Vitamins for Type 2 Diabetes: Recommendations

People with type 2 diabetes may be interested in learning if vitamin supplements may be helpful for treatment. Type 2 diabetes is treated with lifestyle and dietary changes and, in some cases, medications. Nutrients are best derived from food sources, but in a true deficiency, supplements may be helpful.

It’s challenging to understand the best way to use supplements and which ones will be helpful for type 2 diabetes. Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

This article will discuss the use of vitamin supplements and if they play a role in the management of type 2 diabetes.

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Are Supplements Beneficial for Managing Type 2 Diabetes?

The best way to get all the vitamins and minerals needed by the body is through food. This is because food also contains many of the other substances the body needs to use vitamins effectively.

However, a lack of certain vitamins can occur for various reasons, including from taking some medications. Supplements can help get those levels back up to where they should be.

While there is a place for supplementation, vitamins haven’t been shown to be effective or reliable in managing blood sugar. If drugs are being used to manage your diabetes, know that vitamins, minerals, or other supplements, aren’t a good substitute or replacement for those medications.

Who May Not Benefit From Supplements

Vitamins and other types of supplements are also not without the potential for adverse effects. Any supplement can have unintended effects or may not be absorbed well.

In addition, supplements cost money, and one potential harm is spending money on a product that doesn’t turn out to work as well as is hoped. The research on vitamins for type 2 diabetes is still ongoing, so it’s important to keep up-to-date on the latest information.

Some supplements may interact with diabetes medications. This could mean that the effects of the medication are either made stronger or weaker, neither of which is helpful in managing a complicated condition like diabetes.

At times, this can even be dangerous, which is why it’s so important to talk with a healthcare provider before using supplements.

Best Vitamins and Minerals for Type 2 Diabetes 

There are a few vitamins and supplements that are often thought about or discussed when it comes to type 2 diabetes.

Thiamine (B1) 

Some people with diabetes may be deficient in thiamine, or vitamin B1. Because thiamine is important to many body systems, it’s important to have the right levels in the body.

A lack of thiamine might be the cause of some types of neuropathy (nerve damage). Correcting the deficiency with B vitamin supplements may be helpful in those cases.

One study showed that a thiamine supplement can help with the deficiency and also in improving lipid levels (fatty compounds found in the blood). However, this research wasn’t able to show any effect on underlying diabetes.

A meta-analysis, which is a high-level look at many different studies, investigated thiamine and its effect on type 2 diabetes. It found that people who took between 100 and 900 milligrams (mg) of thiamine a day didn’t see any effect on their blood glucose control.

Research authors note, however, that data were collected from mostly small studies that didn’t include large numbers of people, research was only conducted at a single site, and the follow-up was conducted after only about three months. These are considered limitations of the analysis. They call for a larger study that includes many more subjects and locations to better understand the effect of thiamine on type 2 diabetes.

A healthcare provider may recommend supplementing with thiamine or other B vitamins if there is a deficiency or if there are symptoms of neuropathy. But taking supplements is not a substitute for any diabetes medications that are needed.

Foods that are sources of thiamine include asparagus, beef liver, black beans, edamame, eggs, fortified cereals and whole-grain products, lentils, macadamia nuts, and pork loin.

Vitamin B12

A vitamin B12 deficiency may be a concern for some people who live with type 2 diabetes. Food sources of vitamin B12 include beef liver, clams, dairy products, eggs, fortified cereals or nutritional yeasts, chicken, fish, and meat. Vitamin B12 isn’t found in plants, so this vitamin is a special concern for people who follow a plant-based diet.

Vitamin B12 supplements are sometimes recommended for people with long-standing or complicated diabetes or neuropathy.

The authors of one study on vitamin B12 and folate supplementation in people with diabetes were cautiously optimistic about the benefits of using it earlier in the disease course. The theory is that because vitamin B12 does not pose a risk of adverse side effects, supplementing should be studied further and considered for some people with diabetes.

However, it is possible to have symptoms caused by high levels of vitamin B12, as some case reports show. For that reason, it’s important to discuss taking a supplement with a healthcare professional.

Metformin and Vitamin B12

Metformin is a drug commonly used to treat type 2 diabetes and other related conditions. People who take metformin may be at risk for a vitamin B12 deficiency.

One study showed that 22{7b6cc35713332e03d34197859d8d439e4802eb556451407ffda280a51e3c41ac} of people taking this drug had vitamin B12 levels that were too low. A multivitamin may have helped some people prevent or reverse a deficiency.

Another study showed that people who took metformin had vitamin B12 levels that were 10{7b6cc35713332e03d34197859d8d439e4802eb556451407ffda280a51e3c41ac} lower than those who didn’t take this drug. Monitoring vitamin B12 levels could be recommended for those who take metformin in the long term.

Vitamin D

Vitamin D is the subject of many studies of type 2 diabetes and other conditions. What’s not yet well understood is if a lack of vitamin D contributes to the development of certain diseases or if the diseases themselves cause the deficiency.

Experts haven’t yet agreed about the use of vitamin D supplements for people who don’t have a true deficiency. There’s also no complete agreement about the use of vitamin D in type 2 diabetes beyond correcting deficiencies.

