Most people can drink alcohol and even enjoy it. Svenska Dagbladet writes about the drunk monkey theory that the ability to drink alcohol once gave us an evolutionary advantage. But now for a person completely different times have come, scientists say.
Why can most people drink alcohol? One fascinating theory is called the drunk monkey, and it boils down to the evolutionary benefits that our distant ancestors had about 10 million years ago when they could eat fallen fruit, even if they were already fermenting. But not everyone in the body has the same amount of enzymes responsible for processing alcohol.
“Everyone says that Jeppe is a drinker, but nobody asks why,” such words are in Ludvig Holberg's old classic play “Jeppe on the Hill,” written back in 1722. Of course, one of the reasons, perhaps, is that he is beaten by his wife Nille, who is also cheating on him with the watchmaker. But in reality, the causal relationship is not always so easy to find out.
For example, the case is probably related to one enzyme called alcohol dehydrogenase, which is needed in order to break down alcohol and which Jeppe has. Another enzyme is also needed - aldehyde dehydrogenase. Without it, drinking alcohol would not be enjoyable. That is why the drug "Antabuse" is quite effective in preventing people from drinking, because it prevents the production of this enzyme. If you drink Antabuse in a therapeutic dose, then while drinking alcohol you will have unpleasant symptoms such as headaches, palpitations, nausea, vomiting, and so on.
This variant of alcohol dehydrogenase, according to the latest discoveries and theories of scientists, appeared in our ape-like ancestors about 10 million years ago. Mutations that remain for such a long time usually give the species some advantage in terms of reproduction or survival (or both). Therefore, there is reason to believe that alcohol has been involved in our evolution for a very long time (unless, of course, this enzyme had another important function that was not related to the breakdown of alcohol, although there is no evidence for this).
Small enough advantages for this kind of changes, mutations, to be preserved and spread in the population, as happened in people who inhabited, for example, Europe. For many Asians, the process with aldehyde dehydrogenase has not gone so far, and therefore this enzyme is often less active in them.
So what could be the advantage that kept this mutation in our ape-like ancestors and spread it? Considering that fruits were an important part of the diet of our distant relatives, it is obvious that the ability to eat easily available fallen fruits that had already begun to ferment was beneficial. The benefits of a mutation that allows you to consume fruits that have begun to deteriorate, of course, are not too great, but still quite significant if we consider it on the scale of many generations.
This is only a hypothesis that requires further proof, but it is plausible and even quite amusing: it is curious to imagine how our ancestors thought that overripe fruits can be used in a more complex way - by squeezing out delicious juice from them.
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Chimpanzees and humans separated evolutionarily between 6 and 7 million years ago. In other words, the mutation arose even earlier, which means approximately when our ancestors were just adapting to life below, on earth. These closest relatives of ours, as you know, could create and use tools, and there are theories how they could use them to consume fermentation products and alcohol-containing palm juice.
The "drunk monkey" hypothesis causes a lot of controversy, but it is really interesting, and I do not know more plausible. If it is true, inebriation might be something of a side effect, while the main evolutionary goal was to make it easier for our ancestors to find food, who now tolerated alcohol better.
There is plenty of evidence of other animals gorging themselves intoxicated, although stories of elk and fermented intoxicated apples remain in question.
But if the ability to recycle alcohol, resulting from the work of evolutionary mechanisms and natural selection, was once an advantage, how is it now? How does alcohol affect health and life expectancy? Of course, everyone knows that large amounts of alcohol are harmful, but where is the border? We know many bright personalities who drank a lot, but still lived to old age, retaining clarity of mind. A famous example is Winston Churchill. How much alcohol he actually drank is not known for sure, but he clearly did not adhere to current recommendations. His own opinion was unequivocal: he gained more from alcohol than he lost.
Another outstanding person who drank a lot, but remained active until a ripe old age, is Luigi Cornaro, who died in 1566, said to be about a hundred years old. He was an entrepreneur and tried many different things. Thanks to distant family ties, he became a nobleman. He lived on a grand scale and did not particularly respect morality, but at about 40 he decided to change. He began writing books about his new lifestyle, which included a fair amount of moderation in almost everything. He did not refuse meat, but generally ate quite a bit. This limited calorie intake clearly extends life for many species of animals.
