To Drink or Not To Drink: The Aging Brain and Alcohol

Summary: A new paper raised the question, can limited alcohol consumption help stave off age related cognitive impairment?

Source: PLOS.

Wisdom and grace come with age, but so do mental slowing and increased risk for dementia. As the elderly population continues to grow, preserving brain health to maintain independence and quality of life into older age is a pressing concern. Researchers have identified some unsurprising factors that reduce one’s risk for cognitive decline, including education, exercise or a healthy diet. But a more controversial question that continues to perplex scientists is whether alcohol consumption might also stave off cognitive impairment with age.

The aging brain on alcohol

Image shows a glass of wine.
Although resveratrol minimizes dementia pathology in animals, the extremely high doses required make it unlikely to be the primary source of neuroprotection from alcohol. NeuroscienceNews.com image is adapted from the PLOS news release.

Anyone who’s experienced the fatigue and brain fog that follow a night of heavy drinking doesn’t need science to explain the dangers of excessive alcohol intake. These health risks may be especially impactful to the older brain, which is already particularly vulnerable to environmental stressors. However, in moderation, a glass of wine or beer may not only be harmless, but may in fact also confer resilience to the aging brain against cognitive decline. Numerous studies have reported that moderate drinking is associated with lower rates of dementia, better cognitive performance, and slower decline in memory and executive functions. Yet, not all studies support the notion that a nightcap can help keep the brain sharp into late life. These discrepant findings raise two obvious questions. First, why are some patterns of drinking neurobiologically healthy, while others are toxic? And second, how can we better identify drinking behaviors that promote the healthiest trajectories of cognitive aging?

Neuroprotective in moderation, neurotoxic in excess

In excess, alcohol works as a neurotoxin on many levels. Studies in animals have shown that binging on ethanol kills neurons and impairs neurogenesis–the birth of new neurons–in the hippocampus, a region critical to creating new memories. Furthermore, alcohol-induced dementia results from brain damage that occurs with prolonged alcohol abuse. The reasons for the observed benefits of alcohol are less clear. In contrast to binge drinking, moderate alcohol intake increases neurogenesis and may help counteract oxidative stress in neurons. It’s well documented that what’s good for the heart is good for the brain, and indeed, vascular dysfunction often co-exists with or precipitates many forms of dementia. A prevailing theory is that the neuroprotective properties of drinking stem largely from their positive effects on cerebrovascular health. Alcohol can reduce risk for stroke and heart disease, lower blood pressure and increase HDL (“good”) cholesterol. However, some evidence that wine is more strongly neuroprotective than other forms of alcohol suggests that resveratrol, a potent antioxidant found in red wine, may also play a role. Although resveratrol minimizes dementia pathology in animals, the extremely high doses required make it unlikely to be the primary source of neuroprotection from alcohol.

Unraveling healthy drinking patterns for the aging brain

For our aging population to reap the greatest benefit from alcohol, it will be essential to determine patterns of healthy drinking that are optimized for the individual. This will require, foremost, a comprehensive understanding of how alcohol distinctly affects you versus me based on our genetics, sex or lifestyle. For example, alcohol has been found to differentially influence brain structure and risk for dementia or cognitive impairment for those with and without the apolipoprotein E4 gene, a strong risk factor for Alzheimer’s disease. Furthermore, studies have inconsistently reported sex differences in how drinking influences cognitive decline, which may be explained by differences in how men and women metabolize alcohol.

Despite overwhelming evidence that moderate alcohol intake can be healthy for the aging brain, there are striking incongruences across findings–which may be due to differences in study design or confounding factors­–that muddle our understanding of alcohol’s benefits. ‘Survival bias,’ in which healthier individuals participate in studies for longer, is an unavoidable complication in longitudinal studies of aging. This could significantly skew results if unhealthy drinkers drop out early, leaving only “healthy” drinkers to be studied in very old age. Furthermore, most human studies on alcohol and brain aging rely on observed associations, which can be replete with confounding factors. For instance, it’s known that drinkers tend to live more healthy lifestyles (e.g., they may exercise more or follow a Mediterranean diet), or may drink more often simply because they’re more socially active, which alone is known to be brain-healthy. What’s more, effects of alcohol on cognitive aging may depend on the type of alcohol consumed, how alcohol intake is measured, or the definition of “non-drinkers.” Many studies group life-long abstainers together with quitters, who may avoid alcohol due to poor health or may have developed health problems from alcohol abuse. However, my postdoctoral adviser Linda McEvoy, who studies effects of alcohol on brain aging at UC San Diego, explains that “Randomized controlled trials offer a better alternative to more definitely answer the question of how moderate alcohol intake affects cognitive function. Such trials have demonstrated beneficial cardiometabolic effects in those randomized to drink moderate amounts of alcohol.”

A prescription for alcohol?

Despite some uncertainties in the research so far, it appears that regular moderate drinking is unlikely to be hazardous to cognitive function and may even support healthy brain aging. Until we have further clarification, McEvoy offers some advice to those hoping to preserve brain health into late life: “If a person consumes alcohol, I would advise drinking moderate amounts of alcohol (one or two drinks) with dinner. If the person does not drink, I would not advise starting. Some individuals have a hard time controlling the amount they drink, and heavy drinking has detrimental effects on brain health and cognitive function.”

