Intestinal Absorption and Hepatic Uptake of Radioactive Vitamin B12 in Various Age Groups and the Effect of Intrinsic Factor Preparations

Abstract

The measurement of the hepatic uptake of an orally administered standard dose of Co⁶⁰-labeled vitamin B₁₂ in 60 individuals of various age groups, 18 to 90 years of age, who were normal or had some irrelevant disorder, indicates a wide range of variation in the intestinal absorption of vitamin B₁₂. While there is no evidence of general impairment of intestinal absorption of vitamin B₁₂ as a function of advancing age, more individuals in the older group have impaired intestinal absorption of vitamin B₁₂ than at the younger age. In individuals over 60 years old absorption is significantly lower in subjects with gastric hypo- or anacidity than in the individuals of the same age group with normal or hyperacid gastric secretion. It appears that the measurement of the hepatic uptake of Co⁶⁰-vitamin B₁₂ might be helpful in the early recognition of vitamin B₁₂ absorption defects of a sprue-like or pernicious anemia-like type in this group at a yet pre-anemic and asymptomatic stage. The addition of a potent intrinsic factor preparation increases the hepatic uptake of radioactive vitamin B₁₂ over 25 per cent in almost one-half of the cases in all age groups. In as many others, no significant change was observed. Especially important, however, is the increased hepatic uptake in individuals of the older age group having a decreased or abolished gastric acidity, which is usually associated with impairment of secretory output of other gastric glandular secretions. The range of applications of intrinsic factor preparations in the correction of defective intestinal absorption of vitamin B₁₂ appears to embrace not only states of frank deficiencies of vitamin B₁₂ such as pernicious anemia or total gastrectomy, but also clinically latent partial defects of absorption due to decreased output of all of the secretions from gastric glands, including intrinsic factor.