Abstract
Although fewer individuals with type 1 diabetes mellitus (T1DM) drink alcohol, the potential and severity of harm associated with its consumption is higher in persons with diabetes. Alcohol use affects glucose metabolism and results in various potential adverse effects both from acute ingestion and chronic ingestion in persons with T1DM. The purpose of this article is to describe the effects of alcohol on glucose metabolism and diabetes control in persons with T1DM and propose counseling pearls for providers working with patients in this population.
‘. . . it is important for providers to discuss the effects of alcohol on diabetes and develop strategies to maintain good control and minimize associated risks . . .’
While alcohol use tends to be lower in patients with type 1 diabetes mellitus (T1DM) than in the age-matched general population, rates of drinking in young adults with T1DM range from 19.3% to 26% in the literature.1-3 Although fewer individuals with T1DM drink alcohol, the potential and severity of harm associated with its consumption is higher in persons with diabetes. Early adulthood is a time of new environments, increased independence, and experimentation. It is also a time where there may be increased access to alcohol, less parental monitoring, and an increased propensity for risky behavior. 4 Because of the prevalence of alcohol consumption in this population and the potential risks associated with its use, it is important for providers to discuss the effects of alcohol on diabetes and develop strategies to maintain good control and minimize associated risks for those young adults who choose to consume it. The purpose of this article is to describe the effects of alcohol on glucose metabolism and diabetes control in persons with T1DM and propose counseling pearls for providers working with patients in this population.
Effects of Alcohol on Glucose Metabolism
Eighty percent of ingested alcohol is metabolized in the liver, leading to an increase in the NADH:NAD ratio (NAD is nicotinamide adenine dinucleotide and NADH is its reduced form). 5 This so-called “redox shift” results in inhibition of gluconeogenesis. After the consumption of 48 g of alcohol (approximately 4 glasses), hepatic gluconeogenesis has been shown to decrease by about 45%. 6 Gluconeogenesis is required to maintain glucose levels in the fasting state and inhibition of gluconeogenesis may result in hypoglycemia.
Glycogenolysis is also impaired by alcohol. 7 In a patient with normal glycogen stores, hepatic glucose output has been shown to reduce by 12% after ingestion of a moderate amount of alcohol. 7 This rarely causes hypoglycemia. However, if glycogen stores are depleted (as in malnourished individuals, alcoholics, and potentially persons consuming very low carbohydrate diets or people who are fasting or drinking without consuming food), hepatic glucose production may be significantly impaired by alcohol ingestion and can lead to potentially life-threatening hypoglycemia, especially in patients with T1DM.
Short-Term Effects of Alcohol in Diabetes
Moderate amounts of alcohol (1 g/kg), when consumed with a meal, appear to have limited effects on blood glucose and insulin levels in patients with T1DM.
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However, when alcohol is consumed in a fasted state or several hours after a meal, lower blood glucose levels have been observed. Lange et al
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compared blood glucose levels and incident hypoglycemia in 23 males with type 1 diabetes following administration of alcohol or mineral water.
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Consumption of just 1 L of beer several hours after an evening meal resulted in significantly lower blood glucose levels and more episodes of hypoglycemia compared with consumption of mineral water. Interestingly, this finding was significant between the hours of 7
Analysis of registry data from more than 30 000 young adults with T1DM found higher alcohol use to be associated with higher rates of severe hypoglycemia (event requiring assistance of another person to actively administer carbohydrate, glucagon, or other resuscitative actions) and diabetic ketoacidosis (DKA).
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The registry classified participants as abstainers, low-risk drinkers (≤1 serving of alcohol per day for women and ≤2 servings per day for men) and at-risk drinkers (>1 serving per day for women and >2 servings per day for men). The rates of severe hypoglycemia were similar between low-risk and at-risk drinkers, but were significantly higher in those consuming alcohol than for those who abstain from alcohol. At-risk drinkers experienced DKA at a rate of 18.9 episodes per 100 patient years compared with just 6.4 episodes per 100 patient years for those abstaining from alcohol and 7.5 episodes per 100 patient years for those consuming moderate amounts of alcohol (
A study by Kerr et al 11 found that liberal intake of alcohol (approximately 4-5 drinks) is associated with increased lactate and β-hydroxybutyrate levels in patients with T1DM. Accumulation of β-hydroxybutyrate causes ketosis and may result in nausea, vomiting, impaired mental function and potentially coma or death. The study found a rise in ketones despite uninterrupted insulin administration in a controlled setting. The authors cautioned risk of ketosis may be more severe in less controlled circumstances, especially as many of the symptoms of DKA mimic symptoms of extreme intoxication.
Effects of Chronic Alcohol Consumption on Diabetes Control
Moderate alcohol intake appears to be associated with increased insulin sensitivity in young adults. 12 However, the relationship between alcohol and insulin sensitivity appears to be J-shaped, with increased insulin resistance in both abstainers and in heavy drinkers. 13 Higher alcohol consumption has also been associated with worse glycemic control and poor diabetes self-care.2,14 The same registry analysis that found increased risk of severe hypoglycemia and DKA in at-risk drinkers, found the highest HbA1c levels in this cohort as well, even after adjustment for age, gender, duration of diabetes and mode of therapy. 2 A study by Ahmed et al 14 found that individuals with higher alcohol consumption reported reduced diabetes self-care behaviors, including self-monitoring of blood glucose, HbA1c testing, and adherence to diabetes medications.
Discussion and Conclusions
It appears that moderate alcohol intake when combined with food, is a relatively safe practice for individuals with T1DM. Alcohol consumption without food, should be avoided. While moderate amounts of alcohol have been associated with increased insulin sensitivity, heavy drinking is associated with increased insulin resistance, worse glycemic control, poor diabetes self-care behaviors, increased risk of severe hypoglycemia, and increased risk for DKA. Young adults should be advised to drink alcohol responsibly. This includes avoiding binge drinking and ingesting carbohydrates while consuming alcohol. Patients should be educated that alcohol can reduce the awareness of hypoglycemia and blood sugars should be monitored more closely following alcohol consumption. Patients should also be informed to watch for delayed hypoglycemia and that additional carbohydrate intake or reductions in insulin dose may be necessary to avoid low blood glucose. Patients should be advised to wear identification and inform others of their diagnosis of diabetes and the risk of hypoglycemia and DKA associated with alcohol use. Hypoglycemia may be confused with drunkenness, so additional vigilance may be required by those accompanying an individual with T1DM. Help should always be secured when the status of the individual with T1DM is in question.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.