Alcohol

Summary (as seen on HEC.iTV):

If you drink alcohol, having one standard drink per day for women and two standard drinks per day for men may be good for your heart and may help lower blood glucose levels, which is of interest to people with diabetes. More than this amount and you increase your chance of developing high blood pressure, stroke and cancer. Binge drinking the recommended daily amount, say over the weekend, is not advisable as this can dramatically increase blood pressure and risk of having a stroke. A standard drink is for example 285ml of beer or 100ml of wine. It is also recommended that we have 2 alcohol-free days per week. If you don't normally drink alcohol, you don't need to, even if you have heart disease or conditions which increase your risk of developing heart disease. This is because benefits of alcohol can be obtained in other ways through plant foods, grape products and through enjoying food and company in other ways.
See also the HEC healthy eating pyramid.

How much alcohol is recommended?

Since many adverse effects of alcohol consumption exist, a moderate alcohol intake should be considered optional rather than an essential component of a healthy diet. It is not recommended to consume in excess of 2 standard drinks per day; one standard drink has 10g of alcohol which includes: 285ml full strength beer or 375 light beer or 100ml wine or 60ml sherry or 30ml spirit.

To convert % alcohol to grams, convert % volume to ml of alcohol in drink and multiply by 0.8, since 1ml of alcohol weighs only 0.8g e.g. 375 ml beer 4.8% alcohol is 4.8% of 375 = 18ml alcohol x 0.8 = 14.4g alcohol.

Light drinking = <20g/day i.e. < 2 standard drinks/day

Moderate = 20-40g/day

High = >40g/day on individual occasions

Heavy/excessive = >40g/day regularly for extended periods

Light to moderate drinking is considered to be low risk drinking, as long as there are 2 alcohol-free days a week. You cannot save daily drinks for one occasion. Binge drinking is particularly harmful and can result in significantly elevated blood pressure and death in some cases i.e. 6 drinks for men and 4 drinks for women in a row.

Alcohol contributes to obesity through its high energy content and by lessening the body’s ability to burn fat. Fat storage is promoted, particularly in the belly.

Alcohol and health

The relationship between alcohol and mortality is a J-shaped curve (Boffetta & Garfinkel Epidemiol 1990; 1: 342-8). At light intakes (1-2 standard drinks/day or 10-20g/day) alcohol is protective and the protection is strongest for heart disease. This level of intake can reduce the risk of heart disease by 20-60% and death from all causes by 10-20%. This association has also been found with diabetics (J Am Med Assoc 1999; 282: 239-246) with the largest benefits from moderate alcohol intake being observed in those at highest risk of heart disease. As diabetes is a risk factor for heart disease, this finding could help improve the life span, as well as quality of life for those suffering from diabetes. However, once intake rises above 2 standard drinks/day, so does mortality from cancer, accidents, all causes and heart disease. Excessive drinking can also destroy the insulin producing cells in the pancreas and result in diabetes.

There is evidence that the chronic intake of more than 30g alcohol per day may result in hypertension and that certain individuals are particularly susceptible. Drinking alcohol regularly in excess of the recommended (1-2 standard drinks per day) can lead to weight gain, increased blood pressure and triglyceride levels, which are all risk factors for heart disease. 1-2 drinks per day may be protective against heart disease, but quantities above this are not beneficial. There are some indications that moderate drinking may reduce the risk of ischaemic stroke whereas heavy drinking may increase the risk of haemorrhagic stroke.

Notwithstanding the adverse effects on blood pressure in some people, many scientific studies have associated moderate alcohol intake with a significant reduction in the overall risk of coronary heart disease (CHD). This applies to both sexes at all ages, but is most evident in men over 50, where CHD risk is highest. In a 12 year follow-up of 85,000 women (Fuchs et al. NEJM 1995; 332: 1245-50), 1-3 drinks/week offered the greatest benefits from alcohol, especially women aged 50 and over with one or more coronary risk factors (e.g. hypertension, diabetes, smoking etc). At this level, the chances of dying were lower than in women who drink less or more, largely due to protection against heart attacks and strokes. Younger women with coronary risk factors also benefited – but less than the 50 plus women.

