Everything you ever wanted to know about alcohol

Got a question about alcohol? We've put together an extensive guide to alcohol and its effects on the body. If you can't find the answer to your question here, pop us a mail at advice.centre@dnafit.com. We'll get one of our wellness team to help you find the information you need.

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What is alcohol?

Alcohol is a drug classed as a sedative due to its depressant properties. There are various different types of alcohol, however ethyl alcohol (ethanol) is the only alcohol used in beverages. In high doses, alcohol has acute and potentially lethal sedative effects. Although, in small doses (e.g. having a small glass of wine) one could experience stimulant effects. Alcohol affects every organ in the body. The effects of alcohol depend on the blood alcohol concentration (BAC) over time.

Where is alcohol found?

Alcohol is most commonly found in fermented beverages, as stated above. Alcohol is also present in many medications and cleaning products such as cough mixture and methylated spirits. Alcohol has been used for various purposes over thousands of years (both medicinally and for entertainment).

In this article, we’ll discuss alcohol in terms of a beverage that containing ethanol, created through a fermentation process of grains, fruits and other sugars. Today alcohol is widely consumed to help people to relax in social situations. While moderate consumption of alcohol shouldn’t be cause for concern, it is a highly addictive substance that can result in various health complications.   

Depending on the fermentation process, the alcohol content in the beverage will differ and can range from very low (1%) to very high (80%).

Common sources of alcohol

There are many different types of alcoholic drinks, including:

  • Beer (2–6% alcohol)
  • Cider (4–8% alcohol)
  • Wine (8–20% alcohol)
  • Tequila (40% alcohol)
  • Rum (40% or more alcohol)
  • Brandy (40% or more alcohol)
  • Gin (40–47% alcohol)
  • Whiskey (40–50% alcohol)
  • Vodka (40–50% alcohol)
  • Liqueurs (15–60% alcohol)

How many drinks per day is safe?

Men should not drink more than 14 units of alcohol per week, which amounts to about six pints of beer and women should aim to drink less than nine units of alcohol, which is roughly six 250ml glasses of wine.

What is considered moderate drinking?

Drinking alcohol occasionally (no more than six drinks per week) would be considered moderate drinking and shouldn’t do any long-term damage to your body. However, according to the recommended guidelines, drinking more than one glass of wine or beer every single night would be considered excessive drinking. This can lead to alcohol dependency and binge drinking when the weekend comes around.

What happens to your body when you drink alcohol?

A lot of processes happen inside your body when you drink alcohol. The most important thing to take into account is that as soon as alcohol enters your body, your body starts working to remove it. This is good news, because alcohol can become toxic fairly quickly if it is allowed to build up.

Firstly, alcohol is processed in the stomach where about 20% of it enters into the bloodstream, immediately going to your brain. This is why you can feel the effects of an alcohol drink relatively quickly. It doesn’t have to pass all the way through your digestive system before taking effect.

The majority of alcohol is then processed by the liver. The liver is one of the main organs associated with the breakdown and removal of toxic compounds, but there’s only so much it can take – long term excessive consumption of alcohol can lead to permanent liver damage.

Alcohol and diet


The effect of alcohol on your diet

When you are on a diet you’ll already have already set predetermined goals such as increasing your athletic ability, losing weight or building muscle. Alcohol can impair progress on all of these. It contains almost twice as many calories as protein and carbohydrates; these calories are often referred to as ‘empty’ because they are accompanied by very little nutrition. This can throw your diet out of balance. You’re taking in so many calories but getting so little out of it – excessive drinking often leads to unhealthy weight gain.

When available to the body, alcohol is used for as an energy source preferentially and blocks the oxidation of other fuels such as fat and carbs, which can contribute to weight gain.

There’s also the other side-effect of drinking and your diet as alcohol consumption can lead to poor judgement and a loss of inhibition. You may find it difficult to resist eating unhealthy foods when you are drunk, which is highly counterproductive to your weight loss goals.

By taking this, as well as taking other factors into account, can serve to explain why drinking an excessive amount of alcohol is bad for your health.

