FNN 100 Lecture Notes - Lecture 6: Vitamin B12 Deficiency, Cobalamin, Intrinsic Factor

• School: Ryerson University
• Department: Nutrition and Food
• Course: FNN 100
• Professor: Jessica Wegener

Document Summary

Vitamin b12: corrinoids, vitamin b12 = cobalamin specifically cyanoconalamin (pharm. Form: 2 cobalamin coenzymes active in humans, hydroxy and cyancobalamins converted to active forms of vivo. Functions of vitamin b12: nerve function, blood formation, bone cell metabolism. Problems with parietal cells resulting in reduced production of intrinsic factor (preincuous. Pancreatic insufficiency less proteases, few enzymes available for break down. Vitamin b12 bioavailability: absorption increases with intake (higher intake from supplements and diet?, 9% from liver, 60% from chicken, assume 50% absorption in healthy adult foods we consume (assuming an animal base diet) Vitamin b excretion: bile > intestine > reabsorbed, some fecal excretion > unabsorbed dietary vitamin b12, sloughed intestinal cells, vitamin b12 from gut microflora. Intestinal reabsorption makes it unlikely in healthy adults: very long latent period in adults (>20 yrs, very short latent period in infants. Contaminated with soil, insects or other vitamin b12 containing substances.