The Truth About Alcohol

  • 16 Aug 2009
  • Reading time 13 mins
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Does a small amount of alcohol do you good and, if so, how much is too much? Find out the truth about alcohol.

Good for the Heart?

One plus for alcohol in moderation is the well-established finding that it increases HDL (good) cholesterol. This is true for both beer and wine, and seems to relate more to the quantity drunk than the type of drink. Red wine, in particular, may confer additional cardiovascular benefits by virtue of being high in proanthocyanidins, the antioxidants found in grapes and berries. Alcohol itself, however, is an oxidant. Another potential benefit of alcohol is a mild reduction in platelet aggregation – in other words, it makes your blood thinner.

This occurs because alcohol blocks the formation of prostaglandins from essential fats. For the body to make use of essential fats, however, these fats must be converted into their active compounds – a process which is blocked by alcohol. So the combination of being essential fat deficient and drinking alcohol is especially bad. The bone of contention is the dose: does a glass of wine a day confer benefit? Most reviews conclude there is a clear risk reduction from light or moderate drinking, the positive benefit primarily for red wine, high in resveratrol. However some studies show a link between moderate to heavy alcohol consumption and increased blood pressure and incidence of strokes. Diabetes risk also appears to be lower with light or moderate drinking, but not heavy drinking. Since the overall effect of alcohol might impact on increased mortality, it appears that drinking lightly, less than a drink a day, confers protection both from cardiovascular disease and stroke, but also mortality, compared to abstainers.

Bad for the Liver

Alcohol is detoxified by the liver, which involves a liver enzyme called alcohol dehydrogenase, but when you consume more alcohol than this enzyme can handle the liver will instead metabolise the alcohol to chloral hydrate, also known as Mickey Finn drops, which knocks you out. Normally alcohol is metabolised to acetaldehyde by an enzyme called acetyldehyde oxidase, and, from there, to harmless chemicals that can be excreted from the body. But if you overload this second enzyme you end up with too much circulating acetaldehyde. This very acidic and toxic substance leads to ketoacidosis – what we commonly refer to as a hangover: namely headache, nausea, mental and physical tiredness, and aching muscles.

Acidosis occurs when the blood has become too acid, in this case through the toxic metabolites of alcohol. Acidosis is a cause of premature ageing and osteoporosis and can lead on to other disease states. It is a frequently reported finding in excess alcohol consumption. The liver enzyme responsible for detoxifying alcohol depends on a good supply of antioxidant nutrients, especially vitamin C. Yet, even before alcohol gets to the liver it has negative effects in the gut where it acts as an intestinal irritant. This increases the risk of increased intestinal permeability, which in turn increases the risk of allergic reactions to absorbed particles of incompletely digested food and to the ingredients within the alcoholic drink itself. For this reason, many beer and wine drinkers become allergic to yeast. About one in five people, on testing, have this sensitivity.

In addition, wine drinkers may become sensitive to sulphites, which are added to grapes during the winemaking process to control their fermentation. Sulphites are also found in exhaust fumes, and the liver enzyme that detoxifies sulphites is dependent on molybdenum, a trace element that is frequently deficient in the diet. Organic, sulphite-free wines and champagne are better for you, the latter of which has the added bonus of being yeast-free.

Alcohol Destroys Nutrients

There is little question that alcohol acts as an ‘anti-nutrient’. Although some forms of alcohol (such as stout or red wine) do deliver a few nutrients, alcohol itself is a potent destroyer of these same nutrients. It also affects your nutrient intake by disturbing the digestion and absorption of food, and suppressing appetite. Chronic alcohol consumption leads to multiple deficiencies of nutrients, including B vitamins, vitamin C, magnesium and zinc. Having alcohol with a meal also reduces the amount of zinc and iron you absorb from your food.

Gut Problems

Alcohol irritates your intestinal tract, making it more permeable to undigested food particles, and increasing the chances of an allergic reaction to substances in both the food and the alcohol. This is why many beer and wine drinkers become allergic to yeast. Wine drinkers may also become sensitive to sulfites, which are added to grapes to control fermentation. Better choices include organic, sulfite-free wines and champagne – the latter of which has the added bonus of being yeast-free. As well as increasing intestinal permeability, alcohol wreaks havoc on intestinal bacteria. It has been reported to convert gut bacteria into secondary metabolites that increase proliferation of cells in the colon, initiating cancer.

