Alcohol Metabolism and Blood Glucose

Drinking with diabetes. It’s one of the most common questions I get from friends and colleagues. The answer I give is not usually what people expect. My previous post on this topic “A Brief Guide to Alcohol Metabolism and Blood Glucose” is one of my most visited posts, and so I thought I’d revisit the topic of alcohol metabolism and blood glucose with a tad more detail.

If you’re still confused after reading this post or want to know more, check out the peer reviewed sources I have linked at the end of the page.

Alcohol is not a Carbohydrate

Many people seem to lump alcohol in with carbohydrates. They expect alcohol itself to act as sugar and raise blood glucose levels.  Although many alcoholic beverages contain carbohydrates, which may raise blood glucose levels, alcohol itself is not a carbohydrate.  During the fermentation process involved in production of alcohol, yeast use sugar and produce ethyl alcohol (ethanol) and CO2, neither of which is a carbohydrate and therefore neither is metabolized by the body as a carbohydrate.

Takeaway: Your body doesn’t recognize the actual alcohol in your drink as carbohydrates, so it is absorbed into the body differently (via passive diffusion), transported to different locations, and metabolized (broken down) via very different pathways than carbohydrates are.

How then is Alcohol broken down?

Alcohol primarily gets broken down in the liver (although some of it may be metabolized in the stomach- known as first-pass metabolism).  Our bodies cannot store alcohol in its original form (like it can other nutrients), so it works very hard to rid itself of both the ethanol and the toxic intermediate of alcohol metabolism, acetaldehyde. There a number of pathways (at least 3 that we are aware of), but the primary pathway involves  the two enzymes alcohol dehydrogenase and acetaldehyde dehydrogenase. 

Alcohol breakdown takes priority over the breakdown of carbohydrates, protein, and fat. Liver cells detoxify alcohol, and one of the end products acetate may be converted to Acetyl CoA and used to synthesize fatty acids, which are then assembled into fats for storage and/or utilization.

Alcohol and Blood Sugar

The effect of alcohol on blood sugar is a little more complicated.

We’ve learned that alcohol differs from carbohydrates and so does not in itself cause blood glucose to spike.  We’ve also mentioned that alcohol breakdown takes priority over the breakdown of other nutrients.  Another thing to add is that heavy drinking suppresses gluconeogenesis (GNG), which is the body’s process of synthesizing glucose in the liver to maintain blood glucose levels and avoid  dangerous hypoglycemia. The steps in the primary alcohol metabolism pathway produce two NADH molecules. This results in a decrease in the NAD+/NADH ratio, which can inhibit the production of pyruvate from lactate (a substrate for gluconeogenesis) and may lead to accumulation of lactate.

This means that people with diabetes should be wary, as blood sugar levels may fall depending largely on the type of alcoholic beverage consumed, activity level, and when food was last consumed. It can become difficult to raise your blood sugar as you ingest more alcohol.  Because your body focuses on breaking down alcohol over other nutrients, you may be more likely to become hypoglycemic if you drink on an empty stomach or post workout.

This is not to say that consuming an alcoholic beverage will always result in lower blood sugars. Hyperglycemia (High blood sugar) may also be a risk, as many alcoholic drinks contain carbohydrates that you may need to account for.

Typical Drinks and their Carbohydrate content

General Tips to Safe Drinking for the Type 1 Diabetic

That being said, there are a few ways to drink responsibly as a diabetic, and minimize the risks associated with alcoholic consumption.

  1. Make sure to check blood sugar before beginning to drink
  2. Don’t drink on an empty stomach
  3. Never drink alcohol when your blood sugar is low
  4. Always carry glucose
  5. Always know what it is you are drinking
  6. Drink in moderation
  7. Don’t drink pre or during a workout
  8. Inform friends that you have diabetes

What if you’re not Diabetic? Is hypoglycemia still a risk?

Although extremely rare, hypoglycemia may still be a risk, even if you are not living with diabetes.  It is possible for people without diabetes to become hypoglycemic if they drink excessively without having eaten for days or if they were to conduct extreme exercise under the influence.

Generally the advice is the same: be smart, be safe, and enjoy that IPA

For More on Alcohol Metabolism and Blood Glucose:

Cederbaum AI. Alcohol metabolism. Clin Liver Dis. 2012;16(4):667-85.

Søren Plougmann, Ole Hejlesen, Benjamin Turner, David Kerr, David Cavan,
The effect of alcohol on blood glucose in Type 1 diabetes—metabolic modelling and integration in a decision support system,
International Journal of Medical Informatics, Volume 70, Issues 2–3, 2003,

Steiner JL, Crowell KT, Lang CH. Impact of Alcohol on Glycemic Control and Insulin Action. Biomolecules. 2015;5(4):2223-46. Published 2015 Sep 29. doi:10.3390/biom5042223

Tetzschner R, Nørgaard K, Ranjan A. Effects of alcohol on plasma glucose and prevention of alcohol‐induced hypoglycemia in type 1 diabetes—A systematic review with GRADE. Diabetes Metab Res Rev. 2018;34:e2965. https://doi.org/10.1002/dmrr.2965

Short- and medium-term effects of light to moderate alcohol intake on glycaemic control in diabetes mellitus: a systematic review and meta-analysis of randomized trials.J. A. Hirst, J. K. Aronson, B. G. Feakins, C. Ma, A. J. Farmer, R. J. StevensDiabet Med. 2016 Sep 2 Published online 2016 Sep 2. doi: 10.1111/dme.13259

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