A new study analyzing the effects of weekend drinking among college students has found that oxidative damage on the lipids comprising cell membranes and its genetic material — DNA — is twice as high for students who drink.
The study, published in the journal Alcohol, notes that the effects of alcohol abuse have been mostly studied in people who have been drinking for a long time and who display symptoms ranging from liver damage to various types of cancer, depression and disorders of the nervous system.
This study came about when researcher Adela Rendón, Ph.D., was lecturing in clinical biochemistry at the National Polytechnic Institute in Mexico. Many of the students turning up for class first thing on Monday morning displayed a lack of attention and general malaise due to having drunk alcohol over the weekend, she noted.
She suggested that they should study the effects on their bodies of the weekend consumption, which the students regarded as harmless.
Students from Jesús Velázquez’s classes at Autonomous University of Nayarit, Mexico also participated in the study, which was specifically aimed at determining oxidative damage caused by the consumption of alcohol beverages in young people.
The students were divided into two groups: A control group made up of students who did not drink alcohol and the study group made up of those who drank on the weekends.
To make sure that they were healthy individuals without any other diseases or addictions that could alter the results of the study, the students underwent blood tests, the researcher explained. The age of the students ranged between 18 and 23. Average consumption of alcohol was 118 g, or a liter and a half of beer, for example.
The activity of the alcohol enzyme dehydrogenase, responsible for metabolizing ethanol into acetaldehyde, acetoacetate and acetone, was then measured.
Oxidative damage was evaluated by a TBARS biochemical test (the types that react to barbituric acid), and reflected the lipid peroxidation that affects the membrane due to the impact not only of the ethanol in the blood but also of the acetaldehyde produced by the action of the enzyme on the ethanol, the researcher said.
This meant there were at least two means by which free radicals are formed and can damage cell membrane integrity, she explained.
Although the researchers expected to find oxidative damage, they were surprised by the results, according to Rendón.
“We saw that the ones who drank sustained twice as much oxidative damage compared with the group that did not consume alcohol,” she said.
The researchers decided to continue with another test — called the comet test — to assess whether the DNA was also affected. They extracted the nucleus of the lymphocytic cells in the blood and subjected it to electrophoresis.
“The interesting thing is that if the chromatin is not properly compacted, if the DNA has been damaged, it leaves a halo in the electrophoresis,” she said, explaining this is called “the comet tail.”
The researchers found that the chromatin of the group that drank left a small halo, greater than that of the control group.
The results revealed damage in 8 percent of the cells in the control group and 44 percent in the exposed group, which meant those who drank had 5.3 times more damaged cells, the researcher reported.
To be able to confirm the existence of considerable damage to the DNA, the comet tail must exceed 20 nm, and that was not the case, she noted.
“Fortunately,” Rendon said, “but the fact is, there should not have been any damage at all because they had not been consuming alcohol for very long — they had not been exposed in a chronic way.”
The means by which alcohol manages to alter DNA is not yet known, she added. The next step would be to study the re-packaging of the chromatin and the behavior of complex mechanisms like the histones in these individuals.
“When we talk about youth alcohol abuse, we are referring to youngsters who drink alcohol without having become addicted,” she said.
“Addiction involves a more complex issue socially and psychologically speaking. This is social alcohol abuse, which causes damage in the long term and you have to be aware of that.”