Problem 1: Which has higher bioavailability: folate from natural food sources or folic acid from fortified food and supplements? Why is it more bioavailable?
Problem 2: List 3 top food sources for naturally occurring folate (not folic acid).
Problem 3: Describe why homocysteine concentration rises in a folate deficiency.
Problem 4: Delineate the relationship of methionine to SAM production and explain the biological importance of SAM.
Problem 5: Discuss the 4 potential diseases and/or conditions or practices that would be expected to adversely affect vitamin B12 absorption (note: this does not include a dietary deficiency, but what happens within the body separate from dietary intake, so this does not pertain to, for example, strict vegetarians). Explain the reason each of these adversely affects B12 absorption.
CASE STUDY: Vitamin B12 and Folic acid
During a diet history, you discover that your 73-year-old male client has been taking 4 mg (4,000 mcg) of folic acid daily for the past 5 years. In addition, he is a daily user of the antacid drug omeprazole (Prilosec).
Problem 6: Regarding vitamin B12, what is the main concern with very high doses of folic acid?
Problem 7: Explain the significance of the daily use of omeprazole in relation to vitamin B12 status.
Problem 8: What are at least 3 signs of vitamin B12 deficiency and two assessment tests would you run on this patient to assess his vitamin B12 status?
Problem 9: Describe in writing the various aspects of vitamin B12 digestion and absorption into the bloodstream, starting with the mouth - including protein-bound B12 in food (not supplements), and how B12 becomes free to proceed further through the absorption process. To receive maximum points, you should include in your discussion: IF (intrinsic factor), R (R proteins), pancreatic proteases, pepsinogen/pepsin, HCl, and the ileal receptor. Mention where IF and R proteins are produced. Note: You do not need to include transport after absorption into the hepatic portal vein. (Remember cobalamin = vitamin B12.)