Physiological Impacts of AlcoholBy C Kohn, Waterford Agricultural Sciences

Alcohol

Alcohol for consumption has the same molecular structure as fuel ethanol: CH3CH2OH

Alcohol is poisonous to the human bodyMany of the effects associated with consuming alcohol are actually a

result of either the toxic impact on the body or the body’s method of coping with the toxin

When alcohol is consumed, the body immediately tries to eliminate it.

Alcohol is also a drug and can form both dependency and addiction

Pathway of Alcohol The route taken by alcohol during consumption is as follows: 1. Mouth & Esophagus – alcohol is diluted by saliva before

being swallowed. Some is immediately absorbed2. Stomach – more alcohol is absorbed here, irritating the

lining of the stomach and increasing the acidity 3. Small Intestine – any remaining alcohol is passed here and

is the site of most alcohol absorption 4. Bloodstream – alcohol quickly diffuses through the body,

affecting almost all cells5.Brain - these cells are more susceptible because they are

usually protected from toxins by the blood-brain barrier6. Liver – blood-alcohol is metabolized in two stages and then

respired into CO2, H2O, and fatty acids. 7. Excretion via urine, the lungs, and sweat.

Steps of MetabolismThe metabolism of alcohol is the process in which the body

converts alcohol into a less toxic substance.

Alcohol metabolism (processing) has three steps1. Consumption – getting the liquid into your body2. Absorption – absorbing the alcohol into your bloodstream3. Processing – converting the I) alcohol into

II) acetaldehyde , then III) acetate (or acetic acid) and finally into fatty acids, carbon dioxide, and water

Consumption

Consumption – mouth and esophagus20% of consumed alcohol is

immediately absorbed into the bloodstream before reaching the rest of the gastrointestinal tract

Alcohol is an irritant to the sensitive lining of the esophagusExcess consumption can

significantly raise your risk of esophageal cancer

AbsorptionAlcohol is absorbed into the blood through the stomach walls

The emptier the stomach, the faster the absorption, the greater the impact, and the more pronounced the side-effects

Absorption of alcohol also irritates the lining of the stomach, leading to some symptoms commonly associated with a hangover (nausea, vomiting, diarrhea)

This also accelerates productions of hydrochloric acid in the stomach, leading to the ‘upset stomach’ feeling common with consumption and/or hangover If HCl secretion increases too rapidly or too high (or both), nausea and vomiting

pathways are triggered. If vomiting does not occur, diarrhea is more likely for the same reason

Alcohol not absorbed by the stomach is absorbed in the small intestine (where most absorption occurs)

AbsorptionOnce in the bloodstream, alcohol is rapidly distributed throughout the body

Different tissues absorb alcohol at differing rates

E.g. muscle absorbs alcohol more rapidly than fatPeople with higher percentages of body fat will absorb alcohol less quickly, lengthening

the time it circulates in the bloodstreamWomen physiologically have a higher body fat percentage than men, typically increasing

the impact of alcohol on their bodies

Body size also is a factor – the smaller the body, the more concentrated the effects will be (because alcohol will be a bigger proportion of the bodily fluid in a smaller person)

Rate of absorption is also affected by rate and type of consumptionFaster consumption, faster absorption Carbonated beverages also increase the rate of absorption – includes champagne, wine

coolers, and drinks made with soda

Processing Alcohol is processed by the liver as it arrives from the bloodstream

The liver produces enzymes called alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH).Alcohol metabolism via ADH produces a secondary product more toxic than

alcohol itself – acetaldehyde

Acetaldehyde is then converted into acetate by ALDH

Acetate is digested into fatty acids, CO2, and water Fatty acids, when digested, create

7 calories per gram of alcohol ‘Beer gut’ has some truth to it

Overview of Processing1. Alcohol arrives at the liver via the bloodstream2. ADH turns alcohol into acetaldehyde

