There is no doubt that heavy alcohol consumption is harmful to your health, but moderate alcohol intake recommendations have historically been vague. The British Medical Journal just published a study that counters the notion that a drink a day may be protective to your health, as previous studies have suggested. Instead, it shows that even moderate alcohol consumption can cause detrimental structural changes to the brain.
Exactly what constitutes “moderate drinking” is variable; some studies refer to it as less than one drink per day, while others refer to it as three or four drinks per day. This study defined moderate drinking as 7 to 14 units per week for women, and 7 to 21 units per week for men. Each unit of alcohol is equivalent to approximately 10mL of alcohol, which translates 14 units per week into just 5 large glasses of wine, and 21 units into 7 large glasses of wine.
The study followed a total of 550 men and women over a 30-year period, and alcohol intake and cognitive function were measured. MRI scans of each participants’ brain were also measured. The study observed structural changes in the hippocampus - the area of the brain associated with memory. In people who were deemed abstinent, 35% had shrinkage of the hippocampus. That figure doubled to 65% in people who drank an average of 7 to 14 units per week (less than a drink per day) and 77% for those who drank 30 or more units a week (less than two drinks per day).
The MRI also revealed structural changes in the white matter of the brain. This is the part of the nervous system that insulates and helps to relay signals from the brain to the rest of the body. It was found that those who drank moderately had less white matter integrity than those who did not drink. These participants’ performed poorly on lexical fluency, a psychological test in which participants have to say as many words as possible from a category in a given time period.
This study shows that compared to those who completely abstain from drinking, moderate alcohol intake results in steeper cognitive decline. No protective effect of light drinking over abstinence was found. Given the complexity of alcohol’s effects on the body, try to keep your intake to no more than a drink a day for optimal health. This applies to both men and women.
Topiwala, Anya, Charlotte L. Allan, Vyara Valkanova, Enikő Zsoldos, Nicola Filippini, Claire Sexton, Abda Mahmood, Peggy Fooks, Archana Singh-Manoux, Clare E. Mackay, Mika Kivimäki, and Klaus P. Ebmeier. "Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study." BMJ. British Medical Journal Publishing Group, 11 May 2017. Web. 26 June 2017.
Kloner RA, Rezkalla SH. To drink or not to drink? That is the question. Circulation. 2007; 116:1306–17.