Micronutrients

Question 1

Vitamins

Answer 1

Humans require adequate amounts of 13 vitamins:
Four fat soluble vitamins (A, D, E, K)
Nine water soluble vitamins, which comprise vitamin C and the eight B vitamins: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), vitamin B6, folate (B9) and vitamin B12

Question 2

Micronutrient deficiency in UK

Answer 2

Generally population is well nourished but…
Concerns about marginalised groups, minority groups, the very young and the very old are associated with:
1) Poor dietary intake
2) Excessive energy dense/nutrient light diets
3) Extreme diets (removal of one or more food groups)

Question 3

Evidence of micronutrient deficiency

Answer 3

There is evidence of iron-deficiency anaemia (as indicated by low haemoglobin levels) and low iron stores (plasma ferritin) in women and older girls.
There is evidence of low vitamin D status in adults and older children, both male and female - has implications for bones (rickets & osteomalacia)
A substantial proportion of adults and older children have functional riboflavin (B2) status values indicative of low status.

Question 4

Micronutrient deficiencies associated with illness

Answer 4

ALD – thiamine (B1), vitamin D
Inflammatory bowel disease – iron, B12, vit D, K, folic acid, selenium, zinc, vit B6 and vitamin B1
Obesity – vit D, copper, zinc

Question 5

Absorption of vitamin B12

Answer 5

B12 combines with protein (R factor) in presence of HCl – in stomach
B12-R complex degraded; free B12 combines with intrinsic factor (IF) – in ileum
B12-IF complex binds with IF receptors in the presence of calcium ions and B12 absorbed into the plasma – in jejunum

Question 6

Vitamin D

Answer 6

Risk factors for vitamin D insufficiency and deficiency
· Pigmented skin (non-white ethnicity)
· Lack of sunlight exposure
· Skin concealing garments or strict sunscreen use
· Multiple, short interval pregnancies
· Elderly or housebound
· Vegan / vegetarian or high phytate consumption such as in chapatis
· Malabsorption (e.g., inflammatory bowel disease, coeliac disease, pancreatic insufficiency)
· Use of anti-convulsants, rifampicin, cholestyramine, anti-retrovirals

Question 7

Iron

Answer 7

Boosts the immune system and wards off infections, bacteria and viruses
Helps produce nerve-signalling neurotransmitters
Is necessary for DNA synthesis
Is used for synthesis of many proteins
Is the oxygen binding site on haemoglobin and myoglobin
Has functional role in all cells
Is a component of cytochrome proteins that produce ATP in mitochondria