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Alcohol and cholesterol
Cholesterol plays an important role in maintaining the cell structure. It essentially helps keep its shape and rigidity. When alcohol passes through the cell membrane it increases membrane fluidity.To combat this, the body increase the amount of cholesterol in the membrane to restore the fluidity back to the optimal levels. As most of the cholesterol in the body is synthesised in the liver, the cholesterol must be transported from the liver to the rest of the body. This is done the the cholesterol carrier low density lipoprotein (LDL). LDL is called ‘bad cholesterol’ because high levels of LDL have been linked to increased risk of cardiovascular disease, and although the ratios of HDL (high density lipoprotein, or ‘good’ cholesterol) to LDL are more important the LDL alone, increasing LDL and not changing HDL is obviously not good.
Alcohol and the Liver
The liver is the most commonly known site for alcohol damage in the body. The source of liver damage is increased oxidative stress and the production of a chemical called acetaldehyde.
Alcohol doesn’t cause oxidative stress directly to the liver, but it does interfere with the body’s natural defences for oxidative species, in particular, the production of free radical neutralising enzymes in the liver. This reduction in defensive enzymes leads to an increase in oxidative stress which can severely damage cells. Fortunately, the liver is extremely efficient at regenerating its cells, but frequent oxidative stress can lead to long term damage.
Acetaldehyde is a metabolite the body produces from alcohol, and is the cause of a hangover. It is a substrate for free radical production in the liver, and is a pro-inflammatory agent. The liver will convert it into acetic acid but this reaction is quite slow, and if too much alcohol is consumed the liver will become saturated with acetaldehyde and it can start to ‘leak’ out into the blood stream, where it can be transported throughout the body. Acetaldehyde has been shown to inhibit a number of enzymes in the brain and also increases oxidative stress on the body. In experiments where the enzymes which break down acetaldehyde (acetaldehyde dehydrogenase) are blocked, all the symptoms of a hangover are greatly increased.
The increased oxidative stress caused by acetaldehyde leaking from the liver can increase the risk of a number of diseases and ailments such as inflammation in joints, increases the risk of cancer, and will increase the rate at which the signs of ageing develop.
Alcohol for energy
Like fats, carbohydrates and proteins, alcohol can be used in the body as a source of energy. By weight, in contains more energy than carbohydrates, and provides roughly 7kcals/gram. Alcohol alone has no impact on insulin, but it is often consumed along with simple carbohydrates which will spike insulin.
Benefits of alcohol
Some alcoholic drinks, in particular traditional beer contain a range of B vitamins. These vitamins fulfil a wide range of roles in the body, from the production of energy to gene expression. However, as ethanol inhibits the absorption of all B vitamins, it is unlikely that these vitamins are absorbed in any significant quantities.
Red wine on the other hand has been shown to have benefits, and contains large amounts of polyphenols, and is particularly high in one called resveratrol. Aside from being a powerful antioxidant (which may help eliminate some of the oxidative stress alcohol can cause), resveratrol can stimulate cell production of nitric oxide, which causes vasodilation (veins relax and widen). This can help lower blood pressure, reduces the stress on the arteries/ veins and improves blood flow. Resveratrol can also inhibit vascular inflammation and prevent platelet aggregation, demonstrating clear benefits to the cardiovascular system.
Resveratrol has also shown an ability to reduce and prevent cancer development, especially in colorectal cancer. Like many polyphenols, resveratrol is very poorly absorbed by the digestive system, meaning that a large amount will pass to the large intestine where it will interact with our cells as well as the resident microflora. Here it has been shown to induce apoptosis (cause cell death) in colorectal cancer cells – demonstrating a clear benefit for the digestive system.
There is also evidence that people who do drink alcohol live longer healthier lifestyles than those who do not drink any, but you needs to be some common sense applied to this information. It refers to light drinkers, who may have one or two alcoholic drinks a week. They are not drinking everyday, and not in excessive amounts which will cause acetaldehyde to leak out of the liver.
Summary
Alcohol is toxic, but the damage it causes is short term and dose dependant, so your body will be able to quickly recover from the toxic effects, which will be minimal if you have a small amount to drink. This means that for most people, a glass of wine every now and then is not going to cause any harm, and could even be considered beneficial if its red wine. However, regular consumption of alcohol, and not allowing enough recovery time for complete recovery, can lead to more serious damage to the liver, which is more difficult to recover from.
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