Chandler Marrs

Are You Vitamin B12 Deficient?

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Most women have a basic understanding of the relationship between vitamin B9 – folate or folic acid and health. Any woman who has ever been pregnant knows that folate deficiencies can cause neural tube defects in the developing fetus. To prevent these complications, we are given prenatal vitamins that contain folic acid. Folic acid is also added to a myriad of food products. Unfortunately, folate or vitamin B9 is only part of the equation. Vitamin B12 (cobalamin) must also be sufficient and maternal vitamin B12 deficiencies also lead to neural tube defects in the developing fetus. Beyond pregnancy, however, vitamin B12 deficiencies in children and adults elicit a host of debilitating and even deadly central nervous system symptoms, sometimes mistaken for multiple sclerosis or other ill-defined and unexplained conditions. As is the case with many apparently complicated conditions, Vitamin B12 is not often tested. Even when tested, the reference ranges are out of date and ill-defined, and so, deficiencies are not recognized easily.

Why Do I Need Vitamin B12?

Vitamin B12 is involved with a staggering number of physiological functions. One of its most important roles is in the formation of red blood cells. Individuals lacking an intrinsic factor to absorb dietary B12 (as in pernicious anemia), have a lower than normal number of red blood cells. Without enough vitamin B12, the red blood cells don’t divide normally and are too large. Vitamin B12 is also involved in the synthesis of the myelin sheaths around nerve fibers. There is a growing relationship between multiple sclerosis, which involves the disintegration of myelin and brain white matter and vitamin B12 deficiency. Finally, B12 is involved in approximately 100 functions including DNA, RNA, hormone, lipid and protein synthesis. Many women have dysregulated hormones connected to vitamin B12 deficiency. With so many core but disparate functions, it is easy to see why vitamin B12 deficiencies can be difficult to diagnose and devastating if left untreated.

How Common is B12 Deficiency?

The data suggest B12 deficiencies in the general population range from 3-6%. However, and this is a big however, individuals over the 60, women, vegetarians and vegans have as high as a 20-25% vitamin B12 deficiency rate. Vitamin B12 is found in the diet in red meat, dairy, fatty fishes and some vegetables. As more people refrain from red meats and dairy, deficiencies in B12 are on the rise. More importantly, because of increased medication use, the physiological demands of pregnancy and hormones, women are particularly susceptible to lower vitamin B12 concentrations. These deficiencies can be compounded as we age and the ability to absorb the vitamin decreases. The most common causes of vitamin B12 deficiency are, diet, pernicious anemia, medication, Hashimoto’s thyroid disease, and genetics (the MTHFR mutation).

Common Medications that Deplete Vitamin B12

Are you Vitamin B12 Deficient?

You might be. Many women are deficient in vitamin B12 and don’t even know it. The symptoms develop gradually over years and are often attributed to other conditions, such as MS, Parkinson’s, and a variety of psychiatric conditions. Research suggests that fully 74% of patients with vitamin B12 deficiency present with neurological symptoms. Here are some of the symptoms of vitamin B12 deficiency.

  • Tremors
  • Numbness and parathesias – tingling and other odd sensations in the extremities (~33%)
  • Gait (walking) and balance disturbances (~12%)
  • Loss of position sense
  • Psychiatric symptoms and cognitive difficulties (~3%)
  • Weight loss (~50%)
  • Low grade fever (~33%)
  • Muscle pain and weakness
  • Fatigue and apathy

Vitamin B12 Testing

Vitamin B12 status is typically assessed via a blood test. Normal ranges can be found here. As noted above, there is evidence to suggest that blood levels may not accurately reflect tissue levels and so many women may show normal blood levels of vitamin B12 but are deficient nonetheless. Other tests that may be of value include, elevated homocysteine levels and/or elevated methylmalonic acide levels. Elevated homocysteine levels are present in a number of conditions, including cardiovascular disease, thyroid disease and chronic migraine. Homocysteine may not be a sensitive indicator of vitamin B12 deficiency. However, it is a good marker of general ill-health. So far, the most accurate test for vitamin B12 is urinary methylmalonic acid testing.

If you think you might be deficient, here is a simple checklist to take before seeing your doctor. It is provided by the Pernicious Anemia Society: Checklist for Vitamin B12 Deficiency.

To learn more about Vitamin B12 Deficiency, watch this video.


Chandler Marrs MS, MA, PhD spent the last dozen years in women’s health research with a focus on steroid neuroendocrinology and mental health. She has published and presented several articles on her findings. As a graduate student, she founded and directed the UNLV Maternal Health Lab, mentoring dozens of students while directing clinical and Internet-based research. Post graduate, she continued at UNLV as an adjunct faculty member, teaching advanced undergraduate psychopharmacology and health psychology (stress endocrinology). Dr. Marrs received her BA in philosophy from the University of Redlands; MS in Clinical Psychology from California Lutheran University; and, MA and PhD in Experimental Psychology/ Neuroendocrinology from the University of Nevada, Las Vegas.


  1. I recently found out with a DNA test I have mthfr gene mutations which symptoms I do have, my body has to use active forms of b12 and folic acid, i.e. methyl folate or it wont reconize it causing all my issues over the past several decades no wonder I am in such a mess now.. please look into MTHFR gene mutations for your methylation pathway issues!! Hard for our bodies to detox out crap and hard for our bodies to make glutathione for proper detoxing. THANK GOD I found out and hope its not too late!! Liposomal glutathione is best if you cant get glutathione IVs as well as Liposomal Vit C is best GOOGLE IT!! GOD BLESS

    • Hi Renee, I am glad you found out. Apparently, that is more common than recognized. Would you be interested in writing about the MTHFR symptoms and support groups?

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