The Effect of Alcohol on Blood Glucose Levels

Updated February 21, 2017

Alcohol can affect a diabetic's control of blood glucose levels, so it is important that a diabetic drink with caution. When you ingest food, the body turns the food to sugar or glucose. The pancreas produces insulin to help move the glucose into the body's cells for energy use. When insulin is working effectively, blood sugar levels are stable. Alcohol has the ability to lower blood sugar levels. For those who are on insulin, this can be dangerous because the combination of insulin and alcohol can cause hypoglycaemia, low blood sugar. Low blood sugar levels can lead to coma and possible death.

Blood Sugar Levels

An average blood sugar level is 70 to 100 milligrams per decilitre. Diabetics have a larger range, 70 to 120 mg/dl. Stable blood sugar levels are important to maintain a healthy circulatory system, kidney function, responsive nervous system and good eyesight. When blood sugar levels rise or lower, every organ system in the body is affected.


Hypoglycaemia or low blood sugar is when the blood sugar or blood glucose levels drop below 70. Blood sugar levels can drop with few symptoms, but when the levels drop quickly, complications occur. For men, blood sugar levels below 50 mg/dl are dangerous, for women, blood sugar levels below 40 mg/dl are dangerous.


Low blood sugar levels cause shakiness, dizziness, confusion, sweatiness, blurred vision and weakness. If the blood sugar is not raised with juice, soda, sugar or glucose tablets, the diabetic or patient may slip into a coma with possible death.


Alcohol can lower blood sugar levels, so it is important to drink alcohol with meals or a snack. Alcohol remains in the blood longer than the glucose from food, so you can be at risk of hypoglycaemia for several hours after drinking.


If you are on insulin, you are at a higher risk of hypoglycaemia than the diabetic who is not on insulin. If you take oral hypoglycaemic medications, the interaction of the alcohol with the medications may cause nausea, rapid heartbeat and impaired speech. Sweet wines, liqueurs, sweetened mixed drinks, ales and regular beers have high sugar content, which can lead to complications with high glucose levels when consumed on a regular basis. Health care providers, who allow alcohol, will suggest an occasional glass of wine or light beer. If you are taking the medication metformin, do not use alcohol.

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About the Author

Pauline Gill is a retired teacher with more than 25 years of experience teaching English to high school students. She holds a bachelor's degree in language arts and a Master of Education degree. Gill is also an award-winning fiction author.