This isn’t to say that alcohol is all bad and that you should avoid it at all costs. Alcohol in moderation has been associated with reducing the risk of developing cardiovascular disease, particular in people with certain variants of the ADH1 gene.

When taking DNAFit’s DNA test, we analyse the genes associated with alcohol sensitivity and can tell you if you fall into this category.

Alcohol and genetics

Alcohol and cholesterol

If you’ve ever heard that a glass of red wine per day is good for your heart, this is truer for some people than others. Plenty of research has shown that moderate amounts of alcohol consumption can protect against risks of heart disease. For example, a study published in 1997  found that alcohol intake was associated with a protective effect against coronary heart disease in a sample of almost 130,000 people. This effect was present for both beer and wine. A second study, again from 1997, found that in both men and women, rates of cardiovascular disease were 30-40% lower in those consuming at least one drink per day compared to abstainers.

The positive effects of alcohol on your heart might be caused by alcohol affecting people’s cholesterol - specifically, alcohol might increase HDL cholesterol (often called “good” cholesterol). If alcohol is present in the blood for a long period of time, it has longer to interact with the cholesterol, and so may have a greater protective effect.

What genes are associated with your response to alcohol

The gene that interests us here is called ADH1C, which creates an enzyme that enables us to metabolise alcohol. Differences in this gene can split individuals into two camps; those with the AA genotype, called fast metabolisers of alcohol, and those with a G allele (so AG and GG genotypes), called slow metabolisers of alcohol.

Based on this, we would expect that moderate amounts of alcohol consumption would have a greater positive effect on a person’s cardiovascular risk if they were a slow metaboliser of alcohol (i.e. if they have a G allele of ADH1C). And, this is more or less what the studies find.

As an example, a study published in 2008 examined 3700 people over an eight-year period. The participants were asked how much alcohol they consumed on a regular basis, and also had blood tests to collect various measures of cardiovascular health, including HDL cholesterol. What they found was that, in those people classed as slow metabolisers, and who reported moderate alcohol consumption, there was a 64% reduction in cardiovascular disease risk.

Similar results were reported in research looking at the Framingham Offspring Study, a large study based in the US with just over 5,000 subjects, which showed, again, a lower cardiovascular disease risk with moderate alcohol consumption in slow metabolisers compared to fast metabolisers.

Similarly, a 2005 study reported a 78% reduction in cardiovascular disease risk in slow metabolisers consuming moderate amounts of alcohol compared to those who were fast metabolisers.

All of this goes to show that for slow metabolisers of alcohol, those with the G allele of ADH1C, appear to find that moderate alcohol consumption has a greater protective effect against heart disease than for fast metabolisers (AA genotypes). This doesn’t mean that alcohol is bad for fast metabolisers, just perhaps not as good as it is for slow metabolisers. And with slow metabolisers, the key word when it comes to alcohol is moderate; this is not an excuse to drink excessive amounts!

What are the side effects of alcohol?

Alcohol has both short and long-term side effects.

Short term effects of alcohol

Depending on how much alcohol you drink, the short term effects of alcohol will differ. Overconsumption of alcohol in a short space of time can eventually lead to alcohol poisoning and would result in you needing to take a trip to the hospital, so always drink wisely and responsibly.

  • Drowsiness
  • Headaches
  • Slurred speech
  • Decreased ability to feel pain
  • Slowed reaction time
  • Impaired judgement
  • Loss of inhibition
  • Warped view of reality
  • Blackouts
  • Alcohol poisoning

Long term effects of alcohol

The negative, long-term effects of alcohol outweigh the positive effects, which is why alcohol is considered bad for your health. What happens to your body when you drink too much alcohol? 

  • Liver damage
  • Cirrhosis
  • Unintentional injuries and accidents (car crashes, falls)
  • High blood pressure
  • Nerve damage
  • Permanent damage to brain cells
  • Cancer
  • Death

What is considered heavy drinking?

This differs for men and women, but only slightly. Heavy drinking is considered as:

  • Men: drinking more than four units of alcohol per day
  • Women: drinking more than three units of alcohol per day

Can you overdose on alcohol?

