Vitamin B

Question 1

The kinds of Vitamin B?

Answer 1

1. ) Hematopoietic: folic acid (B9), B12
2. ) Energy releasing: B1 (Thiamine), B2 (Riboflavin), B3 (niacin), B7 (Biotin), B5 (Panthotenic acid).
3. ) Other: B6 family: pyridoxine, pyridoxal, pyridoxamine.

Question 2

What does vitamin B9 participate in?

Answer 2

Folic acid or folate the fmaily of compounds participate in:

1. ) single carbon transfer reactions (methylation)
2. ) Synthesis of choline, serine, glycine and methionine
3. ) synthesis of purines and pyrimidines

Question 3

Vitamin B9 deficiency in pregnancy?

Answer 3

It is a requirment for dividing cells and requirement with increased blood volume. Also involved with neral tube defects (NTD), low birth weight and premature birth.

Question 4

What is adult megaloblastic anemia?

Answer 4

It is the presence of large cells in bone marrow and due to a defect in nucleic acid synthesis. Symptoms: loss of appetite, diarrhea, and weakness. It can be from deficiency in vitamin B9 or B12. Can’t be distinguished.

Question 5

What is vitamin B12?

Answer 5

Cobalamin - it is a heme ring with a cobalt ion. It is stable with acyano group which is removed when it is in its active form.

Question 6

What does vitamin B12 participate in?

Answer 6

It participates in:

1. ) nucleic acid synthesis
2. ) succinyl-CoA synthesis in FA metabolism
3. ) Methionine metabolism with folate: methionine synthesis and folates recycling

Question 7

How can vitamin B12 be synthesized?

Answer 7

It can only be synthesized by bacteria

Question 8

Sources and RDA of vitmamin B12?

Answer 8

sources - meat, milk, eggs, fish (no vegetal source, so issue for vegan diet)
RDA: 1.8- 2.4 mg per day

Question 9

Neurological manifestations of deficiency

Answer 9

A vitamin B12 deficiency in which an abnormal number of FAs accumulate and they incorporate into cell membranes including neervous system membranes. The symptoms are numbness, loss of balance, confusion, mood distortion and dementia.

Question 10

macrocytic or megaloblastic anemia

Answer 10

Deficiency of B12 like B9, and so b12 is needed to convert folate nto the form which is active for DNA synthesis. It is indistinguishable from the same disease that is seen with folate deficiency.

Question 11

How is vitamin B12 absorbed and transferred?

Answer 11

It is stored in the liver in 3 forms. It has a complex absorption and transport that happens through the interaction of specific proteins.

Absorption: Stomach acid and B12 bind R proteins. Then pancreatic enzymes free B12 to bind intrinsic factor in small intestine. The in the ileum, B-12 intrisic factor is absorbed. B12 synthesized by the microorganisms in the large intestine can not be absorbed.

Question 12

Vitamin B12 deficiency - who can have it?

Answer 12

1. ) Patients with pernicious anemia (autoimmune disorder that results in gastric atrophy and no intrinsic factor).
2. ) people with atrophic gastritis: low or no stomach acid
3. ) people with bariatric surgery
4. ) hypochlorydria due to age
5. ) vegans
6. ) taking high doses of folate supplements can mask b12 deficiency symptoms but may lead to neruological damage.

Question 13

Vitamin B1

Answer 13

Name: Thiamin
Function: Co-enzyme for several multienzyme complexes
Disease due to deficiency: Wernicke’s encephalopathy and beriberi
Symptoms: Mental confusion, ataxia (inability to fine control motor function), ophtalmoplegia (loss of eye coordination)
Food sources: Meat, oatmeal, breakfast cereals, wheat, fortified white flour, milk, eggs, vegetables.

Question 14

Vitamin B2

Answer 14

Name: Riboflavin (FAD/FMN)
Function: component of flavin coenzymes: electron carriers
Disease due to deficiency: glossitis / magenta tongue
Symptoms: lessions of the margin of the lips (cheilosis) and corners of the mouth (anfular stomatitis), inflammation of the tongue, inflammatory skin condition that causes flaky, white to yellowish scales to form on oily areas such as the scalp or inside the ear, lower metabolic rate.
Food sources: offal, eggs, milk, cheese, yeast extracts, dark green leafy vegetables.

Question 15

Vitamin B3

Answer 15

Name: Niacin (NAD/NDAP)
Function: Nicotinamide adenine dinucleotide (NAD) and nicotineamide adenine dinucleotide phosphate (NADP). Involved in electron carrier reactions.
Disease due to deficiency: Glossitis and pellagra
Symptoms: inflammation of the tongue, dermatitis progressed in sun burn like lesions in area exposed to sunlight, diarrhea and dementia.
Food sources: Meat, grains, and vegetables

Question 16

Vitamin B7

Answer 16

Name: Biotin
Function: Co-enzyme involved in carboxylation in lipogenisis and also glucogenisis and catabolism of amino acids.
Disease due to deficiency: rare
Symptoms: dermatitis, glossits and loss of appetite and nausea
Food sources: widely available in food and intestinal flora supply.

Question 17

Vitamin B5

Answer 17

Name: Panthotenic acid
Function: component of Co-enzyme A
Disease due to deficiency: No deficiency or RDA characterised.
Symptoms: n/a
Food sources: synthesized by intestinal flora and widely available such as in eggs, liver and yeast.

Question 18

Vitamin B6

Answer 18

Name: n/a
Function: co enzyme required for transamination reactions
Disease due to deficiency: rare because its stored in muscles
Symptoms: n/a
Food sources: meat, fish, poultry, potatoes, vegetables and fruits.

Question 19

Vitamin C

Answer 19

Name: N/a
Function: antioxidant and co factor for a number of hydroxylation reactions
Disease due to deficiency: scurvy
Symptoms: weakening of CT which result in loose teeth, bleeding gums. Also, delayed healing of wounds due to limited formation of collagen rich scar tissue. Also bruising and haemorrhaging as the vascular system is weakened, Also there is sesceptibility to infection and incomplete iron absorption.
Food sources: citrus, soft fruits, tomatoes and pepper.