Can a vitamin C supplement cause a blood sugar spike if I have diabetes?

If you have diabetes and test your blood with a glucose meter and glucose testing strips, taking an excess of vitamin C may cause a false “low” blood sugar reading. That’s because the vitamin interferes with an enzyme in the test strip. If you have diabetes, you may want to steer clear of supplements. Instead, consider getting your daily dose of vitamin C directly from foods rich in this vitamin. That would include citrus fruits and berries (just remember to follow your doctor’s dietary recommendations when consuming foods naturally high in sugar) and a variety of vegetables. If you still want to take a supplement, use a time-release form of vitamin C and stick to about 250 mg daily.
Always check with your doctor if you have a health condition before taking any supplements.

Continue Learning about Diabetes


Diabetes mellitus (MEL-ih-tus), often referred to as diabetes, is characterized by high blood glucose (sugar) levels that result from the body’s inability to produce enough insulin and/or effectively utilize the insulin. Diabetes ...

is a serious, life-long condition and the sixth leading cause of death in the United States. Diabetes is a disorder of metabolism (the body's way of digesting food and converting it into energy). There are three forms of diabetes. Type 1 diabetes is an autoimmune disease that accounts for five- to 10-percent of all diagnosed cases of diabetes. Type 2 diabetes may account for 90- to 95-percent of all diagnosed cases. The third type of diabetes occurs in pregnancy and is referred to as gestational diabetes. Left untreated, gestational diabetes can cause health issues for pregnant women and their babies. People with diabetes can take preventive steps to control this disease and decrease the risk of further complications.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.