Now, before you jump up and add a case of wine or beer to your next grocery pickup, hang on a minute. We’re not advocating you start consuming alcohol especially if you have to date been a teetotaler. But this is an interesting study so we did want to better understand why low-dose alcohol (LDA) may be beneficial to the brain. There are other studies that seem to support these findings, but there is just as much research too that doesn’t necessarily concur with these conclusions…all of which further piqued our interest in examining the data.
First, some science.
The 2020 study “Association of Low to Moderate Alcohol Drinking With Cognitive Functions From Middle to Older Age Among US Adults” reported on several key findings including that “moderate drinking also increases brain-derived neurotrophic factor levels, a key regulator of neuronal plasticity and development, in the dorsal striatum, whereas levels of alcohol consumption leading to intoxication do not alter the mRNA expression levels of this factor.”
I’d also read that light drinkers have a glymphatic system that was more efficient in moving cerebral spinal fluid (CSF), but high alcohol intake had adverse effects on glymphatic function that acts to sweep the brain of toxins, pathogens, inflammatory cells, and other harmful elements.2 So clearly the effects were directly related to how much alcohol is consumed.
Let’s look at another study, “Titrating tipsy targets: the neurobiology of low-dose alcohol.”3 This research discussed several key findings about alcohol and multiple areas of the brain:
1. Studies have shown that low concentrations of alcohol modulate synaptic activity in several brain regions, including the nucleus accumbens , the central nucleus of the amygdala (CeA), the lateral habenula (LHB) also known as the epithalamus, the dorsal striatum (part of the basal ganglia), and the cerebellum.
2. Low-dose alcohol also enhanced glutamatergic transmission and firing of neurons in the lateral habenula and also potentiated GABAergic transmission.
3. Multiple neurotransmitter receptors, ion channels, and signaling molecules are modulated by low dose ETOH.
4. Low-dose alcohol allosterically modulates a variety of targets with a wide range of sensitivities (including ion channels, glutamate, GABA, Glycine, nicotinic ACH and NMDA receptors). Note that with excess drinking one possible explanation for the damage to the brain associated with alcoholism is its effect on glutamate, a major excitatory neurotransmitter in the brain. When expressed at high levels, glutamate is toxic to neurons, which results in brain cell death.
5. Low-dose alcohol targets other signaling molecules, such as L1 cell adhesion molecule (L1-CAM) and insulin-like growth factor-I (IGF1). IGF1 plays an important role in energy homeostasis and neural plasticity. In the adult brain, L1-CAM plays an important role in structural and synaptic plasticity as well as in neurological diseases.
However, prior studies have shown contradictory results such as the Topiwala study conducted at the University of Oxford, U.K., which was a long-term longitudinal study that followed some 10,000 British civil servants beginning in 1985. The shocking findings included decreased hippocampal volume, especially on the right side, which is a preclinical marker of Alzheimer’s disease.
In the Topiwala study, hippocampal shrinkage in alcohol users was dose-dependent: the more alcohol one drank, the greater the atrophy. While heavy drinkers were at the highest risk compared with abstainers, even those drinking moderately had three times the odds of right-sided hippocampal atrophy and identified it as a “risk factor for adverse brain outcomes and cognitive decline.” The researchers found no protective effect of light drinking over abstinence.
At least one study also discovered that carriers of the Alzheimer’s gene, APOe4, were more likely to develop dementia if they drank any alcohol at all. In the “Relationship Between Midlife and Late Life Alcohol Consumption, APOE e4 and the Decline in Learning and Memory Among Older Adults” researchers noted “evidence that the relationship between late life alcohol consumption and the decline in learning and memory is modified according to APOE e4 status.”
They went on to state that “moderate alcohol consumption during late life was associated with an increase in learning and memory among subjects who were APOE e4−, whereas moderate alcohol consumption during late life was associated with greater decline among subjects who were APOE e4+.”
Neuroimaging studies have shown that white matter and gray matter volumes can decrease by as much as 10% in chronic alcoholics, while decades of observational studies have indicated that moderate drinking (defined as no more than one drink a day for women and two for men, equal to 1.5 oz. of 80-proof spirits, 5 oz. of wine or 12 oz. of beer) may have few ill effects. Some studies show LDA may be beneficial for brain health and reduce the risk of cardiovascular disease as well. BUT…and you knew there would be a “but”…there are other studies that show an increased risk of breast cancer for women with moderate drinking.
Does the type of alcohol make a difference?
Our friend and colleague, Dr. Ilene Rusk of the Brain and Behavior Clinic in Boulder, CO, shared with us too some interesting research about different types of alcoholic beverages and their possible neuroprotective features. One article (https://pubs.acs.org/doi/abs/10.1021/jf505075n) cites that xanthohumol, a polyphenol found in hops, has been shown to have a neuroprotective effect against oxidative-stress–induced neuronal cell damage, which could potentially slow the development of neurodegenerative disorders like Alzheimer’s and Parkinson diseases. This informative piece in addition to discussing various types of alcoholic beverages shows how red wine may even benefit the gut microbiome (https://bit.ly/3gC9MnQ), which we know also has a direct connection to the brain.
But is there a clear answer?
With the many studies we’ve discussed here along with numerous others that have been conducted, it makes it very challenging to identify a single best answer. Adding to the complicated variables are things such as lifestyle factors (e.g. high fat diets, processed foods, sodium-laden snacks) environmental influences and more that are known health hazards. While you may not think of your favorite nachos or truffle fries as a health hazard, there is no doubt that in excess these types of foods can definitely compromise our general and neurological wellbeing.
Whether you choose to enjoy a glass of red wine or a beer or abstain from any alcohol at all, these are decisions we advise you to make with your physician’s guidance specific to your health. And of course, we are always here to help if you need us.
In health and hope,
Dr. Suzanne Gazda
1 Zhang R, Shen L, Miles T, et al. Association of Low to Moderate Alcohol Drinking With Cognitive Functions From Middle to Older Age Among US Adults. JAMA Network Open. 2020;3(6):e207922. doi:10.1001/jamanetworkopen.2020.7922
2 Lundgaard, I., Wang, W., Eberhardt, A. et al. Beneficial effects of low alcohol exposure, but adverse effects of high alcohol intake on glymphatic function. Sci Rep 8, 2246 (2018). https://doi.org/10.1038/s41598-018-20424-y
3 Cui, C., & Koob, G. F. (2017). Titrating Tipsy Targets: The Neurobiology of Low-Dose Alcohol. Trends in pharmacological sciences, 38(6), 556–568. https://doi.org/10.1016/j.tips.2017.03.002