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How Alcohol Affects Blood Sugar

Brooke Marsal, MS, RD
December 29, 2020

Whether you are newly diagnosed with diabetes or a veteran at diabetes management, it’s important to understand how alcohol affects your blood sugar. This article provides you with an overview of what happens in the body when you drink alcohol, how alcohol affects blood sugar levels, and what you can do to make sure you are able to enjoy a drink or two without compromising your health. 

What Happens When You Drink

Alcohol is absorbed very quickly and easily through the small intestines. Once absorbed, alcohol travels through the blood to the liver where it is broken down and turned primarily into water (which is eliminated through the urine), carbon dioxide (which is eliminated through the lungs), and fat (which is stored either in the liver or in other areas throughout the body).

Effects on Blood Sugar

Hypoglycemia (Low Blood Sugar)

Because alcohol is toxic, when you drink, almost all of the liver’s attention goes towards breaking down the alcohol. As a result, the liver is unable to release stored glucose into the blood, a process which is necessary to maintain blood sugar levels in between meals. This means that drinking puts you at risk of hypoglycemia (low blood sugar).

Taking insulin or diabetes medications, such as glyburide, glimepiride, or glipizide, can further contribute to low blood sugar because they increase the amount of insulin your body produces. If you are taking these medications or insulin, you are at even greater risk of hypoglycemia because insulin’s job is to lower blood sugar. If the liver can’t balance out the effects of insulin and you aren’t eating carbohydrates that raise your blood sugar again, you may find yourself becoming hypoglycemic.

Hyperglycemia (High Blood Sugar)

Alcohol can also potentially raise blood sugar levels. Many alcoholic drinks such as beer, wine, and cocktails all contain enough carbohydrates to raise blood sugar levels. The consumption of alcohol also increases appetite and decreases self-control. This means you are more likely to eat large quantities of high carb foods while drinking, which could lead to high blood sugar.  

How to Drink Safely

Preventing Low Blood Sugar

  • Drink slowly, and have no more than 1 drink per hour.
  • Ideally, do not drink more than the recommended daily limit: 2 drinks/ night for men, 1 drink/ night for women (1 drink = 12 ounces beer OR 5 ounces wine OR 1½ ounces of distilled spirits such as rum, whiskey, gin, etc.).
  • Never drink on an empty stomach. Always consume alcohol with a meal or snack containing carbohydrates.
  • Check your blood sugar more frequently throughout the night and before go to bed.
  • If you blood sugar is below 100 mg/dL before bed, have a bedtime snack.
  • Become familiar with the symptoms of low blood sugar (see below).
  • Have glucose tablets and glucagon readily available in case of a hypoglycemic emergency.(Note that glucagon may not work as effectively after the consumption of alcohol since glucagon signals for the liver to release stored glucose, but after drinking the liver isn’t as capable of performing this function).
  • Always wear a medical alert piece of jewelry that indicates you have diabetes.

Symptoms of Low Blood Sugar

  • Confusion
  • Sleepiness
  • Blurred vision
  • Headaches
  • Lightheadedness or dizziness
  • Lack of coordination
  • Headaches
  • Unconsciousness

How to Treat Low Blood Sugar: Follow the 15-15 Rule

  1. Consume 15 grams of glucose or simple carbohydrates (e.g. glucose tablets OR 4 oz juice/regular soda OR 1 tbsp of sugar/honey/corn syrup, etc.)
  2. Recheck your blood sugar after 15 minutes
  3. If blood sugar levels are still <70 mg/dL, repeat the steps above
  4. Once blood sugar returns to normal, eat a small snack such as half of a sandwich if your next planned meal or snack is more than an hour or two away
  5. If someone you know with diabetes has passed out while drinking and you suspect it’s from low blood sugar, give them a glucagon shot and call 911

*NOTE: the symptoms of low blood sugar can be easily mistaken for symptoms of alcohol intoxication.

Prevent High Blood Sugar

  • Avoid sugary and mixed drinks
  • Choose dry wines over sweet wines
  • Choose light beers
  • Have healthy foods options available to snack on
  • Do no drink more than the recommended daily limit: 2 drinks/night for men, 1 drink/night for women
  • Drink water throughout the night

Feel free to send a message to your dietitian through iHealth Unified Care App if you have any question!