Alcohol

Contents

• Recommended amounts
• What is a unit of alcohol?
• The effect of alcohol on blood glucose
• Ways to prevent alcohol-related hypoglycaemia
• Watching your weight
• Useful resources

Recommended amounts 

Having diabetes does not mean that you need to completely avoid drinking alcohol. In fact, government guidelines for sensible drinking are the same whether you have diabetes or not.

• Men and women are advised not to regularly drink more than 14 units of alcohol a week.
• Pregnant women are advised that no level of alcohol intake is safe in pregnancy.
• If you drink as much as 14 units a week, it is advisable to spread this over three or more days. If you have one or two heavy drinking sessions each week, this can increase the risks to your health. 

The following drinks all have 14 units of alcohol:

• 6 pints of lager (4% ABV)

• 6 medium glasses of red wine (13% ABV)

• 14 single shots of spirits (40% ABV) such as rum, whisky or vodka

The risk of developing a range of illnesses, including high blood pressure and certain cancers, increases if you consistently drink more alcohol than the recommended amounts.

What is a unit of alcohol? 

As alcoholic drinks come in different strengths and sizes, units are a good way to tell how strong your drink is.

One unit of alcohol is 10 ml or 8 g of pure alcohol. One unit is equal to the following:

• One single pub measure (25 ml) of spirits (40% ABV)
• One half-pint of normal-strength lager, beer or cider (3.5% ABV)
• One small glass (100 ml) of wine (10% ABV)
• One glass (50 ml) of liqueur, sherry or other fortified wine (20% ABV) 

Table 1 below shows how many units of alcohol there are in some common drinks.

In recent years, the alcohol content of some drinks has increased, with many wines and beers now stronger than they once were. So remember that a drink may be stronger than you think. Remember too that many measures, particularly home measures, are larger than standard sizes.

A more accurate way of calculating units is by the percentage of alcohol by volume (ABV). This is the percentage of alcohol in one litre of the drink.

For example:

• A wine of 14% ABV has 14 units in a litre.
• If you drink 125 ml you have had 1.75 units.
• If you drink 250 ml you have had 3.5 units.

The effect of alcohol on blood glucose

Alcohol can both increase and decrease blood glucose levels. If you have a drink that contains carbohydrate, such as real ale, cider, alcopops, a liqueur or a dessert wine, it is likely that you will initially notice an increase in your blood glucose level.

If, however, you have a drink that does not contain carbohydrates, such as a gin and diet tonic, a vodka and diet Coke or a glass of red wine, you may not see any change in your blood glucose level.

Alcohol: risk of hypoglycameia

When alcohol is processed in the liver, it can contribute to a drop in blood glucose levels. This is because alcohol interferes with the normal release of stored glucose from the liver, and so blood glucose levels can fall, even if you eat extra carbohydrate.

For people with type 1 diabetes, this could result in low blood glucose, causing a hypoglycaemic episode (a ‘hypo’). The risk of hypoglycaemia can persist for a number of hours after drinking particularly if large amounts of alcohol have been consumed. 

If you are concerned about the impact of alcohol on your blood glucose, speak with your diabetes care team who will be able to give you advice based on your personal circumstances. 

Ways to prevent alcohol-related hypoglycaemia 

There are a few general rules to help prevent hypos when you are drinking alcohol:

• Avoid drinking on an empty stomach.
• Eat regular carbohydrate-based snacks while you are drinking alcohol and before you go to bed.
• Monitor your blood glucose levels closely.
• Always have your hypo treatment with you and make sure you keep it next to your bed.
• Make sure that the people you are with know that you have diabetes and how alcohol affects your blood glucose
• Stick to the recommended daily units of alcohol.
• Alternate alcoholic drinks with sparkling water, sugar-free lime and soda, or diet drinks.

Watching your weight 

Alcohol contains 7 calories per gram. These calories usually offer no nutritional value. If you are concerned about your weight, keep the following points in mind:

• Home measures tend to be more generous.
• Check that all mixers and soft drinks are sugar-free or diet varieties.
• Drink ordinary-strength beers, lagers and ciders. Low-alcohol varieties can be higher in sugar and low-sugar versions can be higher in alcohol.
• Alcoholic drinks with high sugar content, e.g. sweet sherry, dessert wines, liqueurs and alcopops, should be drunk only occasionally.

Look at Table 1 below to see the alcohol and calorie content of some common drinks. 

Table 1: Alcohol and calorie content of common drinks

Note: Calories do not equal carbohydrates!

Regularly drinking more than is recommended can increase the risk of serious health problems including certain cancers, liver disease, stroke, high blood pressure and mental health disorders.

Useful resources

For more information on how drinking alcohol can affect your diabetes, click here. 

Drinkaware is an independent charity that has useful information on its website.

All images used are courtesy of Carbs & Cals.