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Do You Know Your Vitamin B12 (Cobalamin) Levels?

When was the last time you were tested for vitamin B12? What are the symptoms of a deficiency? Age and meds can cause a cobalamin deficiency.
Do You Know Your Vitamin B12 (Cobalamin) Levels?
Vitamin B12 (cobalamin) in a syringe ready for injection with vials in the background; Vitamin B12 injections

Most people do not think much about Vitamin B12, also known as cobalamin. It does not get the same attention as vitamin D, vitamin K or vitamin C. And yet this water-soluble nutrient is crucial for every cell in your body. Red blood cells require cobalamin. So do nerve cells. Without adequate levels of vitamin B12, people develop pernicious anemia. They may also experience neuropathy or nerve pain. The brain does not function well without adequate levels of B12. Sadly, though, many health professionals do not order vitamin B12 testing. That could be a serious mistake.

Stomach Acid and Vitamin B12:

People have been told for decades that stomach acid is their enemy. Commercials for acid-suppressing drugs like Nexium (esomeprazole), Prevacid (lansoprazole) and Prilosec (omeprazole) are convincing. Can such proton pump inhibitors (PPIs) affect cobalamin levels? 

As people age, inflammation of the stomach lining may reduce their ability to produce stomach acid. Researchers wondered if this condition, called atrophic gastritis (AG), leads to reduced absorption of vitamin B12. They also considered the question of whether acid-suppressing drugs such as omeprazole or esomeprazole affect vitamin B12 levels (American Journal of Clinical Nutrition, June 16, 2021}.

Over 3,000 Irish volunteers were recruited for this study between 2008 and 2012. Here is what the investigators discovered:

“In conclusion, older adults who have AG and/or higher-dose PPI use are more likely to have indicators of vitamin B-12 deficiency. Fortified foods, if consumed regularly, are associated with enhanced vitamin B-12 status, but higher levels of added vitamin B-12 than currently provided could be warranted to optimize status in older adults at greatest risk of food-bound malabsorption related to hypochlorhydria [low stomach acid]. Research is warranted to investigate further the relations of AG and PPI use with vitamin B-12 status in older age.”

In other words, either high-dose PPI use or atrophic gastritis are associated with suboptimal levels of vitamin B12.

Readers Weigh in on Cobalamin Deficiency:

Q. People who have had a gastric sleeve procedure may develop vitamin B12 deficiency. I became aware of this when I started feeling like a dead slug and started researching the symptoms.

After taking a supplement daily, I noticed a difference in about three days. I continue to take vitamin B12 and now feel well.

A. Weight-loss surgeries like yours can make it much harder for people to absorb adequate nutrients. Cobalamin is crucial for well-being, as the lack can result in severe fatigue as well as other problems. We trust your doctor is now monitoring your vitamin status on a regular basis.

Nerve Problems from Cobalamin Deficiency:

Q. In 2016 I was admitted to the hospital with numbness in my groin, legs, arms and hands. A week of blood work and CT scans did not show a reason for the problem. After that week I was released with no treatment and no improvement.

I subsequently reviewed my blood tests and noticed that my vitamin B12 level was extremely low. I went to my primary care doctor who started giving me B12 shots.

The problem cleared up within a couple weeks. I continue the shots today and have had no further trouble with this.

Symptoms of Vitamin B12 Deficiency:

A. Inadequate vitamin B12 levels can trigger neurological problems such as numbness and tingling (BMC Research Reports, Sep. 18, 2015).  Vegans, who consume no animal products whatsoever, are at particular risk of this condition. Patients who have had gastric bypass surgery are also vulnerable to this vitamin deficiency and usually need supplements (GE Portuguese Journal of Gastroenterology, April 2018).

People taking powerful acid-suppressing drugs called proton pump inhibitors (PPIs) or the diabetes drug metformin may also be vulnerable to a cobalamin deficiency. We think people who take such medications should routinely get tested for B12 levels.

You might ask your doctor if you could switch to oral vitamin B12 supplements. Some research suggests that pills can be as effective as shots but less expensive (Cochrane Database of Systematic Reviews, March 15, 2018).

Other Symptoms of Low Levels of Cobalamin:

  • Anemia can manifest as pale skin and tiredness
  • Nerve damage (numbness or tingling in feet and hands)
  • Dizziness, fatigue, shortness of breath
  • Weakness, weight loss and depression
  • Irregular heart rhythms (arrhythmias)
  • Psychological side effects (mood changes, dementia)

How to Restore B12 Levels:

Lee points out some important caveats:

“Often there is a cobalamin deficiency due to lack of production of intrinsic factor in the parietal cells in the fundus of the stomach. I’ve observed doctors giving B12 shots when the root cause was stomach cancer, especially around the gastroesophageal junction.

“Taking proton pump inhibitors that suppress the production of stomach acid can also cause lead to low levels of cobalamin. It is better to determine the cause of the deficiency rather than just supplement.”

Blood Tests Are Essential:

Ann in North Carolina encourages testing:

“I had problems after having been first on Prilosec and then Nexium for acid reflux for over 20 years. When I developed pernicious anemia, I literally crashed and burned. My B12 level was very low. In addition to the numbness and tingling in my hands upon waking, I experienced shortness of breath and unbearable fatigue and weakness.

“My doctor finally tested for cobalamin. When I tested low, I had to get vitamin B 12 shots for a year, along with extra iron.

“I had been complaining for a decade that I was very tired all the time. In addition, I was told my thyroid was ‘normal’ but it wasn’t. Anything over 2 is too high for me and I was a 6! I went to an endocrinologist who tested my thyroid and discovered I had Hashimoto’s which was also wreaking havoc.

“I finally weaned myself off the Nexium due to the other problems associated with it. To this day, I continue to take cobalamin liquid supplement, Vitamin D3 & CoQ10 since I’m on a low dose statin. Shame on these doctors who prescribe medications without following up with blood testing!”

Learn more about vitamins and testing in the book, Fortify Your Life by Tieraona Low Dog, MD. This is the best book on nutrients that we know of. You can listen to Dr. Low Dog and a leading nutrition researcher, Dr. JoAnn Manson, at this link.

They have differing perspectives on the value of vitamin supplements.

Share your story about vitamins in general and vitamin B12 in particular in the comment section below.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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