)
- Heavy drinkers (hazardous alcohol use, 8.4%)
The end point of the study researchers concentrated on the frequency of cardiovascular diseases like angina, heart attack, sudden cardiac death, stroke, peripheral arterial disease, abdominal aortic aneurysm and others. I only listed 6 of the 12 cardiovascular diagnoses as otherwise it would get too technical.
More information: Most study participants were non-smokers, their BMI was within normal limits, and they also did not have diabetes.
Findings of the study
There were significant differences among subclasses of alcohol consumption and the development of cardiovascular diseases over 6 years.
- The findings were in line with a number of previous similar studies that showed a U-type dose response curve between developing cardiovascular diseases and alcohol consumption. The group of non-drinkers (where former and occasional drinkers were removed) often had a 20% to 56% increased risk of developing cardiovascular disease, while moderate drinkers had no added risk.
- On the other hand the heavy drinkers were at risk of developing cardiac arrest (50% increased risk) or heart failure (22% increased risk). A death from a sudden heart attack occurred in heavy drinkers with a risk of 21% increased risk. A former drinker had a 40% increased risk for this, but a non-drinker a risk of 56% increased risk!
- A non-drinker had a 32% increased risk of getting a regular heart attack, a former drinker had a 31% increased risk, an occasional drinker 14%, a moderate drinker no added risk, and a heavy drinker had a 12% reduced risk! This seemed to show that drinking alcohol keeps the coronary arteries open and clean. I have had pathology demonstrations with Professor Dr. Adalbert Bohle at Tübingen University during my medical training in 1969. At that time he pointed out how clear and wide open the coronary arteries were in chronic alcoholics. It was not heart disease that killed those patients; they had died from end stage liver cirrhosis, and we saw pathological slides of that.
- Heavy drinkers get more ischemic strokes (33% increased risk) and more intracerebral hemorrhages (37% increased risk).
- Obstruction of blood vessels in the lower legs (peripheral arterial disease) is common with heavy drinkers (35% increased risk) and even former drinkers (32% increased risk). Non-drinkers have a 22% increased risk while moderate drinkers have a 0% risk (no increased risk).
- There was no association between heavy drinking and aortic aneurysm. On the other hand, non-drinkers (32% increased risk) and former drinkers (23% increased risk) showed an increased risk of aortic aneurysm formation.
Other effects of alcohol consumption
The study above did not take into consideration that alcohol consumption has many other consequences beside cardiovascular effects. One for instance is the effect on the brain and the increase of serious car accidents. Another effect is the causation of cancer.
The American Cancer Society clearly states that alcohol consumption has been causatively associated with the following cancers.
- Cancer of the mouth
- Cancer of the pharynx (throat)
- Cancer of the larynx (voice box)
- Cancer of the esophagus
- Cancer of the liver
- Cancer of the breast
- Cancer of the colon
- Alcohol also plays a role with cancer of the pancreas
Many studies have shown a dose-response curve between alcohol consumed and the development of these cancers. In other words there is never a safe low dose, below which no cancer would be caused over time.
These authors conducted a metaanalysis of 16 prospective cohort studies including 6,300 patients. It showed that alcohol caused cancer of the colon and rectum. High intake of alcohol showed a 50% increased risk of causing colon cancer. With regard to rectal cancer the risk was 63% higher. In both cases the highest alcohol intake was compared to the lowest category of alcohol intake.
These authors concluded their discussion by pointing out that 6% of the worldwide cancer deaths are attributed to alcohol intake. They also stated that colorectal cancer risk increased by 50% in the heaviest alcohol users. Among the group of heavy drinkers the cancer death rate would likely be 9%. There would a reduction of mortality from cardiovascular disease by one third in middle and old age. The end result would be 6% mortality again; essentially there is no change.
No matter how you try to solve this equation, there is a risk of cancer deaths from exposure to alcohol. There is also a risk that heavy drinking can cause significant cardiovascular diseases mentioned.
Everything we do in life has consequences. With regard to drinking you know that accidents are more common in drinkers; with prolonged exposure to higher alcohol consumption you can get dementia. Moderate amounts appear to have significant protection from heart disease, but the risk for several cancers is not negligible. This point was not mentioned in the study I discussed in the beginning of my blog. In the latter part I included some data about cancer risks from alcohol consumption.
The paradox remains that non-consumption of alcohol is associated with a significant cardiovascular risk because of a U-shape dose response curve. Moderate alcohol use is associated with the lowest cardiovascular risk. The question is whether we can balance moderate drinking with staying in the low cancer risk area. The recommendation of 1 glass of wine for women and 2 glasses of wine for men has been confirmed by the above study. This is considered a healthy preventative dose with respect to cardiovascular risk. It is the official recommendation for cardiovascular disease prevention. The cancer literature clearly states that there is a small cancer risk from moderate alcohol intake. This is particularly true for the 8 cancers discussed.
Dr James Nicholls, the director of research and policy development at Alcohol Research UK had this to say. He pointed to the fact that there are other ways to prevent cardiovascular disease. For those who do not drink at present it would not make sense to take up drinking. You can strengthen your heart by starting a Mediterranean diet and starting to exercise regularly. The beneficial substance for your heart in red wine is known as resveratrol that can be taken as a supplement. Resveratrol has no side effects and does not have the cancer risk of an alcoholic drink. Dr. Nicholls added, “If you drink within the existing guidelines it is unlikely that alcohol will either lengthen or shorten your life.” It is really up to every individual to balance the wine glass with personal health!