One meta-analysis found that vitamin D supplements were better for some people than a placebo (inactive medication) in reducing insulin resistance, which occurs when the body does not respond to insulin, a hormone that allows the body to use blood sugar as it should. However, no effect was shown on fasting blood glucose, hemoglobin A1c (HbA1c), or fasting insulin levels.

A vitamin D deficiency can be diagnosed with a blood test. At this point, there aren’t any guidelines to help people with diabetes sort through supplementing with vitamin D. For that reason, supplements should be recommended by a healthcare provider. Doing so can help avoid taking too much or not enough.

Vitamin D and Blood Sugar

People with type 2 diabetes who have low vitamin D levels might have blood sugar that is less well controlled. One study showed that a supplement might help people with low vitamin D levels control their blood sugar levels better. People with diabetes will want to ask their healthcare provider about using a vitamin D supplement and how it can fit into a treatment plan.

Vitamin D can be found in beef liver, fatty fish (salmon, trout, tuna, and mackerel), egg yolks, mushrooms, and foods fortified with it, such as dairy products and cereals. It also is produced by the body through exposure to sunlight on the skin.


People who live with type 2 diabetes may have low levels of magnesium. Some good food sources of magnesium are bananas, black beans, edamame, fortified cereals, nuts (almonds, cashews, peanuts), pumpkin or chia seeds, salmon, soy milk, and spinach.

Low levels of magnesium are associated with an increased risk of developing diabetes. Supplementing magnesium in people with type 2 diabetes may improve fasting and post-meal glucose levels and insulin sensitivity.

However, as the authors of one meta-analysis point out, no large-scale clinical trials would support the routine use of magnesium supplements in type 2 diabetes.

One meta-analysis showed that 12 weeks of additional magnesium in people with type 2 diabetes was associated with improved blood pressure levels. However, the authors call for more rigorous studies to confirm this potential benefit.

Increasing magnesium levels have also been studied in stroke, which is a complication of diabetes. Higher magnesium levels may be associated with a lower risk of some types of stroke. However, there is a need for randomized controlled trials to confirm the effect and make recommendations.

What to Consider in Selecting Vitamins for Diabetes

Low levels of vitamins and minerals can be diagnosed with a blood test. People with type 2 diabetes may have regular blood tests to monitor vitamin levels. If a deficiency is found, it’s important to make a plan to address it with the help of healthcare providers.

The first focus is on eating a diet that meets nutritional needs and provides enough vitamins and minerals. Working with a healthcare provider such as a dietitian can help in making meal plans and knowing which foods will be most helpful in the case of a deficiency.

There are many types and brands of vitamin supplements on the market. The Food and Drug Administration (FDA) does not regulate these supplements. Choosing one of high quality is important to not waste money and to get the desired results.

One way to choose a supplement containing the right amount of nutrients is to look for certification. There are independent companies that test supplements to ensure they contain what they’re supposed to, don’t contain ingredients that shouldn’t be in them, and are standardized so that each bottle sold includes the same amount of vitamins and minerals.

Look for a Certificate of Analysis (COA) on the supplement’s label. This means that one of the third-party companies has tested it in their lab. Some of the companies that do this are Banned Substances Control Group (BSCG), ConsumerLab, National Sanitation Foundation (NSF) International, and U.S. Pharmacopeia (USP).

For some people, a single supplement may be recommended. But a multivitamin might make more sense for those who have multiple deficiencies or might develop them in the future. 

Note About Use and FDA Approval

Unlike drugs, the FDA does not approve dietary supplements for safety and effectiveness before they are marketed. Look for supplements that have been tested by a trusted third party, such as USP, ConsumerLab, or NSF.

Third-party testing does not mean supplements are necessarily safe for everyone or effective in general. It is essential that you discuss any supplements you plan to take with your healthcare provider to avoid interactions with your medications and other supplements you are taking.


People with type 2 diabetes may have vitamin deficiencies for a variety of reasons. Blood tests can be used to uncover a lack of certain vitamins and minerals and might be used as a part of regular care for diabetes.

To get the most effective use from any supplements, it’s important to choose quality brands and to get help from a healthcare provider to understand the dosage that’s needed.

A Word From Verywell

Regular care for diabetes will mean making lifestyle changes and might mean using medications to manage blood glucose levels. Vitamin deficiencies can be common in people who have diabetes and could cause symptoms or lead to complications.

People with diabetes will want to understand what vitamins and minerals they might be lacking, what symptoms these deficiencies could cause, and how to make a plan with a healthcare provider to correct any problems.

In some cases, it may take some self-advocacy to get the right tests done, and possibly a recommendation or a referral to a dietitian or other healthcare professional focused on nutrition. 

Frequently Asked Questions

  • Can vitamin D deficiency cause type 2 diabetes?

    The role that vitamin D plays in diabetes is not well understood. Whether a deficiency contributes to the development of the disease is still under study. Getting enough vitamin D is important to overall health. If a deficiency is suspected, talking to a healthcare provider and getting levels tested may help.

  • Can people with diabetes take vitamin C?

    Getting enough vitamin C is important in diabetes. People with diabetes may need a supplement if levels are found to be low and should be discussed with a healthcare provider. One study showed that it’s important for people with diabetes to get enough vitamin C.