(1)Fat soluble Vitamins (A, D, E, & K)
a) Vitamins A (Retinol)
This is a yellow fat soluble alcohol. It’s sometimes known as the Ant-xorophalmic as deficiency may cause xorophthalmia (severe eye lesion), a disease which causes the lining membranes of the body e.g. the nose, throats and eyes dry up resulting eventually in complete blindness (keratomalacia).
Function of Vitamin A
- It is necessary for healthy skin glands and moist membrane linings of the body including cornea of the eye and bronchiole tubes
- It regulates growth especially in children. It’s necessary for the general health of the eyes but especially the ability of the eyes to adapt to dim light. Retinol contributes to the formation of the pigment Rhodopsin in the retina of the eye which is sensitive to dim light.
- Helps in formation of strong teeth and bones
- Keeps the mucus membranes healthy and the moist surface of the eyes and the nose
- Aids in quick healing of wounds
Sources of Vitamin A
- Carrots
- Meat
- Kidney
-Cheese
- Milk
- Ghee
- Fish
- Oils (cod liver oil)
- Liver (halibut liver oil)
- Margarine
- Butter
- Eggs
Effects of deficiency
- Dryness of the skin and lining membranes leading eventually to xeropthalmia
- There is retarded growth in children
- Night blindness or inability to see in dim light
- Lowered resistance to infection
NB Excess consumption can result to hypervitaminosis which could result to dangers symptomized by nausea, loss of hair and enlargement of the liver.
b) Vitamin D (Calciferol)
Vitamin D can be obtained by the body in two ways:-
a) Directly from food
b) By the action of sunlight on the skin
It is a white crystalline steroid (fatty substance) and can occur as cholecalciferol or ergcalciferol
Functions of Vitamins
- Vitamin D together with calcium and phosphorous, is essential in the formation of bones and teeth
- It is vital importance during pregnancy and childhood as it controls the calafication of laying down of calcium in children’s bones
- It assists in absorption and distribution of calcium in the body
- Aids in children growth
- Prevents rickets in children and oestomalacia in adults
Effects of deficiency
- Rickets in children
- Oestomalacia which is similar to rickets which occurs in adults
- Dental decay
- Poor teeth developments
NB Commercial vitamin preparations taken in excess in conjunction with the diet may result into large deposits of calcium in the blood and heart which can be dangerous in elderly people but it’s very rare
Sources of Vitamin D
- Sunlight reacting on the skin
- Direct sources include:-egg yolk, margarine, oil fish, fish liver oil, dairy products
c) Vitamin E (Tocopherols)
- Although not always regarded as a true vitamin, it is known to be concerned with metabolism
- It belongs to a group of oily substances called tocopherols.
Functions of Vitamin E
- It’s essential for normal metabolism.
- It is very useful anti-oxidant at tocopherols themselves oxidizes very fast delaying normal oxidative and rancidity in food and in the body.
- Aids in muscular activities especially heart muscles.
NB: There is no known effect of its deficiency.
Sources of Vitamin E
- Vegetables
- Cereal products
- Eggs
- Wheat jam
- Soya beans
- Liver
- Pulse vegetables
d) Vitamin K (Koagulation vitamins)
This was discovered by Copenhagen and gets it is initial name from Danish word for clotting which is its main function. It is sometimes called Anti-hemorrhagenic vitamin.
Functions
It assists in the formation of prothrombin, a protein essential for normal blood clotting
Effects of deficiency
The inability of blood to clot well which after accidents or operations may be dangerous
Sources
- Liver (especially pigs liver)
- Green vegetables like spinach and cabbage
- Fish
- Eggs
- Milk
- Some fruits and cereals manufactured by a bacteria present in the intestines
A good mixed diet supplies adequate amounts but extra would be required after loss of blood as in case of haemorrhaging of surgery.
(2) Water Soluble Vitamins
a) Vitamin C
This vitamin is often called the anti-scurvy vitamin
It is the most unstable of all vitamins and is therefore easily destroyed. As it cannot be stored for long in the body, it is important to have daily intake.
Functions of Vitamin C
- It is necessary for health tissue, skin, gums bones and teeth
- It strengthens the blood vessels thus helping to heal wounds and prevent bruising (removal of small layers of skin by a foreign body)
- It prevents scurvy
- It helps to prevent infections. Large amounts of Vitamin C are said to reduce incidents of cases of cold and influenza
- It is necessary for the absorption of iron
- It is involved in metabolism (energy release) and in the functioning of the adrenal gland
Effects of deficiency
- Disease of the skin, gums and teeth
- Delayed healing of wounds and excessive bruising
- Gradual deterioration of health leading to serious cases of scurvy
- Retarded growth
- Susceptibility to infection
- Incomplete absorption of iron leading to anaemia
- Tiredness and irritability.
Sources of vitamin C
- Most fruits and vegetables e.g. citrus (oranges and lemons), tangerines, strawberries, tomatoes, goose berries, guavas etc
- Vegetable sources (best):- peppers, parsley, broccoli, brussel sprouts, green leafy vegetables like cabbages, dodo (amaranthus), cassava leaves, pumpkin leaves etc
NB Vitamin C is the most unstable of the vitamins and therefore liable to be lacking in the diet. Great care should be taken in the purchase, preparation and cooking of foods rich in vitamin C to see that losses are minimized
b )Vitamin B Group
-Vitamin B1 (Thiamine)
This is the most complex vitamin which is likely to be deficient in the diet because it is unstable to heat and water soluble
It is not stored in the body it should be included daily in the diet
Functions of thiamine
- It is concerned with the release of energy from glucose
- It is necessary for growth, good appetite and general health
- It is necessary for health nerves thus preventing the nervous disease called beriberi
Effects of deficiency
- In mild cases, a feeling of being run down, tiredness, loss of appetite and constipation
- Retarded growth in children
- Neuritis and other nervous system diseases and in sever cases beriberi, a nervous disease common in rice eating countries
Thiamine sources
- Plentiful in wheat jam
- Cereals i.e. fortified breakfast cereals
- Yeast
- Pork
- Bacon
- Beef
- Flour if fortified
Vitamin B2 (Riboflavin)
This is a yellow water soluble solid
Functions of vitamin B2
- It is the essential link in the process of cellular respiration by which energy is released from food
- Ensures healthy eyes and skin
Riboflavin is:
1. Part of several co-enzymes which are essential for the release of energy from
carbohydrates, amino acids and fatty acids within the cells.
2. Needed during the conversion of amino acid tryptophan to the vitamin
niacin.
3. Aids in the conversion of folacin into co-enzymes which aid DNA synthesis
and as such has an indirect effect on cell division and growth.
4. Needed in the production of hormones in adrenal cortex.
5. Used in the formation of RBC in the bone marrow
6. Synthesis of glycogen (glycogenesis)
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Titany answered the question on October 6, 2021 at 06:38