Most of the earlier studies did not separate wine from beer or spirits, but two recent studies have shown that wine offered a 30% to 50% higher protective effect of heart disease than beer or spirits (Gronbaek et al., Br Med J 1995; 310: 1165-9). One study followed over 7000 men and 5000 women for 10-12 years. It found that people who drank 3-5 glasses of wine per day had half the risk of CHD and stroke compared to those who never drank. However, only ONE glass a day was sufficient to produce this effect. Beer drinkers lowered their risk by 30% while spirits showed only a slight trend towards lowered risk.

However, another study in 1997 (Am J Cardiology 1997; 80: 416-20) studied 5498 lifelong teetotallers, 4194 ex-drinkers and 81,825 who reported drinking more than once a month in the previous year. Increased alcohol intake reduced the risk of being admitted to hospital with heart problems such as acute myocardial infarct, CHD, angina or chronic ischaemic heart disease. All types of alcoholic beverages appeared to protect against CHD and that additional protection by specific beverages appeared minor.

Possible mechanisms could be through its effect on raising HDL, reducing platelet aggregation and preventing oxidation of LDL (contains antioxidant phytochemicals). It is well-known that alcohol raises HDL, but this explains at best only 50% of the protection afforded by wine, pointing to more broadly-acting factors. The phenolic compounds in wine (e.g. flavonoids) can act as antioxidants, reduce angiogenesis, reduce thrombosis and inflammatory reactions and reduce platelet aggregation.

A 5 year follow-up study (Kiechl et al. BMJ 1996; 313: 1040-44) on 800 men and women aged 40-79 compared insulin levels with alcohol intake and found that people with low or moderate alcohol consumption had lower than average levels of insulin, less insulin resistance, higher levels of HDL and lower levels of blood clotting factors. However, the effect of alcohol on insulin levels was reduced in the overweight/obese subjects.

Wine has been implicated as being one of the factors responsible for the lower incidence of CHD among Mediterranean populations, who consume on average about 6% of total energy from ethanol, of which 94% is obtained from wine.

However, recent evidence from the Lyon Diet Heart Study indicates that the antiplatelet effect of wine ethanol differs according to the dietary pattern and intake of saturated fat, which suggests that specific food patterns may influence the effect of wine ethanol on platelets.  In the French men with established CHD, consuming wine with a Mediterranean diet low in saturated fat (8% energy intake) had no effect on platelets.  In French men consuming wine with a prudent Western diet higher in saturated fat (12% energy intake) there was an inverse relationship between ethanol and platelet aggregation (de Lorgeril. The Lancet 1999; 353: 1067).  In other words, wine may be more beneficial to people consuming higher intakes of saturated fats.

Excess alcohol (over 3 drinks a day) increases the risk of the common cancers (breast, colon, rectum) and some of the rarer cancers (oral, oesophagus, larynx and stomach). For the latter, the risk increases in a dose-related manner, and smoking in combination with alcohol intake significantly increases the risk. In the absence of smoking the risk of these rarer forms of cancer is small. For women, the risk of breast cancer increases by 20% when consuming only 2 drinks a day relative to abstainers. This needs to be weighed up against the protection against heart disease. Alcohol itself is not a carcinogen, but in animal experiments it may enhance the carcinogenic process without itself having an initiating capability. It thus acts as a co-carcinogen.

Take Home Messages

1.   Alcohol is a double-edged sword. At light intakes (1-2 drinks/day) it protects against coronary heart disease and stroke. At intakes >2 drinks/day, it has adverse effects on blood pressure, increases the risk of haemorrhagic stroke and increases the likelihood of cancer.

2.  Light to moderate consumption is now urged – less is best. This means only ONE standard drink a day for women and TWO for men, and none during pregnancy. This is lower than the NH&MRC recommendations of 2 for women and 4 for men.

3.  Binge drinking is harmful and is related to arrhythmia, elevated blood pressure and to platelet-rebound effect after alcohol withdrawal.

Last Updated: July, 2002