Vitamin B 12 and Health in Old Age

Abstract

Vitamin B12 deficiency is common in old age. Frequent causes of vitamin B12 deficiency in older people include atrophic gastritis, intestinal malabsorption, drugs (e.g., metformin and proton-pump inhibitors), partial gastrectomy and vegetarianism. While more severe deficiency states are known to cause megaloblastic anemia and neurological syndromes, subtle deficiency is often asymptomatic. Although it is generally advisable to initiate vitamin B12 supplementation when there is evidence of metabolic deficiency (e.g., raised methylmalonic acid or homocysteine), or evidence of malabsorption (e.g., reduced transcobalamin), the potential benefits of supplementation in asymptomatic individuals remain unproven. This paper reviews the evidence that subclinical vitamin B12 deficiency may have adverse health outcomes in the longer term and that a proactive approach in the correction of deficiency may be justified.