Micronutrients Flashcards
(16 cards)
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
Are vitamin/mineral supplements required?
Not with a healthy, balanced diet
Causes toxicity
Supplements containing high doses
