B Vitamins

Question 1

Ester is a 75 year old widow who has had failing health since the death of her husband 7 years ago. She is emaciated and has several small punctate hemorrhages under the skin on her arms and legs, she has diarrhea, anemia, and her eyes have inflammation in the conjuctiva and margins of the lids, and she has photophobia. She has deep, raw and painful fissures in the corners of her mouth and her tongue is swollen and sore. She was treated with thiamine, nicotinamide, liver oil, and vitamin C. All symptoms except photophobia and fissures on her tongue and corners of her mouth resolved. Which vitamin supplement should she also have?

Answer 1

d. Riboflavin

Question 2

Which sulfur containing molecule will support Krebs cycle?

Answer 2

c. Alpha-lipoic acid

Question 3

Beri Beri can present as “wet” beri beri is associated with cardiovascular dysfunction, while “dry” beri beri is associated with neuropathy. In wet beri beri, clinical presentation is caused by impaired erythrocyte function, and so the enzyme __________ is not functioning without thiamine, while in dry beri beri, the presentation of neuropathy is primarily associated with the lack of ___________ enzyme activity without thiamine. (Hint: consider the difference in metabolism between erythrocytes and neurons)

Answer 3

c. transketolase, alpha-ketoglutarate dehydrogenase

Question 4

Which vitamin is important in stimulating glucokinase in pancreatic beta cells, and also required for carboxylase reactions?

Answer 4

a. Biotin

Question 5

Trina is a 50 year old woman who smokes 40 cigarettes and drinks half a bottle of gin (equivalent to 10 drinks) each day. Trina restricts her food intake for weight control, and has a BMI of 17. She presents with blistering on her ankles and dorsal region of her feet, and a rash on her hands, forearms, and periorbital skin. Trina has cyclic diarrhea and constipation. Prednisolone cephalexin treatment did not reduce her blisters or rash. However, after 1 week of 50 mg twice daily treatment with ________ the symptoms improved. Trina declined any further treatment for counseling, but did consider nutrition advice.

Answer 5

a. nicotinamide

Question 6

Which B vitamin causes toxicity, and what is the primary clinical observation of toxicity?

Answer 6

b. Pyridoxine, peripheral neuropathy

Question 7

Which enzyme reaction does NOT require FAD or FADH2?

Answer 7

c. NADH dehydrogenase

Question 8

Hyperlipidemia could decrease with which vitamin supplement due to the increased rate of beta-oxidation and commitment of acetyl-CoA to Krebs cycle instead of cholesterol biosynthesis?

Answer 8

d. Pantothenate

Question 9

Which vitamin is essential for producing neurotransmitters, heme, amino acids, nucleic acids, and glucose?

Answer 9

d. Pyridoxine

Question 10

Which vitamin would be required to convert tryptophan to nicotinamide?

Answer 10

d. Pyridoxal phosphate