Micronutrients Flashcards
What are micronutrients?
Substances required in small amounts for normal metabolism but which cannot be synthesised by the body in sufficient quantities
Vitamins are divided based on solubility: water-soluble + fat-soluble.
Which vitamins are water-soluble + fat-soluble?
Water-soluble = B, C
Fat-soluble = A,D,E,K
What happens if you have a deficiency of:
Vit A?
Vit B12?
Vit C?
Vit D?
Vit K?
A = impaired night vision
B12 = megaloblastic anaemia
C = breakdown of connective tissue
D = impaired Ca absorption + bone mineralisation
K = haemorrhagic disease
The RNI for Vitamin A is _____
Where in the diet is Vit A found?
600 - 700 micrograms/day
Dairy fat, eggs, liver, fatty fish + carotene
Vitamin D is formed in _____ by action of UV light on _______
Vitamin D is a pre-cursor of 1, 25-dihydroxycholecalciferol; this is produced in the ______ regulated by the ______ hormone
Calcitrol acts on nuclear receptors
Stimulates _____ synthesis of Ca2+ binding protein to increase Ca2+ absorption from GIT
Enhances Ca2+ reabsorption from kidney
Where does 90% of our Vit D supply comes from?
Other sources include oily fish, cod liver oil + other fish oils, egg yolk + breakfast cereals
Which type of skin needs more exposure to Vit D?
A deficiency in Vit D can cause ________
Skin
7-dehydrocholesterol
Kidney
Parathyroid
Gene
Ultraviolet B light
Darker skin + elderly
- fair-skinned need 20-30 min of sunlight, 2-3 times a day
Rickets/osteoporosis
The RNI of Vitamin E is _____
Vitamin E is a fat-soluble antioxidant - it prevents damage to ______
Where can you find Vitamin E in the diet?
3-4 mg/day
Phospholipids
Vegetable oils, wholegrain cereals, greenleafed veg, seeds, nuts
The RNI for Vitamin K is _______
Vit K is required for post-transitional modification of _____ + clotting factors VII, IX + X
What drug blocks Vit K reductase?
Where can you find Vit K in diet?
Vitamin K can cause _______ in new borns
1 microgram/kg/day
prothrombin
Warfarin
Liver, green leafy veg, veg oils, milk (interact with warfarin)
Haemorrhage
The RNI for Folic acid is _____
Where can you find folic acid in the diet?
What can a lack of folic acid cause?
A lack of folic acid can be due to poor diet, malabsorption or phenytoin
200 micrograms/day
Green leafy vegetables, liver
Megaloblastic anaemia, neural tube defects
Vitamin B12 + folate pathways are interlinked.
Fill in the gaps
Deficiency affects cells in which there is high turn over of DNA
Give an example of a cell which is affected
What is megaloblastic + pernicuous anaemia?
Red blood cells
Megaloblastic anaemia - large, immature blood cells
Pernicious anaemia - impaired uptake of vit B12
Development of spinal cord
Thiamin (B1) is required for _____
The RNI for Thiamin is _____
Where in the diet is thiamin found?
A lack of thiamin can cause….
Thiamin deficiency can cause a poor metabolism of _____ + accumulation of _____. This is a reduced lipid + myelin biosynthesis.
Metabolism
1mg/day
Foritfied breakfast cereal + flour, milk, vegetables
Beriberi - effects on sensory + motor nerves; motor nerves; paralysis, muscle wasting
Risk is poor diet, alcoholics + refined flour
Carbohydrate
Pyruvate
Nicotinic acid (B3) is required for ______
The RNI for nicotinic acid is _____
Where in the diet can nicotinic acid come from?
A lack of nicotinic acid can cause _____
Metabolism
17mg/day
Sources = meat, cereals, fish
Pellagra - dermatitis, diarrhoea, dementia
The is due to poor diet + alcoholics
The RNI for vitamin C is _______
Where in the diet does Vitamin C come from?
A lack of vitamin C causes ______
A risk of this is due to poor diet
It acts as a antioxidant
It is required for _____
40mg/day
Fruit, salad, + leafy veg
Scurvy (bleeding gums, loose tooth, leaky vessels) due to impaired synthesis of collagen
Proline hydroxylase (converts proline to hydorxyproline for collagen production)
The RNI for Calcium is _____
What foods are rich in calcium?
A lack of calcium can cause ________
A risk of this is due to poor diet
How much calcium does an adult contain?
Calcium is laid down in bones by _____. After ______, calcium balance in bones becomes negative
An example of a disease due to impaired absoption of calcium is ______
Calcium is needed for bones, cell signalling + muscle function
What drug can increase risk of osteoporosis?
This can cause pts to require calcium supplements <1500mg/day + reduced uptake in GI disease e.g. crohn’s
700mg/day
Milk + milk products, fish, green veg
Osteoporosis
1.2kg
early-mid 20s
menopause
coeliac
corticosteroids
The RNI for Iron is _____
The dietary sources of Iron are ______
A lack of Iron can cause ______
An increased risk of this can be due to chronic blood loss + veg diet (low in iron)
Iron has a role in metabolism as it is a component of _____. It stored as _____.
Which iron is better absorbed - haem iron or non-haem iron?
______ aids absorption
______ inhibit absorption
What are the symptoms of the deficiency?
This is the most common micronutrient deficiency
8.7 mg/day in males; 14.7 mg/day in females
Meat, fish, cereals, green veg etc
Anaemia
Haemoglobin, myoglobin, enzymes
Ferritin
Haem iron
Vitamin C
Calcium + tea
Anaemia = fatigue, restlessness, impaired performance
