Alcohol and diabetes: a potentially dangerous mix

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The Question: How does alcohol consumption affect diabetes? I work with street people who don’t always eat properly. Does it worsen their diabetes?

The Answer: Intuitively, you would think that drinking would cause a spike in insulin, given the sugars involved in wine, spirits and other alcoholic beverages. But in fact, alcohol can cause the opposite problem – hypoglycemia or low blood sugar – oftentimes, many hours after a drink has been ingested, making it particularly very risky for those diagnosed with diabetes.

Those with diabetes who imbibe require vigilance in the form of testing blood sugars. In some cases, it can be as simple as remembering to eat before drinking and reducing insulin. In others, it may be that drinking to excess and falling asleep late could trigger a hypoglycemic attack in the form of seizures.

“Alcohol can cause delayed hypoglycemia many hours later,” said Jeremy Gilbert, Sunnybrook endocrinologist. “It’s not necessarily predictable, so that makes it even more challenging. You don’t even know if it’s going to happen.”

More than nine million Canadians has diabetes or a condition called pre-diabetes, which is defined as a person whose blood glucose is higher than normal but not high enough to constitute a case of diabetes. Left unchecked, those with pre-diabetes are at risk of developing type 2 diabetes, according to the Canadian Diabetes Association.

Provincially, more than 1.2-million people in Ontario have diabetes and by 2020, it is projected that number will increase to 1.9 million.

Diabetes can be particularly deleterious to health: it is the number 1 cause of dialysis, blindness and non-traumatic amputations. Eight out of 10 of patients with diabetes will have a cardiovascular event and they have four times the risk of stroke compared to those without the diagnosis.

Since alcohol can cause a temporarily high sugar but also make sugars low, the overall advice of endocrinologists, said Dr. Gilbert, assistant professor at University of Toronto, is that those with diabetes should not drink excessively and if imbibing at all should check their blood sugars often. He even recommends patients set their alarms for the middle of the night to check their sugars.

“It’s not forbidden,” he says “but moderation would be encouraged.”

For street people who have diabetes, their control of their disease could be potentially worse due to more variable blood sugars as they experience highs and lows.

“It can really cause a lot of variability in the blood sugars thereby adding to the roller coaster phenomenon, he said. “ People who live on the streets often have other barriers to achieving proper blood sugar control and drinking may make it that much worse.”

In answer to your question, drinking can worsen the diabetes in patients, whose homes are the city’s streets, making them vulnerable to hypoglycemia.

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Lisa Priest is Sunnybrook’s Manager of Community Engagement & Patient Navigation. Her blog Personal Health Navigator provides advice and answers questions from patients and their families, relying heavily on medical and health experts.  Her blog is reprinted on with the kind permission of Sunnybrook Health Sciences Centre.  Send questions to

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