This is the “bad” version

3. ALDH converts acetaldehyde into acetate This is the “good” version that can be broken down

4. Acetate is converted into CO2, H2O, and fatty acids by liver cell mitochondria. If fatty

acids accumulate too fast, cirrhosis can occur

Effects of AlcoholImpaired JudgmentAmnesia Anxiety“Breaking the Seal” –

Increased Urination

Flushing (Red-Faced)Disrupted BalanceHangovers, Nausea, &

Dehydration

Impaired Judgment Alcohol depresses the central nervous system

This means that alcohol slows the rate at which the nervous system can function and communicate

This will prevent all neurological processes from occurring at the normal rate or extent ranging from judgment to control of bodily function.

Structures of the brain affected include the frontal lobe where rational decision making and judgment occurs.

Consumption of alcohol will also cause increased self-confidence as well as decreased judgment – a very bad combination. Those that are too drunk to drive are less likely to be able to make this determination as they

drink more Those that are too drunk too drive will also feel more confident in their own ability to safely do so

(despite the contrary being true)

AmnesiaBecause the central nervous system is impaired, the process of

creating and storing memory is also impaired.

This can lead to short-term amnesia – excess alcohol consumption can cause people to be unable to form memories during consumption to varying extents.

Anxiety

Part of the brain, called the amygdala, regulates human emotion The amygdala is responsible for creating emotion appropriate for

a circumstance

Because alcohol depresses the central nervous system, the emotional regulatory function of the amygdala will also be impaired.

This can lead to anxiety, anger, frustration, lust, and other primal human emotions to become over- or under-expressed.

“Breaking the Seal”“Breaking the seal” and Water Loss

A common myth associated with alcohol consumption is that if you urinate once, you will have to urinate constantly – this is called “breaking the seal”

In reality, you’ve ‘broken the seal’ as soon as you have your first sip

Alcohol affects urination in 3 major ways – Alcohol is a diuretic, causing cells to shed waterAlcohol interferes with water reabsorption in the kidneys, causing excess water

to be moved to the bladderAlcohol causes stretch receptors ‘miscalculate’ the amount of urine in the bladder,

making it feel fuller than it is.

A combination of excess water lost, reduced water reabsorption, and a miscalculating bladder creates the need to urinate more frequently with greater consumption.

Thinned BloodAlcohol is a blood thinner

Alcohol has a lower density than waterThis is why alcohol floats on top of water

Consumption and absorption of alcohol will reduce the thickness of your blood.

Moderate consumption of alcohol (< 2 drinks per day) by legal adults can actually improve heart health by lessening the work required to pump bloodThinner blood is easier to pumpDo not self-diagnose!

FlushingA common symptom of inebriation is flushing, or being “red

faced”

Flushing in the face is due to an excess of acetaldehyde in the body, a decrease in the ALDH enzyme, or both.

Because acetaldehyde is more toxic to the body than the alcohol itself, it can cause an inflammation response similar to injury or infection in skin blood vessels.

Lost BalanceBalance is regulated by the semicircular canals inside your ear.

The semicircular canals are looped structures that are filled with fluid called endolymph

The movement of fluid inside these loops tells your body your position and orientation in space

Alcohol thickens this fluid, reducing theability to sense movement.

The sensory system responsible forsensing movement is now less sensitive, causing stumbling and loss of coordination and balance.The cerebellum (muscle coordination

center of the brain) also is impaired

HangoversA hangover is the ill-effects

experienced by excess alcohol consumption after the ‘high’ of alcohol has worn off.

Symptoms of a hangover include:FatigueDehydrationNausea & Stomach Irritation Headache

Fatigue

The exhaustion associated with excess consumption is due to alcohol’s inhibition of glutamineGlutamine is a bodily stimulant whose production is inhibited by alcoholWhen the effects of alcohol wear off, glutamine production is increased to

compensate for previous inhibitionThis causes a drinker to wake more in their sleep as glutamine production

increases, preventing the deepest and most restful stages of sleep

Glutamine rebound can also lead to tremors, anxiety, and restlessnessGlutamine, like caffeine, is a stimulantExcess glutamine production is going

to have effects similar to excess caffeine consumption

Dehydration Alcohol is a diuretic and causes cells to shed water.

