The most common cause of vitamin B12 deficiency is malabsorption, the classic case being pernicious anaemia. An enzyme produced by the stomach cells (intrinsic factor), is needed for B12 (extrinsic factor) to be transported through the intestines and be properly absorbed. Aging, stress and stomach problems interfere with the body’s ability to produce the “intrinsic factor”. Hydrochloric acid is also required for the absorption of B12. At least 22 per cent of the population produces inadequate hydrochloric acid, so although dietary intake of vitamin B12 may be satisfactory, absorption is generally not.
Inadequate dietary intake of vitamin B12 is common in vegetarians and vegans, and also among the elderly due to poor nutrition, sometimes referred to as the “tea and toast diet”. Vitamin B12 is only found in significant amounts in animal protein foods, including meat, oily fish, egg yolks and dairy products. There are minute amounts in tempeh, and other fermented soy products; sprouts; mushrooms; and sea vegetables, such as kombu, kelp and nori.
Deficiencies are also common in those with a high alcohol intake. The widespread use of antacids and other commonly prescribes medications such as proton pump inhibitors are strong contributing factors in B12 malabsorption, by impeding gastric acid secretion. Laxatives also deplete B12 reserves.
Other important gastrointestinal causes of deficiency are coeliac disease and non-coeliac gluten intolerance. Even when there is a state of malabsorption, it can still take two to five years to develop a biologically significant B12 deficiency, as storage levels are high relative to daily requirements. (Gluten intolerance can result in the disruption of essential nutrients not just vitamin B12.)
Overcoming B12 deficiency
Prompt treatment of B12 deficient patients is required to prevent progressive, irreversible neurological and cognitive impairment. Intramuscular injections have been the mainstay of B12 deficiency treatment for years. Intramuscular injections are usually administered on a weekly basis for a month, and then a dose of 1000 mcg given on a monthly basis. This can be a painful procedure, particularly for elderly patients.
Fortunately, oral or sublingual supplementation is a very viable option. Recent clinical trails have shown that 1000 mcg of Cyanocobalamin (vitamin B12), taken orally, was effective in 100% of the patients tested, and no patients needed to resume vitamin B12 injections. The normal oral protocol is 2000 mcg doses daily for a month, followed by 1000 mcg doses weekly and then monthly. Daily doses of between 1000–2000 mcg are important to ensure enough of the vitamin is passively absorbed across the small intestine.
For patients who have problems swallowing, sublingual B12 is just as effective, where the tablet is dissolved in the mouth. B12 absorption is improved by taking pancreatic enzymes and betaine hydrochloride. The metabolism of B12 can be further advanced by prescribing probiotics at the same time, especially where there is damage the mucosal barrier (Leaky Gut Syndrome).