Yes, if you drink heavily and do not drink enough water or eat properly, resulting in your BAC being high then you can be the victim of alcohol poisoning.

Alcohol and exercise

Alcohol’s effects on muscle and metabolism

From a purely physiological perspective, the negative effect alcohol has on performance is predominately exerted through its actions on the brain – altering balance, decision making and reaction times.

Although there is evidence that alcohol affects the muscles ability to contract through altering the ability to release and re-absorb calcium, this does not appear to translate into a diminished ability to perform exercise. Nevertheless, this evidence still points towards avoiding alcohol prior to and during exercise to avoid the detrimental neural effects.

Alcohol is metabolised predominately by the liver during which imbalances in metabolic process can occur. These imbalances decrease the ability of the liver to sustain blood glucose levels causing hypoglycemia. During endurance exercise training this has the potential to significantly decrease training intensity, where the use of blood glucose is essential to maintain the training stimulus.

In addition, alcohol can have ergolytic and potentially dangerous effects if combined with high-energy caffeine containing drinks as both caffeine and alcohol are diuretics. The fact that these types of drinks are used regularly to fuel training for team and endurance sports further supports the argument for not consuming alcohol in close proximity to training.

Alcohol’s effects on recovery from training

Following competition or training the body relies on a number of processes that together aid recovery and ideally result in adaptation to repeat or improve performance during the next training session or competition. These processes include, replacing energy stores, rebuilding damaged muscles and re-hydrating.

Skeletal muscle draws a considerable amount of the energy used for most sports (especially team and endurance sports)from glycogen, the largest store of carbohydrate within the body. Alcohol consumption has the ability to inhibit the replacement of muscle glycogen after exercise through its effects on the liver and hydration.

Some evidence has indicated that a small amount of alcohol has no effect on the ability to replenish muscle glycogen as long as the recommended amount of carbohydrates are consumed, however this probably does not reflect what actually happens following training sessions. This presents a problem if hard training sessions are in close proximity to each other as glycogen will not have fully recovered, thus compromising training intensity.

Soft tissue injuries are common in endurance sports and even more so during contact sports. These are usually managed by techniques that reduce blood flow to the area (e.g. ice, compression) to minimise the inflammation that occurs. In contrast, alcohol is a potent vasodilator (increases blood flow) that has the potential to impede the repair process by causing unwanted swelling around the damaged area.

In addition to this, alcohol has a direct effect on the mechanism that regulates muscle protein synthesis, the process by which muscle growth occurs. This effect results in a reduced ability to repair damaged muscle as in soft tissue injury, but also reduces the growth of the muscle following resistance training for example. Taken together, alcohol clearly has detrimental effects on the rate of recovery from injury but also the rate of muscle growth.

Research on the effects of alcohol on training

The issue with providing recommendations on the effects of alcohol on training and recovery is that there is a lack of well-balanced literature providing conclusive evidence.

More research needs to be carried out in this area to establish exactly what the responses are. Indeed most of the research to date has been conducted in animal and cell models, hence the dilemma of providing conclusive evidence.

Recommendations when consuming alcohol

Small amounts of alcohol do not appear to affect muscle contraction, however they may still be detrimental given the lack of evidence. Best practice suggests that you shouldn't consume alcohol before training.

Alcohol consumption appears to enhance dehydration thus impacting training and recovery – best practice is to avoid alcohol until re-hydrated.

Reduce alcohol intake during periods of injury as this may help the recovery process

Alcohol reduces muscle growth. To maximise muscle growth and repair avoid alcohol consumption following soft tissue injury and resistance exercise

Once post-exercise recovery priorities have been addressed, there is no reason not to enjoy alcohol in moderation.

Should you cut out alcohol completely?

Given the culture around alcohol consumption (especially within team sports that facilitates positive social bonds), we wouldn't go as far as to advise against any alcohol consumption at all. However, because the negative effects of alcohol heavily outweigh the positives, we highly recommend limiting your intake as much as possible. Following the government recommended guidelines for drinking in moderation is the best approach.


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