Binge drinking may cause damage to DNA
1 January 2014
A preliminary study carried out on university students in Mexico has found that weekend alcohol consumption causes oxidative damage to cell membranes and also produces signs of DNA damage in blood lymphocytic cells.
The idea of studying the oxidative effect of weekend alcohol consumption came about when researcher Adela Rendón 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. The researcher suggested to them that they should study the effects on their bodies of the weekend consumption that the students regarded as harmless.
The study analysed the effect of alcohol consumption on the lipids comprising the membrane of cells and DNA. Until now, the damage to the packaging of nuclear material in the early stages of alcohol abuse has never been documented, perhaps because most of the studies are done at later stages with people who have been consuming alcohol in an addictive way for many years. The results have been published in the journal Alcohol.
The activity of the enzyme dehydrogenase, which metabolises ethanol into acetaldehyde, acetoacetate and acetone were measured in the students. Oxidative damage is evaluated by biochemical test called TBARS, and reflects the lipid peroxidation that affects the cell 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. Therefore, there are at least two means by which free radicals are formed and which can damage cell membrane integrity.
Although the researchers expected to find oxidative damage, they were surprised by the result, as Adela Rendón explained. “We saw that the ones who drank sustained twice as much oxidative damage compared with the group that did not consume alcohol.”
They decided to continue with a test to assess whether the DNA was also affected: the comet test. They extracted the nucleus of the lymphocytic cells in the blood and subjected it to electrophoresis, which separates the contents across gel using an electric field. If the chromatin (contents of the cell nucleus) is not properly compacted and the DNA has been damaged, it leaves a halo in the electrophoresis which is called 'the comet tail'.
In the alcohol-exposed group the chromatin left a small halo that was greater than that of the control group. The results revealed damage in 8% of the cells in the control group and 44% in the exposed group. Therefore, the exposed group had 5.3 times more damaged cells.
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. “Fortunately,” Rendón pointed out, “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. The next step would be to study the re-packaging of the chromatin and the behaviour 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. Addiction involves a more complex issue socially and psychologically speaking. This is social alcohol abuse,” said Rendón, “but which causes damage in the long term and you have to be aware of that.”
The harmful consumption of alcoholic beverages is a global problem and constitutes a significant health, social and economic problem. According to World Health Organisation data, alcohol is responsible for 2.5 million deaths a year worldwide and youngsters between the ages of 19 and 25 account for 320,000 of them; it causes harm that goes beyond the drinker’s physical and mental health.
The effects of alcohol abuse have been mostly studied in people who have been consuming alcohol for a long time and who therefore display symptoms ranging from liver damage to various types of cancer, depression and disorders of the nervous system. That is why this study is pioneering because it deals with the effect of alcohol on young, healthy people.
Rendón-Ramírez A, et al. Oxidative damage in young alcohol drinkers: a preliminary study. Alcohol. 2013 Sept 27. doi:pii: S0741-8329(13)00114-6. http://www.ncbi.nlm.nih.gov/pubmed/24080163
Rendón Ramírez A, Gelover Reyes E, Couto M, Königsberg M, Castro P. <<¿Genera Cometas el alcoholismo?>> [Does alcohol abuse generate comets?] Journal: Bioquimia ISSN 0185-5751. Volume: 29; Issue: Supplement; Start page: 84; Date: 2004. http://www.medigraphic.com/pdfs/bioquimia/bq-2004/bqs041d.pdf