Parkview Health Logo

B12 deficiency and your stomach

Last Modified: December 28, 2021

Family Medicine

B12 and your stomach

This post was written by Reshi Kanuru, MD, PPG – Gastroenterology.

Over the years, we have found that vitamin deficiencies can play a role in certain symptoms and diseases. For example, low vitamin D levels can lead to osteoporosis and an increased risk of fractures. One essential vitamin that is important for our body to function properly is vitamin B12.

What is vitamin B12?

Vitamin B12 is an essential vitamin that we primarily obtain from our diet. It’s needed to produce the cells in our body and plays a vital role in the functioning of our nervous system. Generally, we have large stores of vitamin B12 in our body and can go months, even years without it before reaching low levels. However, it’s important to identify a deficiency early on to prevent the consequences of low B12.

What are the signs and symptoms of B12 deficiency?

A B12 deficiency can lead to many changes in the body. Usually, symptoms are subtle and can include feeling more irritable than normal, forgetting things easier and even difficulty with balance. As a B12 deficiency worsens, it can dramatically impact our nervous system causing numbness with loss of feeling in our arms and legs. These effects are typically reversible once proper B12 levels have been restored.

As previously mentioned, vitamin B12 is vital in the creation of cells within our body. Red blood cells help carry oxygen throughout the body and require vitamin B12 to function. If vitamin B12 is low this causes a change in the size of the red blood cells. In fact, the red blood cells produced when someone is deficient are larger than normal and known as macrocytosis. A deficiency can also lead to anemia, which means your body does not have enough red blood cells to perform normally. Understanding the perceivable symptoms that accompany a B12 deficiency is important, but it’s also imperative to know who is at the greatest risk.

What are the causes of B12 deficiency?

There are several risk factors that can assist in identifying those who are at an increased risk of becoming B12 deficient. The most common cause of a B12 deficiency is a lack of it in our diet. Although a plant-based diet, like veganism, is extremely beneficial to your overall health it can result in a B12 deficiency due to the lack of animal protein. We also see a lack of vitamin B12 in those that drink excessive amounts of alcohol. Without moderation and a healthy balanced diet, people that drink large amounts of alcohol can become vitamin B12 deficient.

When diet is not an issue, B12 deficiency generally has to do with an inability to absorb the vitamin properly. B12 requires special proteins and stomach acid to be adequately absorbed in the small bowel or terminal ileum, which is the last part of the small bowel before connecting to the colon.

A deficiency develops when any of the key steps in B12 absorption are disrupted. For example, pernicious anemia, an autoimmune disease of the stomach, can cause low B12 levels. In pernicious anemia, the body attacks the glands that secrete these essential proteins for B12 absorption. Without these proteins we become deficient. The risk for pernicious anemia and B12 deficiency can sometimes be identified during an upper endoscopy, a test that is utilized to look at the stomach. During this procedure, we can see where the stomach appears worn down or atrophied. Atrophy in the stomach can be a sign of pernicious anemia but also a key indicator of other disorders as well.

We can also see vitamin B12 deficiency in those who undergo major surgeries like gastric bypass. Why? Because after gastric bypass surgery the amount of acid and essential proteins secreted by the stomach are severely decreased, preventing crucial vitamin B12 absorption.

Crohn’s disease, an autoimmune disease, can also result in B12 deficiency. Crohn’s is an inflammatory disease that can cause ulcerations throughout the GI tract, specifically affecting the small bowel and colon. If there is uncontrolled inflammation in the terminal ileum, this will lead to vitamin B12 deficiency. At the same time, those affected with Crohn’s often undergo surgeries that involve the removal of at least a portion of the terminal ileum, placing them at further risk for a vitamin B12 deficiency. Even medications can cause a deficiency, which is why it’s important to only take those you absolutely need and have been prescribed by a physician.

How is B12 deficiency treated?

A vitamin B12 deficiency can be treated in several ways. First, if a deficiency is due to a diet low in B12 then the next step is to increase the foods that contain the vitamin. Those who receive enough B12 in their diet but remain deficient may need to take the next step and get extra vitamin B12 through other sources. Vitamin B12 can be given via injection or high doses of oral medication to increase the stores of B12 in the body.

The key takeaway? A vitamin B12 deficiency can occur for a variety of reasons, which is why it’s important to speak with your doctor. Together you can decide whether vitamin b12 testing needs to be completed, symptoms, risk factors and the possibility of a vitamin B12 deficiency.

Related Blog Posts

View all posts