About the benefits and harms of alcohol

Karina Nazarethyan, N+1
(for numerous references to sources, see the original article – VM).

"Alcohol in small doses is useful in any quantities" – doctors like to remember this joke, explaining why they prefer not to tell patients about the possible benefits of moderate drinking. No one particularly doubts that excessive alcohol consumption is harmful to health. But about moderate doses, battles have been going on for years.

First you need to understand what "moderate use" is. The fact is that the norms vary greatly in different countries. The differences begin with what is considered one "serving" (or "drink"): in the UK, for example, it is 8 grams of alcohol, and in Japan – almost 20. In the USA, a serving is considered to be 14 grams of alcohol: this is the equivalent of 350 milliliters (about a can) of beer, 150 milliliters (about a glass) of wine or 45 milliliters (about a shot glass) of vodka.

Accordingly, the ideas about when to stop are also different everywhere. In the UK, it is believed that 3-4 servings (i.e. 24-32 grams of alcohol) per day for men "do not entail noticeable harm to health"; for women it is 2-3 servings (16-24 grams). In Japan, men are officially recommended to drink no more than two servings of sake per day (39.5 grams of alcohol); there are no guidelines for women. Finally, in the USA, men are advised to drink no more than two servings a day (28 grams), and women – no more than one (14 grams). By the way, the norms for women are lower not only because they usually weigh less, but also because of sex differences in alcohol metabolism.

Different ideas about moderation lead to some confusion in conversations about the benefits and harms of "moderate use", but still, usually in such cases we are talking about 10-30 grams of alcohol per day. And, apparently, alcohol of any kind: attempts to find out which drinks have a better effect on health and which ones are worse (for example, whether red wine really has advantages) have not yielded convincing results.

It should be noted that there is a serious problem with the science of the benefits and harms of alcohol: long-term randomized studies (that is, those where people would be randomly divided into groups and given alcohol to some for a long time, and not to others) there was no discussion on this topic. All existing works can be divided into two types: short-term, studying the effect of alcohol on specific physiological parameters, and long-term observational, which usually compares the health of those who drink moderately and those who do not drink at all. But there are problems with both types of studies: short-term studies can only reveal short-term effects, and long-term observational studies lack randomization, that is, random distribution. The group of those who do not drink at all may include, for example, people with alcohol addiction in the past or people with serious illnesses, including mental ones – and these factors can greatly affect their life expectancy and, accordingly, the results.

Benefit or harm

However, in the absence of other scientific data, we have to rely on what we have. Numerous studies in different countries have shown that people who drink alcohol moderately have slightly lower mortality rates than teetotallers. A meta-analysis of 34 papers on this topic revealed that the lowest mortality rate was among those men and women who consumed an average of 6 grams of alcohol (that is, about half of an American serving) per day.

Such studies have strict critics: the authors of several review analyses claim that many works on this topic contain errors and, for example, if people with alcohol dependence in the past are excluded from the group of "teetotallers", then the apparent healing effect of using small doses practically disappears.

In any case, it is important not to fall into the temptation to see persistent cause-and-effect relationships where, in fact, there is only correlation. Mortality rates, even in a large sample, can be influenced by hundreds of different factors that are very difficult to take into account in the study. The fact that moderate drinkers live longer does not necessarily mean that it is alcohol that lengthens their lives. Although there are grounds for such an assumption.

Benefit

A large number of scientific papers have shown the connection of moderate alcohol consumption with a reduced risk of developing a variety of problems of the cardiovascular system. Among them are coronary heart disease, heart failure, stroke, peripheral artery disease. Alcohol is associated with lower mortality in people with high blood pressure.

Some studies show that moderate drinkers – both women and men – have a lower risk of developing cholelithiasis compared to teetotallers.

There is quite convincing evidence that moderate alcohol consumption is associated with a reduced risk of developing diabetes.

However, all these positive effects disappear with an increase in the amount of alcohol – usually after 3-4 servings per day in men and 2-3 in women. That is, with more intensive alcohol consumption, the association with positive health indicators is lost and a negative correlation begins to be noted: the more you drink, the worse your health is. Graphs in many studies on this topic resemble the letter "J": with moderate use, morbidity / mortality goes down slightly compared to the "zero" level of use, and then with an increase in dose - linearly up.

Harm

But with the possible benefits of moderate drinking, of course, everything is not so simple. Even light alcohol consumption is associated with an increased risk of developing certain types of cancer. This is especially evident with breast cancer in women: according to some data, up to 8 percent of breast cancer cases may be associated with the use of alcoholic beverages by a woman. Alcohol is associated with an increased risk of developing head and neck tumors (especially in combination with smoking), hepatic cell carcinoma in people with hepatitis C, colorectal cancer (although the data here are contradictory).

At the same time, pancreatic cancer is associated only with heavy drinking (for example, 57 servings per week for men), and the same can be said about pancreatitis: apparently, its increased risk is associated only with the use of large doses of alcohol.

It should be added that even minor alcohol consumption, according to some data, can increase the risk of injury.

To drink or not to drink

Considering many of these factors, doctors around the world are not inclined to advise patients to intentionally drink alcohol "for health." The position of the World Health Organization is not completely clear: the WHO European office believes that there is no safe level of alcohol consumption, although one of the WHO reports refers to a "low–risk" level - no more than 20 grams per day five days a week. And yet, most of the world's recommendations say: if a person drinks anyway, then he can continue to drink, but in moderation. Many studies refer specifically to American norms (they are, for example, contained in the "Nutrition Guide for Americans for 2015-2020") – no more than two servings (14 grams of pure alcohol, corresponding, let me remind you, to about a glass of wine, a can of beer or a glass of vodka) per day for men and no more than one for non-pregnant women.

Alcohol is definitely not shown to pregnant women: although scientists do not have enough data to talk about the harm of small doses of alcohol for the fetus, it is not yet possible to establish a safe level of consumption, therefore it is wisest not to tempt fate. In addition, those who once had alcohol addiction or cases of alcoholism in the family, and anyone who has alcohol-related liver or pancreatic diseases, should refrain from even moderate consumption.

Portal "Eternal youth" http://vechnayamolodost.ru  24.01.2017