vitamins and minerals

Question 1

vitamin B-12

Answer 1

Properties
-Water soluble
-Destroyed by strong acids, alkalis and light
-Heat stable, but some loss during cooking
Food sources
-Meat
-Eggs
-Milk
Other sources
-As vitamin B-12 is found only in animal sources, vegans are strongly advised to take supplements or to consume fortified foods e.g. Soya milk
Biological functions
-Aids the metabolism of fatty acids to release energy
-Aids the metabolism of folic acid
-Maintains the myelin sheath which speeds up nerve impulses
Aids the formation of red blood cells
Effects of deficiency
-Tiredness due to lack of energy
-Increased risk of neutral tube defects in the foetus
-Delayed nerve impulses e.g. memory loss or slow response

Question 2

Vitamin D

Answer 2

Properties
-The most stable of all vitamins
-Fat soluble and insoluble in water
-Heat stable, unaffected by cooking
Food sources
-Oily fish
-Eggs
-Butter
Other sources
-Sunlight-Humans need approximately 20 minuets of sunshine per day
Biological functions
-Control the absorption of calcium and phosphorus into the blood
-Regulates the amount of calcium and phosphorus in bones and teeth helping to maintain density and strength
Effects of deficiency
-Increased risk of bone diseases, such as rickets, osteoporosis and tooth decay
-Increased risk of bone diseases and tooth decay

Question 3

Vitamin A Retinol and Beta-carotene

Answer 3

Properties of Retinol
-Insoluble in water
-Heat stable but affected by high temperatures
-Destroyed by oxygen
Properties of Beta-carotene
-Insoluble in water
-Heat stable but affected by high temperatures
-Unaffected by oxygen

Sources of Retinol
-Eggs
-Milk
-Oily fish
Sources of Beta-carotene
-Carrot
-Leafy green veg
-Tomatoes

Biological functions
-Helps maintain healthy skin and the mucous membrane of the body e.g. the eyes
-Aids growth and development of children
-Helps the eyes adapt to dim light
Effects of deficiency
-Night blindness whereby a person will struggle to see in dim light due to a lack of rhodopsin
-Stunted or delayed growth in childcare leaving them smaller in height from the average of their age

Question 4

Calcium

Answer 4

Calcium is the most plentiful mineral in the body. Approximately 99% of the bones calcium is in the bones and teeth, the remaining 1% is found in the muscles, nerves and blood.
Sources
-Milk
-Cheese
-Yoghurt
Biological functions
-Aids the formation of strong bones and teeth
-Assists blood clotting which is necessary if an injury causes damage to blood vessels
-Aids normal muscle contraction
Effects of deficiency
-Increased risk of bone diseases such as rickets, osteoporosis and tooth decay
-Slow blood clotting of ruptured blood vessels
-Muscles fail to relax after contraction this can cause muscular spasms and cramps
Absorption of calcium
Only 20-30% of calcium intake is absorbed by the body. A variety of factors help and hinder absorption.
Factors that assist calcium absorption
-Vitamin D stimulates the production of calcium-binding protein, assisting absorption
-The hormone oestrogen produced in the ovaries promotes absorption
Factors that hinder calcium absorption
-Tannins present in tea and coffee bind to calcium inhibiting absorption
-Excess dietary fibre binds to calcium inhibiting absorption