Wine, wisdom and diabetes

'Drink moderately, for drunkenness neither keeps a secret nor observes a promise.' Cervantes, Don Quixote. This wise advice from the 17th century reinforces modern health messages on alcohol. For those of us who choose to drink, it is useful to be aware of both the risks and the benefits of drinking alcohol.

It is easy to overestimate a standard drink - most wine glasses can hold almost two standard glasses when full.

How much alcohol should people with diabetes drink?

A maximum of two standard drinks per day (14 drinks per week) for women
A maximum of three standard drinks per day (21 drinks per week) for men.

The limits for women are lower than for men due to several differences in body function.

What is a standard drink?

300 mls of standard beer
600 mls of reduced alcohol beer
100 mls of wine
30 mls (one pub measure) of spirits
70 mls of fortified wine (sherry, port)

It is very easy to overestimate a standard drink. Most wine glasses can hold almost two standard drinks when full. A 750ml bottle of wine provides approximately 7.5 standard drinks. A litre jug of beer holds slightly more than three standard drinks.

Alcohol – the 'empty calorie'

Alcohol is a poor source of almost all nutrients except energy. Heavy drinking actually causes extra losses of some nutrients in the urine. This explains why heavy drinkers who substitute alcohol for healthy food are prone to nutritional deficiencies.

If you choose to drink but also need to lose weight, consider those extra calories. It would be wise to limit alcohol to weekends or special occasions, rather than the more liberal guidelines given above.

Sugar content

In the past, people with diabetes have been advised to avoid alcoholic beverages containing sugar, including beer. The sugar content of beer per 100mls is quite low, but the amount of sugar and energy can soon add up if beer is consumed as one-litre jugs.

The carbohydrate content (which includes remaining barley starch products and sugar) of some brands of beer may be higher than others. But without nutritional labelling, the consumer has no way of knowing.

While a small amount of sugar can be included in the diet of people with diabetes, very sweet drinks such as sweet liqueurs are likely to be rapidly absorbed and are probably best avoided or consumed in very small quantities.

Risks and benefits

For many people drinking alcohol is a normal part of social events and celebrations. Although most people with diabetes can enjoy a moderate amount of alcohol, it is important to understand the risks as well as the benefits.

Alcohol can have both blood glucose lowering and glucose raising effects depending on how much is consumed, whether or not food is eaten at the same time, and whether or not alcohol is drunk on a daily basis.

Alcohol can have additional blood glucose lowering effects in those who take insulin or some types of diabetes tablets.

The good news about alcohol

Drinking a moderate amount of alcohol with meals or snacks has no immediate effect on blood sugar levels in most people with Type 1 or Type 2 diabetes.

There is also convincing evidence that 1-2 standard drinks per day will reduce the risk of heart attack and stroke. Some studies have suggested that red wine may be more protective than other alcoholic drinks due to its antioxidant content, but this remains to be proven.

The bad news about alcohol

Excessive daily drinking (4.5 standard drinks) has been shown to cause a rise in blood glucose levels in people with Type 2 diabetes. This is because excess alcohol interferes with the action of insulin.

Excessive long term drinking can also raise blood pressure.

Alcohol and hypoglycaemia

If you take insulin or tablets, it's best to discuss alcohol use with your doctor or diabetes nurse educator. Alcohol can prevent the liver from making new glucose for many hours after drinking, which increases the risk of alcohol related hypoglycaemia, particularly for people taking medication.

This can be dangerous because some signs of drinking too much, such as confusion or slurred speech, are similar to those of a low blood glucose level. Other people may not help you because they think you are drunk, and if you have been drinking, you may find hypoglycaemia more difficult to recognise. Treatment may then be delayed.

Alcohol can also affect your body's ability to recover from hypoglycaemia and you may need to treat a low blood glucose reading more than once.

Key points for safe drinking

Never drink on an empty stomach – drink with a meal or snack containing carbohydrates
Keep to the recommended limits for safe drinking
Know your own limits
Don't drink after exercise, particularly if you take insulin or tablets
Check your blood sugar before you go to sleep to see if it is falling, as alcohol can cause delayed hypoglycaemia during the night
Eat a carbohydrate snack before going to bed, for example, a wholegrain sandwich.

See more on food to serve with alcohol ...

Wise drink choices

Select drinks that are lower in alcohol and sugar, for example:

Mix a single nip of spirits with sugar free drinks such as diet soft drinks, soda water or sparkling mineral water, rather than choosing 'ready to drink' pre-mixed spirits of unknown sugar content
Choose lower alcohol beers or try a shandy (beer and diet lemonade)
Wine and sherry drinkers: choose quality over quantity and avoid the sweet stickies - red or dry white wines are good choices
Non-connoisseurs can make cheaper wine last longer by making a spritzer (mix wine with soda water or sparkling mineral water)
Liqueurs are best avoided as they are high in both sugar and alcohol content.

It also helps to 'sip and savour', and to drink water or non-alcoholic beverages between glasses of alcohol.

Wendy Grylls is a clinical and community dietitian. In association with the Department of Human Nutrition, University of Otago, Wendy completed a doctoral thesis which investigated the relationship between lifestyle factors and blood glucose control in older adults with diabetes.

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