It can also be absorbed directly into the mucosal cells that line the digestive tract and converted into aldehyde, which interferes with DNA repair and promotes tumors. In addition, some alcoholic drinks contain the carcinogen urethrane. Urethrane has been found in bourbon whiskeys, European fruit brandies such as cherry brandy, cream sherries, port, sake and Chinese wine, but not in vodka, gin and most beers.

Alcohol and Cancer

There is no question that alcohol is a powerful carcinogen. It damages intestinal bacteria, converting them into secondary metabolites that increase proliferation of cells in the colon, hence initiating cancer. It can also be absorbed directly into the mucosal cells that line the digestive tract, and is converted into aldehyde, which interferes with DNA repair and promotes tumour development. In addition, alcohol consumption may lead to nutritional deficiencies, affecting the absorption of cancer-fighting nutrients.

When a number of studies were ‘pooled together’ to evaluate a total of 322,647 women, researchers found a greater risk of breast cancer among those who drank alcohol and concluded that, in women who consume alcohol regularly, reducing alcohol consumption is a potential means to reduce breast cancer risk. A recent study in the Journal of the American Medical Association (JAMA. 2011;306[17]:1884-1890) reported that a low level of alcohol consumption (5.0 to 9.9 grams per day, equivalent to 3-6 glasses of wine per week) was modestly but statistically significantly associated with a 15 percent increased risk of breast cancer.

Also, women who consumed at least 30 grams of alcohol daily on average (at least 2 drinks per day) had a 51 percent increased risk of breast cancer compared with women who never consumed alcohol. The study authors suggested this may be due to alcohol’s effect on raising oestrogen levels in circulation, probably due to decreasing the liver’s capacity to detoxify oestrogens. Another study reported a suppression of the immune system during acute alcohol intoxication as well as an increased risk of cancers ‘metastasising’ or spreading, due to decreased activity of the natural killer immune cells (which protect against both cancer cells and infections).

A 2006 review of more than 20 research studies, published in the medical journal Lancet Oncology, came to the conclusion that there is an especially strong relationship between alcohol consumption and cancers of the breast, colorectum, liver, oral cavity, pharynx,larynx and oesophagus. There is also a suspected link for cancers of the pancreas and lung. According to the 2007 report from the World Cancer Research Fund, the evidence that all types of alcoholic drink are a cause of a number of cancers is now stronger than it was in the 1990s and they cite hundreds of studies associating alcohol with increased cancer incidence. The question is how much is too much? The World Cancer Research Fund advises that even small amounts of alcoholic drinks should be avoided and, if consumed at all, should be limited to no more than two drinks a day for men and one drink a day for women. For breast cancer, the risk increases at even one drink a day, and less if your homocysteine level is high and/or you have low levels of folate, in which case the risk increases above three drinks a week.

Another study in Finland, which followed over 27,000 men for up to eight years, found that the risk of colorectal cancer increased with the amount of alcohol consumed.

Alcohol and Weight Gain

In a survey of over 19,000 non-obese women followed up over 13 years, those who drink a light to moderate amount of alcohol appear to gain less weight and have a lower risk of becoming overweight and obese than non-drinkers. This survey also finds that those who drink 15 grams of alcohol a day, which is the equivalent to a glass of wine, shot of a spirit or pint of beer, were almost 30% less likely to become overweight or obese. The most positive association was found with red wine, followed by white. A beneficial effect was also apparent at 30 grams a day, but no longer apparent at 40 grams a day.

From a glycemic load point of view I'd be cautious about the pint of beer since this represents 20 GLs - the ideal daily amount for maximum weight gain being 45GLs and 60 GLs for maintenance. On my Low GL Diet I allow 5 GLs a day for drinks or desserts, which is the equivalent of half a pint of beer every other day or a low-carb lager every day (or a glass of wine).

Is It Safe to Drink in Pregnancy?

Although heavy maternal drinking is well-proven to have harmful effects on infant development, is there a ‘safe’ amount you can drink during pregnancy? Many authorities recommend abstinence. For example, Derek Bryce-Smith, award-winning Emeritus Professor of Chemistry at the University of Reading, believes it is “absurd to think there is a safe cut-off level”. Alcohol, he says, is a powerful anti-nutrient and neurotoxin. Animal studies show that even a dilute solution of alcohol, given around or immediately after mating, can cause chromosomal abnormalities. Alcohol consumption also increases the risk of miscarriage and depresses levels of sex hormones. Dr Bryce-Smith concludes that: “Alcohol consumption is particularly ill-advised around the time of meiosis, two days on either side of ovulation and conception, in men and women.”

Does Drinking Make You Smart or Stupid?

