Benefits and risks of alcoholic drinks

Alcoholic drinks can be both good and bad for you

Alcoholic drinks consist mainly of water and mostly ethyl alcohol (also called ethanol). A very small proportion is represented by other substances, naturally present or added, such as certain aromatic compounds, pigmented substances, bioactive compounds, vitamins, etc.

Ethanol, a substance that is not essential to the body, can be toxic above a certain dose. The human body is mostly able to withstand this compound without consequences on its health, by staying within the limits of moderate consumption, which means no more than two glasses a day for men and one for women. This different recommendation is due to the fact that women have a lower capacity to metabolize alcohol than men and therefore suffer more from the potential negative health effects associated with the consumption of alcoholic drinks.

Ethanol is not a nutrient, but it provides a large amount of calories in addition to those provided by food. Therefore, its excessive consumption can contribute to weight gain. Unlike other nutrients that are absorbed by the intestine, ethanol is absorbed in the first portions of the gastrointestinal tract, more precisely in the stomach and, in modest proportions, even in the mouth. Some factors can influence the timing of wine absorption and therefore the concentration of ethanol in the blood. In particular, the presence of food in the stomach reduces the absorption of wine, whereas the presence of carbon dioxide in the alcoholic drinks accelerates it. The concentration of ethanol in the blood also depends on other factors such as body composition, in particular, the amount of body water, weight, some genetic factors, the individual’s ability to metabolize alcohol and the frequency of alcohol drinking.

In addition to producing a lower quantity of the enzyme that metabolises ethanol, women tend to have a lower weight than men have less body water and more body fat. These factors make the female metabolism less efficient at metabolizing ethanol compared to men, and therefore women are usually more vulnerable to its effects. Notably, a higher blood alcohol concentration per unit of alcohol is usually observed in women compared to men, although it is not always easy to precisely predict blood ethanol concentration based on the amount that has been ingested.

Ethanol metabolism occurs by specific enzymes in the stomach and especially in the liver. The first stage of alcohol metabolism involves the formation of acetaldehyde, a compound responsible for the toxic effects of alcohol, including intoxication. The enzymes present in the liver only act in the second phase, after acetaldehyde has already had time to exert its negative effects, for instance on cognition. Since the presence of food in the stomach slows down the absorption of alcohol, the consumption of alcoholic drinks at meals is considered healthier, because it also decreases the negative effects of drinking. The ability of liver enzymes to metabolize ethanol is limited.

Finally, a very small amount of ethanol (2-10%) is eliminated unaltered through the lungs, the urine, the sweat, etc. By exploiting these elimination systems, non-invasive alcohol tests (such as those used by the police) can be carried out, can indirectly assess the proportion of alcohol in the blood.

A modest and regular amount of wine at meals makes it possible to benefit from its positive effects without exposing the body to the dangerous toxic effects of excessive doses of ethanol. However, besides the potential health benefits associated with red wine consumption, calls for caution and moderation are always necessary when it comes to alcoholic drinks.

The daily dose of alcohol that a healthy person can take without serious harm cannot be determined by strict rules, because there are so many individual variables to take into consideration. In fact, what is considered a moderate amount for one individual may be excessive for another. In addition, other alcoholic drinks that are consumed (beer, aperitifs, digestives and liqueurs in various forms) should also be considered in order to calculate the actual total number of alcohol units ingested (see Table 1).

Table 1: Amount of alcohol and caloric intake of certain alcoholic drinks.

The exact amount of ethanol contained in a specific alcoholic drink can be calculated using the ethanol concentration indicated on the label. The alcohol content is shown in degrees, a unit volume (ml alcohol in 100 ml). To obtain the grams of alcohol in 100 ml of beverage, one has to multiply the degrees by the specific weight of the wine, i.e. 0.8 g/ml and then multiply by 7 kcal/g to calculate the kcal per 100 ml.

It is important not to exceed the ability of the liver to metabolize alcohol. For instance, in a man weighing 70 kilograms, this amount is approximately 6 grams per hour. This means that it will take about two hours to metabolize all the alcohol contained in a glass of wine (12 grams). Greater attention should be paid to alcoholic drinks with higher ethanol content than wine (grappa, whisky, vodka, etc.) because these are usually consumed outside meals, i.e. when the stomach is empty.

The potential effects of alcohol on drivers’ attention greatly increases the risk of road accidents. The consumption of alcohol and energy drinks (sweet drinks with a high caffeine content) in combination is also particularly risky, since energy drinks mask the effects of alcohol giving a false sense of sobriety, when in reality the cognitive abilities are reduced by the effect of alcohol taken at the same time.

