By Dr. Shawna Darou, ND
I have been seeing lots of cases of vitamin B12 deficiency in the clinic lately, and wanted to write a short article about signs to watch for and causes of deficiency. Vitamin B12 is an essential water-soluble vitamin that is found in all animal foods – meat, poultry, fish, eggs and dairy. It is necessary to make red blood cells, nerve cells and to repair DNA. Fatigue is a universal sign of vitamin B12 deficiency since it is a form of anemia, but as you can see there are many other ways it can present.
Vitamin B12 deficiency symptoms include:
- fatigue and weakness
- anxiety and depression
- numbness or tingling in the hands, legs or feet
- mouth issues: swollen red tongue, mouth ulcers or burning tongue
- cognitive issues (difficulty thinking) or memory loss
- elevated heart rate and shortness of breath
- hair loss
Testing for vitamin B12 deficiency
It is very simple to test for a vitamin B12 deficiency with basic bloodwork, although sometimes it is not requested on a standard panel, especially if you are not vegetarian. Also important to note is that some labs do not flag vitamin B12 as deficient until it is very extreme. I would consider anything under 220 pmol/L to be deficient, and under 160 pmol/L to be very low. Another blood marker that can suggest a vitamin B12 deficiency is part of the CBC called the “MCV” or mean corpuscular volume. This reflects the size of the red blood cells, and a high value for MCV can indicate either a vitamin B12 or folate deficiency.
Causes of vitamin B12 deficiency
If your level is low and you are vegan or vegetarian, it is usually simply an issue of too low intake that needs to be supplemented. If you are regularly eating meat, fish, poultry or eggs and your level is still low, some further investigation is recommended.
Here are some of the other causes of low vitamin B12:
- Medications: Metformin, oral contraceptives, acid-blocking medications like proton-pump inhibitors (PPI’s)
- Celiac disease and non-celiac gluten sensitivity
- Pernicious anemia – an autoimmune condition with antibodies to parietal cells in the stomach
- H. pylori infection in the stomach
- Crohn’s disease
- Weight loss surgery (gastric bypass)
- Aging in general (less stomach acid means less B12 absorption)
Treatment for low vitamin B12
Finally, treating a vitamin B12 deficiency is very simple with either injections or supplementation. Cases where levels are very low (< 160 pmol/L) generally indicate gut absorption issues, so injections are recommended here while you are looking for the underlying cause. If the vitamin B12 level is low to moderately low (anything above 160 pmol/L), oral sublingual supplements will generally work very well to bring levels up. It is then important to retest after 2-3 months of treatment to ensure that levels are optimized and determine a maintenance plan for longer term support.
Once levels are restored to an optimal level, some symptoms will improve quite quickly such as energy, mood, sleep and shortness of breath. All neurological symptoms tend to take a while longer because the nerves actually need to repair. This includes cognitive changes, numbness and tingling and mouth issues. They do improve, but it can take months instead of weeks.
If you suspect that you may have a vitamin B12 deficiency based on the symptoms listed above or use of medications that cause a deficiency, the next step is a very simple blood test. From here we look at possible causes and get you started on a plan to restore your levels quickly. Please ask at your next appointment.