Investigating alcohol-protective variants: Genetic insights into health and behaviour

A deep dive into the genetics of alcohol consumption


Researchers have delved deep, uncovering unexpected connections between genetic factors influencing alcohol consumption and their surprising relationships with a multitude of other disorders and conditions. This unique and detailed report sheds light on the captivating journey of scientific discovery, unraveling the unexpected connections between alcohol-protective genetic variants and a diverse array of conditions and behaviors, ultimately leading to a deeper understanding of human health and genetics.

The study, conducted by a team of scientists at the University of California San Diego School of Medicine and recently published in the esteemed Lancet eBioMedicine, utilized a vast dataset of over 3 million individuals compiled by the direct-to-consumer genetics company, 23andMe, Inc.

Sandra Sanchez-Roige, corresponding author and associate professor at UC San Diego School of Medicine Department of Psychiatry, shed light on the study's significant findings. "The people who have the minor allele variant of the SNP convert ethanol to acetaldehyde very rapidly. And that causes a lot of negative effects," said Sanchez-Roige. She further elaborated that these protective variants are associated with mitigating excessive alcohol consumption and preventing alcohol use disorder, primarily influencing the quantity of alcohol an individual may consume.

The researchers focused their attention on three specific single-nucleotide polymorphisms (SNPs) and their protective alleles, which significantly impact how the body metabolizes ethanol, the intoxicating chemical found in alcoholic beverages. The study utilized genetic data to broadly classify individuals as being of European, Latin American, and African American descent, a crucial step to avoid statistical genetics pitfalls called population stratification, as noted by co-author Abraham A. Palmer, Ph.D., professor and vice chair for basic research in the psychiatry department.

Sanchez-Roige emphasized the innovative approach taken by the research team, which sought to explore possible effects of these SNP variants beyond alcohol consumption. The extensive dataset provided by 23andMe allowed the researchers to examine thousands of traits and behaviors, leading to a constellation of associations not necessarily linked to alcohol. Intriguingly, individuals with the alcohol-protective alleles exhibited generally better health, including less chronic fatigue and reduced dependency on daily assistance. However, the study also revealed unexpected associations, such as increased lifetime tobacco use, emotional eating, Graves' disease, hyperthyroidism, malaria, myopia, and several types of cancer, including skin and lung cancer, as well as migraine with aura.

Sanchez-Roige acknowledged the complexity of their findings, pointing out the potential chicken-and-egg aspect in the observed associations. "So is alcohol consumption leading to these conditions?" she pondered. Palmer added, "Or do these genetic differences influence traits like malaria and skin cancer in a manner that is independent of alcohol consumption?"

The significance of including individuals from diverse ancestral backgrounds in genetic studies was emphasized by Sanchez-Roige, highlighting the importance of a more inclusive and accurate understanding of human health. "The study of only one group of genetically similar individuals could worsen health disparities by aiding discoveries that will disproportionately benefit only that population," she noted.

As the study paves the way for future research, Sanchez-Roige expressed optimism about the potential implications for treatments and preventative medicine. "Understanding the underlying mechanisms of these effects could have far-reaching implications," she concluded.

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