In general, abstainers have no reason to start drinking, because the bioactive substances found in wine can also be found in a huge variety of fruit and vegetable products. Particular caution is also required in specific population groups. Pregnant and nursing women should refrain completely from consuming alcohol, or otherwise drastically decrease their doses. Alcohol is distributed in all fluids and secretions and can reach the foetus through the placental barrier, as well as the new-born through breastmilk, causing serious harm. In addition, the use of alcohol should be avoided in childhood and adolescence, both because of an imperfect ability to process alcohol and because the earlier the contact with alcohol is, the greater the risk of abuse. In the elderly, the efficiency of ethanol metabolism decreases significantly together with the total body water in which alcohol can be diluted. It is therefore advisable to limit the consumption of alcohol to one glass per day.

Alcohol abuse

Chronic alcohol abuse can trigger a large variety of problems to several organs, cause nutritional imbalances and increase the risk of malnutrition. The resulting nutritional deficiencies amplify ethanol toxicity. Alcohol causes various problems both to central and to peripheral nervous systems, ranging from peripheral neuropathy and tremor to hallucinations, psychosis and dementia. Alcohol can cause acute and chronic gastritis, bleeding, ulcers, liver cirrhosis and pancreatic damage in the digestive system. Alcohol also acts on the cardiovascular system, rising blood pressure and increasing the risk of various types of heart disease. Also, moderate amounts of alcohol are involved in increasing cancer risk in different organs such as breast, mouth, pharynx and stomach. Finally, former alcohol abusers should refrain from consuming any alcoholic drinks to avoid the risk of going back to previous unhealthy drinking habits.

Alcohol use and medicines

Extreme attention must be paid to potential interactions between alcohol and medical drugs which can cause adverse reactions, including very serious ones, as well as either a reduction or an enhancement of the effects of the medications taken (see Table 2). Many drugs are metabolized in the liver by the action of the same enzymes that metabolize alcohol. The simultaneous use of these drugs with alcohol leads to a slowdown in the elimination of both alcohol and the drug, with the consequent that they both remain inside the body for longer periods of time increases the risk of overdose.

Anyone taking any medication should seek advice from their doctor about potential interaction with alcohol. The same attention should also be paid to common over-the-counter drugs, most of which suggest abstention from the concomitant consumption of alcoholic drinks.

Table 2: Main interactions between alcohol consumption and medications.

Based on the above, it is appropriate to summarise some useful rules of conduct for a healthy consumption of alcoholic drinks:

• If you want to drink alcohol, do so in moderation, either during meals or immediately before and after a meal.
• Give preference to those drinks that have a lower alcohol content (wine and beer).
• Alcohol consumption during childhood, adolescence, pregnancy and breastfeeding must be avoided.
• Elderly people should be particularly cautious regarding the amount of alcohol they drink.
• Avoid drinking alcohol before driving a vehicle or before using sensitive or dangerous equipment.
• Avoid drinking whenever you need to maintain your attention level, self-criticism and motor coordination at a high degree.
• Avoid or reduce alcohol consumption when taking medication (including many over the counter ones).

To conclude, there are many false beliefs about alcohol. First of all, it is not true that alcohol helps digestion: on the contrary, it slows it down and induces gastric hypersecretion and altered emptying of the stomach. It is not true that wine is good for the blood: it is instead true that alcohol abuse can cause various forms of anaemia and increased serum triglycerides concentrations. Also, alcoholic drinks do not quench one’s thirst but rather, they can dehydrate the body. Alcohol requires water for its metabolism and increases water losses through the urines by inhibiting the secretion of antidiuretic hormones. It is not entirely true that alcohol heats up the body. In fact, the vasodilation that it causes is responsible only for a temporary and deceptive feeling of heat, which quickly leads to a loss of heat and further cooling of the body. This phenomenon can, in an unheated environment, increase the risk of frostbite. Alcohol does not help to recover from a shock: on the contrary, by causing peripheral vasodilation, it causes a decreased flow of blood to the internal organs, especially to the brain. Finally, alcohol cannot increase muscle strength. By being a sedative, it can only produce a decreased sense of fatigue and pain. In addition, only part of the calories of alcohol can be used for muscle work.

That’s all folks, I hope this post will help you understand better the risks associated with the use of alcohol and to drink more wisely!