What You Need to Know About Diabetes and B12 Deficiency – A Guide

Posted March 2, 2020 by Clint Kelly - See Editorial Guidelines

Research among diabetes patients shows a prevalence of vitamin B12 deficiency among both type 1 and type 2 diabetes. However, vitamin B12 is essential for the human body to remain healthy. Therefore, in this article, we will discuss the correlation between diabetes and vitamin B12 deficiency.

There are multiple ways that vitamin B12 deficiency can occur. However, diabetes can put you at a higher risk of developing the deficiency.

Diabetes and B12 Deficiency

Diabetes and Vitamin B12 Deficiency: A study found that 22% of diabetic patients had vitamin B12 deficiency. The study also found that those taking metformin had an increased risk of having B12 deficiency. B12 deficiency may also contribute to diabetic neuropathy.

What is Vitamin B12?

Vitamin B12 is an essential nutrient, mainly found in animal proteins, that keeps the body’s cells healthy. B12 is also responsible for synthesizing, or replicating, DNA and providing structural stability to chromosomes.

Low levels of B12 can result in damage to DNA, which can lead to neurological problems down the road. Neurological issues can include Alzheimer’s or dementia. Certain cancers have also been associated with low levels of B12.

Ultimately, vitamin B12 is crucial for helping individuals stay healthy and avoid serious medical conditions from arising.

Symptoms of B12 Deficiency

B12 deficiency can result in anemia, which is a condition where you lack enough healthy red blood cells. If B12 deficiency is left untreated, it can lead to the following symptoms:

Diabetes and B12 Deficiency

  • Weakness
  • Tiredness
  • Fatigue
  • Shortness of breath
  • Heart palpitations
  • Pale skin
  • Diarrhea
  • Constipation
  • Loss of appetite
  • Numbness or tingling
  • Muscle weakness
  • Vision loss
  • Depression or behavioral changes
  • Colder than usual
  • Smooth tongue

Prevalency of Diabetes and B12 Deficiency

Several studies have demonstrated that there is a correlation between type 2 diabetes and B12 deficiency. B12 deficiency among diabetes patients may be due to patients being prescribed metformin.

Metformin is a popular medication prescribed to those with diabetes to help them control blood sugar. This medication is very useful in helping individuals manage their diabetes and control blood sugar levels. However, B12 deficiency is one common side effect.

The severity of vitamin B12 deficiency may depend heavily on the age of the patient and how long one has been taking metformin.

Low levels of B12 were recognized after about the fourth month of taking metformin. This will vary from individual to individual. Therefore, if you are taking metformin, you may want to consider having screening done for levels of vitamin B12 in your system.

This does not mean you should stop taking metformin. Metformin is a medication that is considered to be extremely beneficial for those struggling to control blood sugar levels. The best option is to talk to your doctor about incorporating a B12 supplement as part of your treatment.

It is not clear how metformin causes low levels of B12. One possible reason may be due to metformin causing overgrowth of bacteria in the small intestines that results in the deficiency.

The longer one has been taking metformin, or stronger doses, may put a patient at a higher risk. Older patients are also at a higher risk of developing a deficiency in B12.

Patients with type 1 diabetes are also at a higher risk for developing B12 deficiency when compared to the general population. This is due to the fact that those with type 1 have autoantibodies to the intrinsic factor. The antibodies prevent the B12 from binding to the intrinsic factor resulting in a deficiency.

Treatment of B12 Deficiency in Diabetes Patients

There are a few different options as far as how you can treat your vitamin b12 deficiency if you are diabetic. The first possible treatment option is to look at your diet.

We understand that veganism is a popular diet that has many health claims behind it, and we know that many do it for animal rights. However, since B12 comes from animal protein, it may be difficult to get the proper vitamin nutrients from a plant-based diet.

Adding animal protein in your diet may help boost your vitamin B12 levels. This includes poultry, seafood, eggs, and dairy products. It is best to incorporate these foods into your diet prior to becoming deficient in B12 as a way to prevent it.

If deficiency of B12 is severe, then injections of B12 may be recommended by your doctor. A B12 injection costs up to $80, depending on your location and insurance. The two common injections are cyanocobalamin and hydroxocobalamin. Typically, as part of maintenance therapy, an injection of 100-200 mcg is given once a month.

Vitamin B12 supplements can also be taken by mouth. Discuss what dosage your doctor suggest for an oral B12 supplement. It is typically taken once daily.

B12 and Diabetic Neuropathy

Those with diabetes and B12 deficiency may be at an increased risk for diabetic neuropathy. Neuropathy is defined as nerve damage, generally occurring in the legs and feet. The nerve damage can lead to numbness, muscle weakness, loss of coordination, and serious foot problems such as sores or ulcers.

Low levels of B12 can lead to anemia, as mentioned above, but can also lead to nerve damage. When high blood sugar caused by diabetes and B12 deficiency are combined, it can lead to a higher risk of nerve damage.

If blood sugar levels are not controlled, and the vitamin deficiency is untreated, then severe medical conditions can arise, some of which can be permanently debilitating.

The risk of diabetic neuropathy makes it essential for you to continually follow up with your doctor regarding lab results and overall health. Do not ignore the signs and symptoms of neuropathy.

How B12 Deficiency is Diagnosed

Diabetes and B12 DeficiencyIt is important to note here that you should not ignore any signs or symptoms associated with B12 deficiency. A blood test will determine if you are deficient in vitamin B12.

The healthy range of B12 levels is between 200 and 900 nanograms per milliliter (ng/mL). Individuals that are at the lower end of this scale may need to start taking B12 supplements, especially if they have diabetes.


We hope that this has given you a better understanding of diabetes and B12 deficiency. If you have any concerns or questions regarding your health, then consult your doctor immediately.

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