Vitamins
Vitamins are an essential part of a well-balanced diet. A basic working knowledge of the main vitamins and minerals used by the human body is useful for therapists and practitioners of a wide variety of treatments / therapies.
Definitions:
Vitamin |
Any chemical within the group of organic compounds required (in very small amounts) by the body in order to maintain good health. These cannot be synthesized by the body and so are essential constituents of the diet - though most can also be taken in tablet form, as dietary supplements.
Deficiencies, and in many cases also excessive intake, of these substances can lead to specific diseases.
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Oil Soluble Vitamins |
Vitamins that are soluble in oil. This group are sometimes described as 'fat-soluble' rather than 'oil soluble'.
This group includes vitamin A, vitamin D, vitamin E, and vitamin K. |
Water Soluble Vitamins |
Vitamins that are soluble in water.
This group includes vitamin C and the vitamin B complex.
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The following table includes basic information about each of the major vitamins.
Summary Table
Signs of Excessive Intake
Signs of Deficiencies
Sources
Functions
Vitamin |
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
Signs of Excessive Intake
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.
Signs of Excessive Intake
Excessive doses (possibly by injection) may lead to toxic symptoms such as:
- Allergic reactions
- Disturbance of heart beat
- Nervousness
- Shaking & Swellings
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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
Signs of Excessive Intake
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
Signs of Excessive Intake
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.
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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
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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:
Signs of Excessive Intake
- Sudden high intake of vitamin C can cause diarrhoea.
- Very high dosage can lead to stomach problems in some people.
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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.
Signs of Excessive Intake
- 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.
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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
Signs of Excessive Intake
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, needed for blood clotting.
- Fish
- Green leafy vegetables
- Meat
- Molasses
- Nuts
- Seaweed
- Also synthesized by bacteria in the large intestines.
Deficiency can lead to osteoporosis.
Signs of Excessive Intake
Some people who have liver diseases cannot tolerate supplements of vitamin K. |
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See also information about minerals (diet & nutrition), amino acids, dietary fibre and water intake in diet.
More about Nutrition