Within minutes of consuming alcohol, it starts to loosen you up, lower your inhibitions and put you in a cheery and gregarious mood. This is due to the release of dopamine, which stimulates you; followed by endorphins, which make you feel high; and then gamma-aminobutyric acid, which makes you relax. The alcohol also gives your blood sugar a boost. Sounds good, doesn’t it? It feels good too, and that’s why we do it. This pleasant effect usually lasts for an hour or so. Several drinks later, however, you (or others) might notice you’re feeling irritable, depressed or even hostile. Needless to say, mental alertness and intellectual performance take a turn downhill. But what are the long-term effects? People who consume high levels of alcohol have reduced intellectual performance on testing, although moderate drinkers do not show the same results. In fact, a study by the National Institute for Public Health in the Netherlands found less risk of poor cognitive function among those who had one or two drinks a day, compared to abstainers. While it is well known that excessive alcohol can lead to dementia, this is not the same thing as Alzheimer’s disease.

Researchers at the University of Pittsburgh psychiatry department in Pennsylvania compared the performance of alcoholics with dementia versus non-alcoholics with dementia. They found a very different pattern of poor mental function, suggesting that alcohol per se wasn’t causing the same kind of brain damage as seen in Alzheimer’s. This finding has been further confirmed by a recent study in which older people, from teetotallers to heavy drinkers, were given MRI scans to see whether there was a link between Alzheimer’s-like damage in the brain and drinking. The researchers, from Rotterdam’s Erasmus Medical Centre, took MRI scans of 1074 people, aged 60 to 90, who did not have dementia. They were categorised according to their alcohol consumption from abstainers to very light (1 drink/week), light (1 drink/week to <1 drink/day), moderate (1 drink/day to <4 drinks/day), to heavy (4 drinks/day) drinkers. The team looked for damage or evidence of stroke, and also measured hippocampus size, which is a strong indicator of Alzheimer’s.

They found that the people with the healthiest brains – meaning the least damage, the least evidence of strokes and the least hippocampal shrinking – were not the very light drinkers or abstainers, but the light or moderate drinkers. Although the heavy drinkers came out worse, this finding suggests that while large amounts of alcohol damage the brain, a glass or two of wine a day does not, and may even reduce your risk of a stroke.

The evidence that a small amount of alcohol may even be brain-protective isn’t based on one study alone. Studies in France have consistently shown that light to moderate alcohol drinkers have a lower incidence of both dementia and strokes, while heavy drinkers increase their risk of both diseases. One recent meta-analysis of 15 studies concludes that "alcohol drinkers in late life have reduced risk of dementia," with a light to moderate drinker having about a quarter of the risk.

Sobering Statistics for Hangovers

The main downside that curbs our alcohol consumption is the hangover! You may also have forgotten much of what happened the night before, a phenomenon known as a blackout. This can be a serious problem if you’ve really abandoned your inhibitions. You may wonder whether the good time was worth it.

Hangover-induced absenteeism accounts for up to 14 million lost working days a year in Britain. Researchers found that people with hangovers posed a danger to themselves and others long after their blood alcohol levels had returned to normal, suggesting that hangovers could be more insidious than actual inebriation.

Longevity

There’s an old saying that if you don’t drink and smoke, you don’t actually live longer, it just feels like it. While there is no doubt that smoking and excessive drinking increase mortality rates, the evidence is not so decisive on moderate alcohol consumption. Among record holders for longevity, many have been abstainers. But the two world record holders have both been regular consumers of small amounts of alcohol. Izumi, the Japanese fisherman who died at 120, liked his sake. And Madam Jeanne Calmant, who died last year at 122, used to enjoy her two daily glasses of port. One interpretation is that these are two isolated cases of people with strong genetic constitution. Another theory is that a small amount of alcohol has a protective effect – perhaps from heart disease, or as a relaxant from taking life too seriously. 

The Bottom Line

For my money, there’s a big difference between occasional drinking, and drinking two or more units every day. I see many clients who have a mild dependency on even such small daily intakes. If a break for a couple of weeks would pose no problem to you, then that indicates a healthy relationship with alcohol. 

Once you start to get drunk from alcohol, then you’ve exceeded your body’s ability to detoxify. If, in addition, you already have increased gut permeability and perhaps an allergy to something in the drink, you’re letting your body in for some punishment and may suffer the cumulative ill effects on your health. 

On the other hand, if you are optimally nourished and have a healthy liver and digestive system, a glass of (preferably organic) wine or beer one to three times a week is unlikely to impact your health.

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