Alcohol also interferes with the kidney’s ability to regulate water balance in the body Job of an aquaporin protein is to regulate reabsorption of water filtered out of the blood by

the kidney. Vasopressin is a hormone that regulates whether or not an aquaporin channel is open

Alcohol inhibits the function of vasopressin, limiting its ability to open aquaporin channels that would let filtered water back into the bloodstream This causes water to be moved to

the bladder at an increased rate This coupled with the diuretic effects

of alcohol leads to a dehydrating effect when consumed

Opened by

Vasopre

ssin

Nausea & Stomach Ache

Stomach Irritation is largely due to excess production of HCl in the stomach as a result of absorption into the bloodstream through the stomach lining.

Excess hydrochloric acid increases the acidity of the stomach, creating the ‘sour stomach’ feeling in a very literal way

If the pH of the stomach drops too much or too fast (or both), it will cause vomiting, diarrhea, or both.This can also be caused by a ‘fight or flight’ response of the body

due to the poisonous nature of alcohol

Headache

A headache can be due to numerous effects of alcohol, including – Inflammation of blood vessels, creating pressure in the skullDehydrationAcetaldehyde’s presence in the blood Increased stimulation and anxiety caused by glutamine

resurgence Stress from nausea A combination of all these and more

Cures to a HangoverThere is only one truly effective cure to a hangover – TIME

Pain relievers that do not contain acetaminophen can lessen perceived pain but not actual damage (aspirin can cause increased liver damage)

Caffeine is a diuretic and will compound damage caused by water lost and dehydration

“Hair of the Dog” or drinking again in the morning to lessen a hangover, only worsens the problem while lessening the perception of it (for the time being)

Cures to Inebriation

Similarly, you cannot “sober up” with anything other than time. Caffeine will not reverse the depression of the central nervous

system, thicken your blood, restore your balance, or negate any other effects of inebriationWhat’s worse, mixing an ‘upper’ with a ‘downer’ (caffeine with

alcohol) can cause the brain to send conflicting signals to organs such as your heart and lungs.

Stimulant/alcohol combinations can lead to heart or lung failure. Consuming food to sober up will not reduce the amount of alcohol

already in your bloodstream Additionally, you cannot ‘fool’ a blood alcohol meter.

Long Term Effects of Excess Consumption

Tissue damage – alcohol is an irritant to the mouth, throat, and stomach and can raise the risk of cancers to these structures

Liver Damage – the liver can be overwhelmed by fatty acid, causing it to swell and lose its ability to filter the body of other toxins

Brain damage – alcohol can permanently damage brain cells, particularly in brains that are still developing and maturing (the brain does not finish maturing until age 20-25).

Weight gain – alcohol has 7 calories per gram. This is almost as high as pure fat (9 cal) and higher than carbohydrates (4 cal/g)

Skin Damage – the conversion of alcohol into acetaldehyde causes inflammation. Excess consumption will cause excess inflammation that can lead to the rupture of

blood vessels in the skin creating blotchy scarring. Accidents – impaired judgment, lost coordination, and an increased sense of

confidence is a deadly and all-too-often fatal combination.

Review ConceptsHow alcohol is treated by the body.Similarities between fuel ethanol and alcohol for

consumption.Percent of alcohol absorbed by the mouth and esophagus. How alcohol upsets the stomach.How alcohol consumption affects men and women differently. How alcohol is processed by the liver (including the enzymes

needed and the intermediate forms of alcohol formed during metabolism by the liver).

Final products created by the metabolism of alcohol. How alcohol affects: judgment; emotion; memory; the skin;

balance; urination; fatigue; hangovers (include the effect on the primary structures needed for each consideration).