Vitamins

Question 1

What are vitamins

Answer 1

Vitamins are a group of chemically diverse organic compounds that an organism requires for normal metabolism. Apart from a few exceptions (e.g., vitamin D), the human body cannot synthesize vitamins on its own in sufficient amounts and must, therefore, ensure a steady supply through the diet.

Question 2

What is the difference between fat and water soluble vitamins in terms of storage

Answer 2

Vitamins are classified into fat-soluble vitamins, which the body can store, and water-soluble vitamins, which, with the exception of vitamins B9 (folate) and B12 (cobalamin), the body cannot store over significant periods of time and, therefore, require continuous intake.

Question 3

Vit A deficiency

Answer 3

Night blindness, 
Xerosis cutis
Bitot spots
Keratomalacia/xeropathalmia
Immunosuppression

Question 4

Eye sign of vit A deficiency

Answer 4

Bitot sqpots (grey triangles)

Question 5

Overall functions of vit A

Answer 5

Gene transcription
Coenzyme
Cell signalling

Question 6

Causes of vit A deficiency

Answer 6

Fat malaborption:
IBD, coeliac, CF, pancreatic insufficiency, cholestasis

Malnutrition

Question 7

Immune effect of vit A deficiency

Answer 7

Immunosuppression: vitamin A deficiency increases the risk of a measles infection taking a severe course.

Question 8

Functions of vitamin E

Answer 8

Protects against free radicals

Question 9

T/F Vit E deficiency is common

Answer 9

F. It is very rare

Question 10

Causes of vit E deficiency

Answer 10

Fat malabsorption disorders (e.g., cystic fibrosis)

Defects in genes that code for α-TTP

Question 11

Clinical features of vit E deficiency

Answer 11

Demyelination of:

the posterior column (proprioception and vibration sensation)

and

spinocerebellar tract  
(causes ataxia and symptoms similar to vitamin B12 deficiency)

Question 12

How to distinguish vit E from vit B deficiency

Answer 12

lack of hypersegmented neutrophils, megaloblastic anemia, and increased methylmalonic acid levels

Question 13

Other features of vit E deficeincy

Answer 13

Hemolytic anemia: deficiency results in increased fragility of erythr`ocytes and membrane breakdown
Acanthocytosis
Muscle weakness

Question 14

Function of vitamin K

Answer 14

Cofactor for γ-carboxylation of glutamic acid residues in vitamin-K-dependent proteins that are involved in

1) Coagulation: factors II (prothrombin), VII, IX, and X, proteins C and S
2) Bone formation: osteocalcin (bone Gla protein), matrix Gla protein

Question 15

What drug affects vit K synthesis and how

Answer 15

Warfarin inhibits the vitamin K-dependent synthesis of clotting factors and proteins!

Question 16

Causes of vit K deficiency

Answer 16

Liver failure (e.g., cirrhosis)
Fat malabsorption
Prolonged broad-spectrum antibiotic therapy
Vitamin K antagonists (e.g., warfarin)

Question 17

What causes vit K deficeicny in neonates

Answer 17

The neonatal intestine is sterile (no flora to synthesize vitamin K)
Vitamin K does not cross the placenta
Breast milk does not contain vitamin K
The neonatal liver is incapable of synthesizing the active form of vitamin K

Question 18

What is the clinical features of vit K deficeincy

Answer 18

Hemorrhage (e.g., petechiae, ecchymoses)

Vitamin K deficiency bleeding (VKDB)

Question 19

Which vitamin is injected at birth

Answer 19

vITAMIN k

Question 20

What is caused by vit b1 deficiency (thiamine)

Answer 20

Wernicke-Korsakoff syndrome

Beriberi

Question 21

What is caused by vit b2 deficiency (riboflavin)

Answer 21

Conjunctivitis with corneal vascularization

Cheilosis

Question 22

What is caused by vit b3 deficiency (niacin)

Answer 22

Pellegra:

Characterized by “the four D’s”: diarrhea, dermatitis/”da big tongue” (glossitis), dementia, and death - usually occurring in this order.c

Question 23

What cancer can cause pellagra

Answer 23

carcinoid syndrome, a disease in which neuroendocrine tumors along the GI tract use tryptophan as the source for serotonin production, which limits the available tryptophan for niacin synthesis

Question 24

Clinical features of vit C deficiency

Answer 24

Scurvy:

Hyperkeratosis, coiled corkscrew hairs, 
gingivitis 
mucosal bleeding, 
impaired wound healing, 
arthralgia, swollen joints, 
anaemia (normocytic or macrocytic)