Thank you for this post on a health issue of increasing relevance. ‘Increasing’ because the majority of vitamin B12 deficiencies fall into one of two categories: insufficiency of dietary intake or food-bound cobalamin malabsorption (FBCM).
While the former is an issue for vegetarians and vegans, the latter affects omnivores, particularly the elderly, and certain groups of patients. The latter are those on longer-term prescriptions of drugs such as PPIs and metformin, but they also include bariatric surgery patients. The increasing adoption of vegetarian diets, the increase in the proportion of the elderly, and the growing number of patients requiring PPIs, anti-diabetic drugs, and obesity surgery, all point to a rise in the prevalence of cobalamin deficiency.
The issue is further complicated by (a) a lack of gold-standard diagnostic criteria to define what ‘normal’ levels of Vit B12 should be and (b) a disconnect between neurological symptoms and haematological manifestation. That is, neurological symptoms of B12 deficiency may show up with apparently normal blood markers.
Fortunately, a healthy liver has a very large storage capacity for Vit B12, which can compensate for temporarily insufficient dietary intake or malabsorption issues for several years. But this also points to two vulnerable groups: infants and toddlers, whose mothers have been adhering to vegan diets during pregnancy and lactation, and who continue to feed their children a vegan diet, and the elderly, in whom a rising prevalence of FBCM coincides with depletion of hepatic Vit B12 reserves. In both populations the neurological consequences of undiagnosed and untreated Vit B12 deficiency can be dire and are always irreversible once they manifest.
Your post helps to increase awareness, not only about the need to monitor Vit B12 status but also about the need to prevent and treat Vit B12 insufficiency. Given the ease of prevention and treatment through oral or parenteral administration of Vit B12 this should not be a problem. Or, better still, through the adoption of a Vit B12 containing diet. Such a diet is the evolutionary normal for an ‘animal’ that cannot synthesize this essential nutrient.
