Many vitamins and supplements are marketed to individuals with type 2 diabetes, but not all vitamins have the clinical evidence to back up their claims.
The American Diabetes Association (ADA) does not support the use of vitamins for people with diabetes, unless an individual has a diagnosed vitamin deficiency or is at a higher risk for a vitamin deficiency.
Before taking a vitamin supplement if you have type 2 diabetes, discussing the potential harms and benefits with your healthcare provider is a good idea.
Vitamins are important macronutrients that support general health and well-being. Though most people get all the vitamins they need from the food that they eat, there are some circumstances in which people with type 2 diabetes can benefit from taking a vitamin. But some vitamins can also cause harm to people with diabetes.
If you have diabetes, it’s important to look at the evidence before taking any vitamin supplementation. If you’re unsure whether or not a particular vitamin will cause you harm, reach out to your healthcare provider for guidance.
In this article, I’ll dive into the research behind vitamins for type 2 diabetes and explain which vitamins may cause more harm than good.
How Vitamins Can Help People with Diabetes
Most people get all the vitamins they need from their food. But in some cases, taking a vitamin supplement can help correct or prevent a vitamin deficiency.
People following strict low-calorie diets, the elderly, and some strict vegans can benefit from vitamin supplementation. The evidence behind vitamin supplementation for patients with diabetes isn’t conclusive, but there are some circumstances in which people with type 2 diabetes can benefit from taking certain vitamins. For example, research shows that specific vitamins may help reduce fasting glucose levels and the risk of cardiovascular disease in people with type 2 diabetes. Unfortunately, specific vitamins can also be dangerous for people with type 2 diabetes.
Before taking a vitamin, it’s important to look at the evidence behind vitamin supplementation and ask your provider whether or not it’s safe to use. At the end of the day, vitamin supplementation should never replace a healthy diet, medication, or other health provider-recommended diabetes treatments.
Research shows that people with diabetes are more likely to have a deficiency of vitamin B1 (also called thiamine). One study found that thiamine replacement can prevent the formation of harmful by-products of glucose metabolism, reduce oxidative stress, and improve blood vessel function. Another study found that vitamin B1 may help reduce kidney damage in people with diabetes-related kidney disease. Though more research is needed to determine whether vitamin B1 supplementation may benefit all people with type 2 diabetes, it may be beneficial for certain individuals.
People with type 2 diabetes who take the medication Metformin tend to have lower levels of vitamin B12. If you have a vitamin B12 deficiency due to taking this medication, taking a vitamin B12 supplement can help correct this deficiency. To learn whether or not you have a vitamin deficiency, talk to your healthcare provider about testing.
One study suggests that vitamin D supplements may help reduce insulin resistance in individuals with well-controlled A1c levels. Unfortunately, the research on using vitamin D as a treatment for diabetes is inconclusive. The American Diabetes Association (ADA) does not recommend taking vitamin D to support type 2 diabetes treatment unless you’re deficient in the vitamin.
Individuals with poor diets or diets high in processed foods are more likely to experience a magnesium deficiency. This is because magnesium is a vitamin found in whole foods such as whole grains, leafy vegetables, legumes, and nuts. One meta-analysis found that magnesium supplements may also help to reduce fasting glucose levels in people with type 2 diabetes, but the long-term benefits and safety of using magnesium are still inconclusive. Another systematic review and meta-analysis found that magnesium may help reduce the risk of cardiovascular disease in people with type 2 diabetes.
Taking a vitamin E supplement when you have type 2 diabetes could cause dangerous side effects. Specifically, vitamin E can interact with blood-thinning drugs used to treat heart disease and increase your bleeding risk. If you take warfarin or any other blood thinner, you may have higher levels of vitamin E already present in your blood. In that case, you should avoid vitamin E supplements. If you’re unsure whether you’re currently taking a blood thinner or at a higher risk of bleeding, talk to your provider before taking vitamin E or any other supplement.
According to the American Diabetes Association (ADA), no persuasive evidence exists to demonstrate that vitamin C supplements will benefit people with type 2 diabetes. According to the ADA, there is also little evidence that vitamin C will prevent diabetes complications.
Where to Find Vitamins
The US Food and Drug Administration (FDA) does not regulate vitamins and supplements. Though you can find vitamins and supplements in most drug and health stores as well as online, it’s a good idea to look for the United States Pharmacopeia (USP) seal on the bottle to ensure that you’re purchasing a higher-quality supplement.
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Frequently Asked Questions
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Can Vitamin B1 Reduce Kidney Damage? (2008).
Effects of oral magnesium supplementation on glycaemic control in Type 2 diabetes: a meta-analysis of randomized double-blind controlled trials. (2006).
Effect of magnesium supplementation on type 2 diabetes associated cardiovascular risk factors: a systematic review and meta-analysis. (2017).
Supplements to Lower Blood Sugar. (2022).
Vitamins and Type 2 Diabetes Mellitus. (2015).
Vitamins & Diabetes.
Thiamine deficiency in diabetes mellitus and the impact of thiamine replacement on glucose metabolism and vascular disease. (2011).
The Effect of Vitamin D Supplementation on Glycemic Control in Type 2 Diabetes Patients: A Systematic Review and Meta-Analysis. (2018).