Metformin is a first-choice medication primarily prescribed to people with type 2 diabetes to lower their blood sugar. It is both highly effective and generally well-tolerated, and it is the first-line treatment recommended by the American Diabetes Association.
Unlike other medications, metformin doesn't require a person to avoid any particular foods and it is also not associated with weight gain, like some other diabetes medicines, Elizabeth Halprin, MD, clinical director of adult diabetes at Harvard's Joslin Diabetes Center, tells LIVESTRONG.com.
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However, metformin does interact with alcohol, so it's best to discuss with your doctor before drinking while taking the drug.
Read more: 7 Foods That Won't Cause Blood Sugar Spikes
Metformin and Alcohol
As a general rule, people with diabetes should moderate their alcohol intake, because alcohol impairs the liver's ability to store and release glucose (aka blood sugar). This is a problem for people with diabetes because their bodies already struggle to manage blood glucose.
In addition, drinking alcohol on an empty stomach can lead to low blood sugar (hypoglycemia), per the University of California, San Francisco. This alcohol-related complication is more common in people taking insulin or diabetes meds that increase insulin levels. Metformin does not increase insulin levels, so alcohol-induced hypoglycemia is less likely to occur in people who take it.
Metformin-Associated Lactic Acidosis
When the body uses glucose as energy, it generates lactic acid. Metformin increases the amount of lactate — the underlying compound of lactic acid — in the blood, as described by a study published in the February 2016 issue of Metabolism.
This is typically a benign effect, but according to a small study published in Scientific Reports in October 2017, too much alcohol coupled with a thiamine (vitamin B1) deficiency can lead to a buildup of lactate. This combination of metformin and alcohol can result in too much lactic acid in the blood, a toxic condition that can lead to lactic acidosis, in people with acute or chronic alcohol abuse.
Metformin-associated lactic acidosis (MALA) is rare but potentially life-threatening. Per the Metabolism study, it occurs in fewer than 10 out of every 100,000 people per year. While the risk of lactic acidosis for people with diabetes is low, your risk is higher if you have impaired liver or kidney function or congestive heart failure.
If you're taking metformin, it might still be OK for you to drink in moderation. According to the Mayo Clinic, "moderation" means one drink per day for women (and men over 65), and two drinks per day for men under 65. But discuss your alcohol consumption with your doctor because a no-alcohol lifestyle might be healthiest for you.
Look at Your Overall Diet
Metformin is designed to lower blood sugar levels. But it is much less effective when it's not accompanied by a balanced, healthy diet. To get the most benefit from your diabetes medication (and to improve your overall health), try to limit or avoid foods that cause high blood sugar in the first place.
Foods containing simple carbs (sodas, candies, desserts) and refined carbs (white bread, white rice, pasta) are the biggest culprits when it comes to high blood sugar. Instead, opt for complex carbs like brown rice and whole-grain bread: These carbs have more dietary fiber and are therefore harder for the body to metabolize, which slows the release of glucose into the bloodstream.
Also, be sure to include lean proteins (such as turkey, fish and tofu) and fill half of your plate with nonstarchy vegetables (such as broccoli and leafy greens) at each meal, as that will also slow your carb metabolization.
Read more: The Best Nuts for People With Diabetes
- University of California, San Francisco: "Alcohol and Diabetes"
- Scientific Reports: "Prognosis of Alcohol-Associated Lactic Acidosis in Critically Ill Patients: an 8-year Study"
- Mayo Clinic: "Alcohol: Weighing Risks and Potential Benefits"
- Metabolism: "Metformin-Associated Lactic Acidosis: Current Perspectives on Causes and Risk"