About this neuroscience research article

Source: Emilie Reas – PLOS
Image Source: NeuroscienceNews.com image is adapted from the PLOS news release.
Original Research: Aberg E, Hofstetter CP, Olson L, Brene S. (2005). Moderate ethanol consumption increases hippocampal cell proliferation and neurogenesis in the adult mouse. Int J Neuropsychoparmacol. 8(4):557-67. doi:10.1017/S1461145705005286

Anstey KJ, Mack HA, Cherbuin N. (2009). Alcohol consumption as a risk factor for dementia and cognitive decline: meta-analysis of prospective studies. Am J Geriatr Psychiatry. 17(7):542-55. doi:10.1097/JGP.0b013e3181a2fd07

Antilla T et al. (2004). Alcohol drinking in middle age and subsequent risk of mild cognitive impairment and dementia in old age: a prospective population based study. BMJ. 329(7565):539. doi:10.1136/bmj.38181.418958.BE

Beydoun et al. (2014). Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis. BMC Public Health. 14:643. doi:10.1186/1471-2458-14-643

Davis BJK et al. (2014). The Alcohol Paradox: Light-to-Moderate Alcohol Consumption, Cognitive Function, and Brain Volume. J Gerontol A Biol Sci Med Sci. 69(12):1528-35. doi:10.1093/gerona/glu092

den Heijer T et al. (2004). Alcohol intake in relation to brain magnetic resonance imaging findings in older persons without dementia. Am J Clin Nutr. 80(4):992-7.

Ganguli M, Vaner Bilt J, Saxton JA, Shen C, Dodge HH. (2005). Alcohol consumption and cognitive function in late life: a longitudinal community study. Neurology. 65(8):1210-7. doi:10.1212/01.wnl.0000180520.35181.24

Hines LM, Rimm EB. (2001). Moderate alcohol consumption and coronary heart disease: a review. Postgraduate Medical Journal. 77(914):747-52. doi:10.1136/pmj.77.914.747

Krueger KR et al. (2009). Social engagement and cognitive function in old age. Exp Aging Res. 35(1):45-60. doi:10.1080/03610730802545028

Lap et al. (2009). Heterogeneity in Red Wine Polyphenolic Contents Differentially Influences Alzheimer’s Disease-type Neuropathology and Cognitive Deterioration. J Alzheimers Dis. 16(1);59-72. doi:10.3233/JAD-2009-0916

Liao SL, Chen WY, Raung SL, Chen CJ. (2003). Ethanol attenuates ischemic and hypoxic injury in rat brain and cultured neurons. Neuroreport. 14(16):2089-94. doi:10.1097/01.wnr.0000093754.20088.bc

Nixon K, Crews FT. (2002). Binge ethanol exposure decreases neurogenesis in adult rat hippocampus. J Neurochem. 83(5):1087-93.

Obernier JA, Bouldin TW, Crews FT. (2002). Binge ethanol exposure in adult rats causes necrotic cell death. Alcohol Clin Exp Res. 26(4):547-57.

Panza F et al. (2012). Alcohol consumption in mild cognitive impairment and dementia: harmful or neuroprotective? Int J Geriatr Psychiatry. 27(12):1218-38. doi:10.1002/gps.3772

Reas ET, Laughlin GA, Kritz-Silverstein D, Barrett-Connor E, McEvoy LK. (2016). Moderate, Regular Alcohol Consumption is Associated with Higher Cognitive Function in Older Community-Dwelling Adults. J Prev Alzheimers Dis. 3(2):105-13. doi:10.14283/jpad.2016.89

Ridley NJ, Draper B, Withall A. (2013). Alcohol-related dementia: an update of the evidence. Alzheimers Res Ther. 5(1):3. doi: 10.1186/alzrt157

Stampfer MJ, Kang JH, Chen J, Cherry R, Grodstein F. (2005). Effects of moderate alcohol consumption on cognitive function in women. N Eng J Med. 352(3):245-53. doi:10.1056/NEJMoa041152

Truelsen T, Thudium D, Gronbaek M, Copenhagen City Heart Study. (2002). Amount and type of alcohol and risk of dementia: the Copenhagen City Heart Study. Neurology. 59(9):1313-9

Cite This NeuroscienceNews.com Article

[cbtabs][cbtab title=”MLA”]PLOS “To Drink or Not To Drink: The Aging Brain and Alcohol.” NeuroscienceNews. NeuroscienceNews, 24 February 2017.
<https://neurosciencenews.com/alcohol-brain-aging-6156/>.[/cbtab][cbtab title=”APA”]PLOS (2017, February 24). To Drink or Not To Drink: The Aging Brain and Alcohol. NeuroscienceNew. Retrieved February 24, 2017 from https://neurosciencenews.com/alcohol-brain-aging-6156/[/cbtab][cbtab title=”Chicago”]PLOS “To Drink or Not To Drink: The Aging Brain and Alcohol.” https://neurosciencenews.com/alcohol-brain-aging-6156/ (accessed February 24, 2017).[/cbtab][/cbtabs]

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