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HealthInfo Waitaha Canterbury

Alcohol & diabetes

If you take insulin or certain diabetes tablets, alcohol can cause low blood glucose (sugar) levels 8 to 10 hours after you have stopped drinking.

The effects of drinking alcohol when you have diabetes

Your liver does all kinds of things for your body. Most importantly in relation to alcohol, it is a blood filter. It removes toxins like alcohol from your blood.

But your liver only does one thing at a time. When your body is dealing with alcohol, the effect of insulin can be delayed. It takes hours for your liver to clear an alcohol binge. For all that time, the insulin stays in your system.

When you have been drinking, your body responds more sluggishly to the treatment of low blood glucose. Alcohol also stops your liver from making glucose if your glucose level is low.

As well as this, alcohol reduces your awareness of having low blood glucose levels and prevents glucagon from working properly.

So, be aware that you may not be aware.

Keeping safe when drinking alcohol

It is OK to say NO!

Standard drinks

A standard drink is smaller than many people expect. In New Zealand, it is a drink that contains 10 grams of pure alcohol. Drinks poured at home or in a bar tend to be more than one standard drink.

A 1,125ml bottle of spirits contains about 34 standard drinks.

Low-risk drinking

Low-risk drinking is considered to be no more than:

This is shown in the following graphic from Te Hiringa Hauora Health Promotion Agency.

You can usually have 2 to 3 standard drinks before it starts to affect your diabetes.

It takes about 1 hour for your body to process and clear one standard drink.

Pre-mixed drinks and standard mixers will make you go high initially but they will not stop you going low.

Note. The current low-risk drinking advice was developed in 2011. A review of the low-risk drinking advice for Aotearoa New Zealand has been commissioned. In the meantime, the following are more recent guidelines from other jurisdictions: Canada's Guidance on Alcohol and Health (updated in 2023) and Australian Alcohol Guidelines revised (updated in 2020).

Getting help for alcohol problems

If you think you have an alcohol problem, contact one of the following services for help:

Written by Christchurch Diabetes Centre. Adapted by HealthInfo clinical advisers. Last reviewed November 2022.


Page reference: 933004

Review key: HIDIA-21832