Why Do Women Tolerate Alcohol Less Than Men?

Biologically speaking, women have  lower tolerance of alcohol. Before dealing with this issue, it’s important to understand what happens in our body when we drink alcohol and how it is metabolized. Alcohol entails biochemical processes that occur in the liver, whereby alcohol is broken down into less toxic by-products and subsequently eliminated removed from the body.

What happens when you drink alcohol?

Alcohol reaches the stomach, where it is ’emptied’ into the small intestine and therein,  it is rapidly absorbed into the bloodstream and distributed throughout the body.

In general, when consuming an alcoholic beverage, after 30 to 45 minutes, it reaches its maximum concentration in the blood and then it slowly decreases.

About 10% of the alcohol consumed is rapidly eliminated through respiration, transpiration, perspiration and urine. The remaining 90% is metabolized by the liver. This metabolism involves the action of some chemical substances known as enzymes. Among them, ADH (alcohol dehydrogenase) is quantitatively the most important one in breaking down alcohol,  and the other one is cytochrome CYP2E1, which  also breaks down some medications, and explains some of the interactions between drugs and alcohol. ADH converts alcohol into acetaldehyde, and then into acetate, which in turn, it is converted into carbon dioxide and water.

It is worthwhile noting that the liver is capable of  metabolizing only a certain amount of alcohol per hour (0.015 BAC per hour), and this does not depend on the amount consumed, nor is this ability affected by beverages (coffee, tea, drugs (caffeine) meals or exercise. Each person has his/her own rate of metabolism or clearance  and it depends on the amount of enzymes found in  his/her liver.  This explains the difference we observe in terms of the resistance to the effects of alcohol between one person and another. Such capability is genetically determined. Certain Asian populations have a lesser number of these enzymes, and a lower resistance to the effects of alcohol. They get drunk faster and easier.

While the rate of metabolism of alcohol cannot be changed, its absorption into the bloodstream can certainly be modified. This is achieved through gastric emptying. If the stomach is empty, the entry of alcohol into the intestine is faster. On the other hand, foods, especially those rich in fats, delay gastric emptying, slowing down the rate of absorption of alcohol.

People who drink alcohol excessively and on a daily basis), induce liver enzymes to stay more active. Particularly important are the enzymes CYP2E1, which not only metabolize alcohol, but also do so  with respect to paracetamol (acetaminophen). Hence, consumption of alcohol plus acetaminophen generates dramatic levels of toxicity in the liver which in turn, can result in severe liver damage. A review on this issue showed that this damage may occur even at doses of just 2.6 grams of acetaminophen daily if you have drunk alcohol (See references 1, 2)

Alcohol also affects the metabolism of a wide range of medications: increasing the effectiveness of some and decreasing it in others.

Women have less tolerance to alcohol

Women absorb alcohol faster, reaching a peak concentration in the bloodstream sooner than men. Furthermore, the amount of ADH in women is  lower. Therefore, they (except for some glorious exceptions) have less tolerance to alcohol. Some studies have determined that unlike men, the damage that alcohol produces in the liver, brain and heart, is greater.

Alcohol alters the hormonal balance of steroid hormones (sex hormones). In women, this leads to an increased amount of bioavailable estrogens, thus explaining why the prolonged use of alcohol increases the risk of breast cancer. In addition, the greater production of estrogens promotes uterine growth and increases the amount of menses.

On the other hand, in men alcohol affects their fertility. In men, excessive and prolonged consumption of alcohol reduces testosterone levels and increases the amount of estrogen. This leads to a kind of feminization of the male body that can be easily observed as a result of their mammary gland growth and  changes in the distribution of pubic hair, which is rhomboid shape (male), turning into triangular shape (female). Furthermore, low levels of testosterone can lead to a decrease in sperm production

References

  1. Black, M. Acetaminophen hepatotoxicity. Annual Review of Medicine 35:577-593, 1984.
  2. Seeff, LB; Cuccherini, BA, Zimmerman, HJ, Adler, E., Benjamin, SB Acetaminophen hepatotoxicity in alcoholics: A therapeutic misadventure. Annals of Internal Medicine 104 (3) :399-404, 1986.