Like Churchill, Cornaro wrote some of his best books at the age of 80, such as Conversations on the Benefits of a Moderate Life, which became very popular. Despite this moderation, he drank a lot of wine - much more than the maximum of 14 standard drinks, which is now recommended by the health authorities for men. He is said to have blown at least 20 servings, that is, about two-thirds of a bottle of wine, a day.
Of course, all these are only isolated cases, but what does science really say? How much can we drink without harming ourselves and so that the disadvantages do not outweigh the subjective advantages? It is difficult to conduct controlled experiments with alcohol in humans. As in the case of nutrition, it is impossible to carry out a double-blind experiment, when not only the subjects, but also the researchers remain in the dark about the important details of the experiment. So compared to drug research, this is very complicated.
Therefore, it is not easy to find out how much alcohol, if any, can be good for your health. There are also problems with cause-and-effect relationships. Because human experimentation is difficult to conduct, researchers often rely on polls in which people report how much they drink. But in our time of endless information leaks, one has to take into account that people often do not tell the whole truth about their alcohol habits, although to some extent this can be compensated by measuring the concentration of markers of alcohol in the blood.
There are studies on morbidity and ill health that show a so-called U-curve. This means that those who do not drink at all and those who drink a lot are at greatest risk. It is on the basis of this information that the current recommendations are based. But the problem is again in a causal relationship: perhaps today a person does not drink at all, because he used to drink too much or because he is sick, and the disease reduces his interest in alcohol. Such a problem also exists in the framework of epidemiology, where experiments are not carried out, but simply look at statistics. Medical research is most successful when a combination of different approaches - experience and epidemiology.
As for epidemiology, its methods have improved in recent years. For example, researchers resort to elegant "Mendeleev randomization." There are different genetic variants that provide different phenotypes, that is, features, both physical and psychological. It is believed that a person gets a particular genetic variant by accident, and this can be used as a kind of test based on origin in a randomized trial - dividing people into those who have a certain genetic variant and those who do not. Of course, a full-fledged randomized study will still fail, because experiments are not carried out. But this tool is being refined more and more, which means that the risk of confusion with cause and effect is reduced.
This method has recently been used to study the health effects of alcohol, building on the various aldehyde dehydrogenase variants found in people in China, where alcohol is poorly tolerated by many. People with this genetic variant have become a control group: it is known that they do not drink alcohol at all or drink very little, because they feel bad about it. With their help, it was possible to form a group of teetotalers who adhere to this lifestyle not because they are sick or were previously alcoholics. Scientists have proven that in this case, the U-shaped curve disappears: a complete rejection of alcohol can no longer be associated with some kind of disease and, in general, harm to health. But even small amounts of alcohol immediately increase the risk of getting sick.
The researchers concluded that alcohol is simply harmful, even in very small quantities. The idea that alcohol in moderation is good for health has been threatened.
But it’s not that simple. As is usually the case in such cases, the study has weak points. As you know, it is impossible to bring it to absolute completion. The weakness of the job lies in information about alcohol consumption: given how closely citizens in China are monitored, people there may not be inclined to honestly report how much they drink. True, the data collection was carried out more than ten years ago.
But genes can have pleiotropic effects, meaning they can provide more effects than originally thought. In our case, we are talking about the ability to tolerate alcohol. Perhaps a genetic variant in which a person cannot tolerate alcohol is also associated with a reduced risk of developing some kind of disease for other reasons. In addition, the study did not study red wine, and it is with this drink that various health benefits are primarily associated.
Experiments are needed to understand something for sure. Today, there is a tendency in the medical and other natural sciences to skip experiments (they are laborious and expensive) and rely on mathematical models, statistics and epidemiology. But what should you tell patients if you are a doctor? In the absence of the usual scientific knowledge, one has to act in accordance with proven experience - and since antiquity it has been known that it is beneficial to observe moderation in everything. And it might be better if your alcoholic beverage is red wine rather than vodka. Even Hippocrates believed that "wine is an amazing thing, useful for both healthy and sick person, if used in moderation and taking into account the characteristics of the individual."
Johan Frostegård