Recently, the Indiana State Fair served its first alcoholic beverage since 1946. With the popularity of local breweries and wineries on the rise in Indiana – nearly a hundred of each in the Hoosier State – a reversal of the near-70 year alcohol drought at the State Fair seemed inevitable.
The logo for the Beer and Wine Exhibit 2014 at the Indiana State Fair
Meanwhile, in Indiana and beyond, many scientists are buzzing about trying to understand exactly what alcohol does to our brain. From time to time, researchers lace a rodent’s drinking water with varying amounts of ethanol in order to observe how this impacts their zig-zagging through mazes. Despite consuming alcohol for millennia, we remain remarkably ill-informed regarding how alcohol affects the nervous system. Why do we consume alcohol? How does it affect us neurologically in the short-term, and why do we keep going back for more? The answers are complex, but we are beginning to see them without beer goggles.
Going back at least to 8,000 B.C., the pages of history are splashed with examples of alcohol usage, the reasons ranging from medicinal (analgesic and antiseptic), religious (Communion wine), aesthetic (perfumes and cosmetics), preservative (safeguarding of food), industrial (fossil fuels), financial (barter) and recreational (drinking in times of merriment and sorrow to alter one’s mood). The mighty powers behind constructing the Pyramids of Giza rationed payments for their laborers in measures of beer. The Middle Ages and well beyond saw numerous reports of alcohol (primarily beer) being safer to drink than water - until the Germ Theory of Disease helped make two parts of hydrogen and one part oxygen safe to imbibe. The Royal Navy of the United Kingdom received a daily rum ration until the 1970s, when someone of importance finally became worried that operating heavy machinery might be precarious while under the influence.
Many, then, are the uses of alcohol, and diverse are instances of its enduring consumption, inherent in legions of cultures for thousands of years. For all the other ways in which the world has changed, in some ways the consumption of alcohol seems little different today. As in ancient and medieval times, we drink to please others and we drink to please ourselves.
While the liver is the key organ that metabolizes alcohol, the majority of the effects we feel after having thrown back a few (or a few too many, depending on the occasion) are primarily neurological. It is important to understand that alcohol is more than simply a depressant. Alcohol is a complex drug that causes variable effects based on the amount ingested. It affects a variety of neurological pathways and targets different structures in the brain, resulting in a cocktail of symptoms not easily explained by a single molecular alteration. After minutes of ingestion, alcohol enters the blood stream and readily crosses the blood-brain barrier, typically a highly selective barrier between the circulating blood and brain fluid, and acts on a number of receptors both directly and indirectly. Even moderate alcohol consumption can have adverse effects on sleep patterns and temperature regulation, which is controlled by a small almond-shaped structure located just above the brainstem known as the hypothalamus. While a nightcap may help you feel drowsy, larger quantities of alcohol affect REM sleep, causing restlessness and wakefulness through the course of the night.
Those who have had too much are afflicted with cerebellar defects, such as difficulty walking and impaired motor coordination. Alcohol can also do a number on the cerebral cortex, which is responsible for judgment, cognition, planning, and social interaction. Some reports suggest that alcohol can bind up to 100 independent receptors in the brain, and the various locations of these processes in the cranium determine the specific changes in behavior. Other symptoms associated with drinking include changes in memory and emotion, slurred speech, and blackouts. Small to moderate quantities of alcohol have also been reported to decrease brain volume.
Low and moderate alcohol users show a decrease in adjusted brain volume based on magnetic resonance imaging results in the Framingham Offspring Study cohort (Paul et al. JAMA Neurology 2008)
Alcohol also alters the release of numerous neuro-transmitters and neuropeptides, which are chemical messengers and protein-like molecules, respectively, involved in transmitting signals in the brain. For example, alcohol decreases the release of glutamate, the key excitatory neurotransmitter in the brain, while increasing the amount of GABA, an inhibitory neurotransmitter, potentially resulting in a slowdown of brain function. All these consequences seem negative, but there’s a catch: booze increases the production of dopamine in the “reward center” of the brain. This creates a positive feedback loop, making us want more and more of this elixir.
Indeed, there are a number of reasons why libations are such a central part of our life. Here’s a small excerpt. First and foremost, we like it! This pleasure can be explained neurologically by the activation of the dopamine-reward pathway, socially by the fact that it is an event that often brings people together (be it in times of merriment or sorrow), and psychologically by how it is a low risk/high reward activity and relieves stress, helping one cope with emotional turmoil.
If viewed from an evolutionary perspective, moderate alcohol consumption hardly affects fitness: Although the Porter in Shakespeare’s Macbeth says that drink “provokes the desire but takes away the performance,” science tells us that alcohol can bolster both. So spirits, unlike the painful fear of heights, seem no powerful threat to either survival or procreation. Additionally, the “drunken monkey” hypothesis put forth by Dr. Robert Dudley suggests that we drink because we associate alcohol with a nutritional reward, as our anthropoid ancestors primarily subsisted on ripe fruits that contained low levels of ethanol. Since moderate and chronic alcoholism are associated with a number of vitamin deficiencies, such as folate, vitamin B12, vitamin A, and calcium, I have difficulty believing that alcohol consumption is, in fact, an evolutionary hangover, but this argument has been made from time to time. However, as with most things in life, consuming alcohol in moderation can maximize its positive effects while minimizing the risk associated with consumption.
So as you weave your way to the Grand Hall to the Beer and Wine exhibition at the State Fair, right after having scarfed down your deep-fried Twinkie and a few shucks of corn, if you down that beer (or three, the limit imposed at the State Fair this year), it won’t be because you have to. You’ll swill that brew because you want to.
Contributed by: Aarti Chawla
National Institute on Alcohol Abuse and Alcoholism. http://www.niaaa.nih.gov/Diamond I, & Messing RO (1994). Neurologic effects of alcoholism. The Western journal of medicine, 161 (3), 279-87 PMID: 7975567
Németh Z, Kuntsche E, Urbán R, Farkas J, & Demetrovics Z (2011). Why do festival goers drink? Assessment of drinking motives using the DMQ-R SF in a recreational setting. Drug and alcohol review, 30 (1), 40-6 PMID: 21219496
Paul CA, Au R, Fredman L, Massaro JM, Seshadri S, Decarli C, & Wolf PA (2008). Association of alcohol consumption with brain volume in the Framingham study. Archives of neurology, 65 (10), 1363-7 PMID: 18852353