Vitamin
|
Functions
|
Sources |
Signs of
Deficiencies |
Signs of
Excessive Intake
|
A
(Retinol)
See also Vitamin A in the news.
|
- Essential for growth
- Vision in dim light
- Maintenance of soft mucous tissue
|
- Milk products
- Egg yolk
- Liver
Can be formed in the body from its precursor (beta-carotene), found in:
- Cabbage
- Carrots
- Green vegetables
- Lettuce
- Orange / yellow vegetables
- Yellow / red fruits.
|
Deficiency can lead to:
|
Early indications of excess vitamin A can include dry skin and itching.
Vitamin A can be stored in the body in such large quantities
that it can become toxic. Symptoms may include: dizziness,
nausea, headaches and vomiting.
|
B1 (Thiamin, Aneurine)
See also Vitamin B in the news.
|
- Formation of the enzyme thiamin pyrophosphate
- Promotes normal metabolism, appetite, digestion, and growth
- Brain development and function.
|
- Beans
- Cereals
- Meat
- Nuts
- Peas
- Potatoes
- Yeast
|
Moderate deficiency can induce anxiety, depression and irritability. Extreme Deficiency can lead to the disease 'Beriberi' - involving nerve inflammation, muscular weakness and, in extreme cases, heart failure.
|
Excessive doses (possibly by injection) may lead to toxic symptoms such as:
- Allergic reactions
- Disturbance of heart beat
- Nervousness
- Shaking & Swellings
|
|
B2
(Riboflavin)
|
- Production of acetylcholine, noradrenalin, serotonin (neurotransmitters essential to the brain)
- Release of energy from carbohydrates
- Synthesis of arachidonic acid, linoleic acid and linolenic acid (essential fatty acids)
- Tissue respiration.
|
- Cheese
- Eggs
- Fish
- Liver
- Milk
- Pulses
|
Deficiency can lead to:
- Ariboflavinosis
- Dizziness
- Eczema
- Insomnia
- Oversensitivity to light
- Scaly Scalp
|
Overdose is unlikely but extremely large doses are associated with numbness and itching.
|
B6
(Pyridoxine)
|
Many functions including:
|
Many foods including:
- Fish
- Green vegetables
- Meat
- Milk
- Liver
- Whole-grain cereals
|
Rare, but can lead to:
- Loss of appetite
- Anaemia
- Fatigue
- Nervousness
- Insomnia
- Memory problems
- Menstrual problems
|
Excessive intake can lead to poisoning and damage to the central and peripheral nervous systems, especially the sense of touch.
|
B9
(Folic Acid)
|
- Synthesis of nucleic acids
- Pre-conception & in early pregnancy folic acid is thought to help prevent neural tube defects and other congenital foetal malformations.
|
- Green leafy vegetables (such as spinach)
- Kidneys
- Liver
- Nuts
- Whole-grains
- Yeast extract
|
- Megaloblastic anaemia (includes several types of anaemia)
- Apathy / Depression
- Dizziness
- Dull grey-looking skin.
|
|
|
B12
(Cyanocobalamin)
|
- Synthesis of nucleic acids
- Maintenance of myelin in the nervous system
- Correct functioning of Folic Acid.
|
- Brewers Yeast
- Dairy products
- Eggs
- Fish
- Liver
- Meat
|
- Affects most body tissues, especially those containing rapidly dividing cells
- Pernicious anaemia
- Degeneration of the nervous system (incl. loss of sensation and poor co-ordination)
- Tongue infections
|
|
C
(Ascorbic Acid)
See also Vitamin C in the news. |
- Antioxidant Properties
- Maintaining healthy connective tissues
- Integrity of cell walls
- Synthesis of collagen
- Improves resistance to infections
- Promotes healthy function of phagocytes (a type of white blood cell)
- Can help to reduce allergic reactions by inhibiting the action of histamine.
|
- Citrus Fruits
- Potatoes
- Vegetables
|
Mild deficiency:
- Tender joints
- Soft / Bleeding gums
- Reduced immunity to diseases
- Weakness
Extreme Deficiency:
|
- Sudden
high intake of vitamin C can cause diarrhoea.
- Very high dosage can lead to stomach problems in some people.
|
D
See also Vitamin D in the news. |
- Absorption of calcium and phosphorous (from the intestine & deposition of them in the bone).
- Regulation of the permeability of cell membranes.
|
- Liver
- Fish oils
- Ergocalciferol (Vitamin D2) from plant sources
- Cholecalciferol (Vitamin D3) is produced by the action of sunlight on
7-dehydrocholesterol, which is in the skin.
|
Deficiency
may be due to poor diet or to insufficient sunlight
and can lead to:
- Decalcified bones
- Rickets (in children)
- Problems in dental development (in children)
- Osteomalacia (in adults)
- Muscle weakness and cramps
- Osteoporosis - if deficiency over extended period of
time.
|
- Over-calcification of the bones and teeth
- Formation of calculus stones in the kidneys and other organs
- Hardening of arteries.
- In cases of extreme over-dose, vitamin D can lead to poisioning. Symptoms may include: General discomfort, itchy eyes and skin, extreme thirst diarrhoea.
|
|
E
(Tocopherols and Tocotrienols)
See also Vitamin E in the news. |
- Antioxidant properties
- Muscle Development
- Production of red blood cells
- Reproductive functions.
|
- Butter
- Corn and peanut oils
- Eggs
- Soya beans
- Vegetable oils
- Wheat germ
- Wholemeal Cereals.
|
|
Some vitamin E can be safely stored in the body but excessive doses can result in stomach problems and diarrhoea.
|
K |
- Formation of prothrombin by the liver - for blood clotting.
|
- Fish
- Green leafy vegetables
- Meat
- Molasses
- Nuts
- Seaweed
- Also synthesized by bacteria in the large intestines.
|
Deficiency can lead to osteoporosis
|
Some people who have liver diseases cannot tolerate supplements of vitamin K.
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