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Introduction to Vitamins
Polish Chemist Casimir Funck coined the term vitamin in
1910 after isolating from rice a substance curing the disorder beriberi.
He called the substance 'vital amine' which then became vitamin.
As other substances were isolated over the following decades the number
of vitamins grew (and shrank, as some vitamins were relegated to 'vitamin-like
substances').
The name of a vitamin is a letter representing a group of chemical compounds
(e.g. vitamin A, vitamin B). A number to distinguish between the various
subgroups of chemicals then follows this letter (e.g. vitamin B12). There
may be a further subdivision, where a lower case letter is added to the
name (e.g. vitamin B12b).
The presence of all vitamins is essential to a healthy physiology. They
perform a variety of vital functions within the body e.g. as cofactors for
enzymatic reactions.
A severe defieciency, or avitaminosis, causes some form of disease. Each
type of vitamin deficiency is associated with its own disease (deficiency
of vitamin D leads to rickets, of vitamin C to scurvy and of vitamin A to
blindness).
Deficiencies also have subtler influences on health the importances of which
have not always been understood. For example UNICEF mentions that vitamin
A is essential for a child's immune system to function properly as it improves
resistance to disease, and is key to improving a child's survival, growth
and development. It then goes on to state - "In the past, vitamin A
deficiency (VAD) has been seen solely as a cause of blindness, and in many
countries, vitamin A activities are still limited to blindness prevention"(6).
As a rule, vitamins cannot be synthesized at all or in large enough quantities
in the human body and must be supplied from the environment through diet.
Just as with carbohydrates, it is possible to construct 'food-chains' for
vitamins, starting with bacteria or yeast.
Vitamins can be said to be associated with various illnesses in 3 ways:
- Problems are caused by a lack of a vitamin (vitamin deficiency or
avitaminosis)
- Problems are caused by an excess of a vitamin (vitamin toxicity or
hypervitaminosis)
- A vitamin is used for therapy (high dosage for a limited time span)
- Other uses - e.g. E300 or vitamin C is used as an antixodant (browning
inhibitor of cut fruit; improving agent for four; meat colour preservative);
E375 or vitamin B3 is used as a colour protector
Just as with other nutrients, when dealing with vitamins the following factors
are important yet often ignored when it comes to determining requirements
(2)-
- bioavailability
- degree with which a substance becomes available to the target
tissue after administration:
- Processing and refining can alter digestibility and absorption
- Other substances may inhibit or enhance processing
- Many people have individual conditions of malabsorption
- inborn errors in metabolism
The term refers to an error in a single gene causing a metabolic pathway
to break down. With regard to vitamins such defects can be -
- an enzyme requiring a specific vitamin in order to function
- a defective absorption of a vitamin
- an inability to transport a vitamin
- an inability to convert a vitamin to its active form
- losses in food processing
covers industrial food processing as well as cooking at home and deals
with losses which are incurred when food is boiled or fried. It should
be noted that some processing techniques can also enhance bioavailability
by destroying vitamin inhibitors.
- vitamin/mineral relationship
vitamins and minerals need each other to complete a function. E.g. vitamin
D is essential for absorption of calcium; calcium is essential for absorption
of B12.
It is common practice to divide vitamins into 2 groups:
- Water soluble
main vitamins are those in group B (e.g. B1, B6). These vitamins are
generally enzyme co-factors and are important for the energy metabolism.
Being water soluble, excess amounts of vitamins can easily be secreted.
A disadvantage with this form of secretion is that the body doesn't
want to or cannot discriminate between the different types of vitamin
B it is secreting. The result is that an excess of one vitamin can cause
a deficiency in other vitamins due to indiscriminate secretion.
- Lipid soluble and insoluble in water
important vitamins in this group are A, D, E, K. They are not generally
enzyme co-factors and they have nothing specifically to do with energy
metabolism.
Because they are insoluble in water these vitamins can be stored in
the body. This means a deficiency only occurs after a considerable period
of deprivation. It also means that it is difficult to get rid of excess
amounts of the vitamins and it is easy for toxic conditions to arise
(5). The only
way to eliminate the vitamins is via the gallbladder.
A table of vitamins and vitamin-like substances
For this article we wanted to produce a simple table of all the vitamins
and vitamin-like substances. This turned out to be a more difficult exercise
than expected, as there seemed to be some disagreement about the more
obscure vitamins. Table 1 lists all the vitamins (past and present) we
could find.
Table 1. A list of Vitamins
| Grouping |
Description |
|
| A |
|
retinol (animal origin), carotin (plant origin)
other names: axerophthol, biosterol, rinyl palmitate, retinyl acetate,
retinal, carotene, carotenoids |
| B |
B1 |
thiamin, thiamine, aneurine |
| |
B2 |
riboflavin, beflavin, lactoflavin |
| |
B3 |
niacin, nicotinic acid, nicotinamide, nicotinate,
pyridine-3-carboxylic acid |
| |
B4 |
Binet: adenine. Mervyn: this is no longer classified
as a vitamin |
| |
B5 |
pantothenic acid |
| |
B6 |
pyridoxine, pyridoxal, pyridoxamine |
| |
B7 |
Binet: either vit I or vit.J. Mervyn: unnamed
vit. For microorganisms |
| |
B8 |
Mervyn: vit. For microorganisms. Binet: biotin.
Mervyn and Geddes: biotin is vitamin H |
| |
B9 |
Nielsen, Binet, Geddes: folic acid, folacin,
pteroyl-L-glutamic acid. Mervyn: unnamed vit. For microorganisms |
| |
B10 |
Binet, Nielsen: para-aminobenzoic acid. Mervyn:
unnamed vit. For chicks. Mervyn, Geddes: paba is vit. Bx |
| |
B11 |
Binet, Geddes: carnitine. Mervyn: unnamed vit.
For chicks. Carnitine is vit.Bt |
| |
B12 |
cobalamin, cobanamide, dibencozide, cyanocobalamine |
| |
B12b |
Geddes: hydroxo-cobalamin |
| |
B12c |
Geddes: nitrito-cobalamin |
| |
B13 |
orotic acid, uracil 6 carboxylic acid |
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B14 |
Binet: xanthopterine (in-soluble in water). Meyer:
derivative of B12 |
| |
B15 |
pangamate, pangamic acid |
| |
(B16) |
No record found (?) |
| |
B17 |
amygdalin, laetrile. Mervyn does not regard this
as a B vitamin |
| |
Bc |
Mervyn: the name for folic acid. Binet: another
name for B9 |
| |
Bt |
Mervyn: the name for carnitine. Binet: another
name for B11. Mervyn also no longer regards carnitine as a vitamin |
| |
Bx |
Mervyn, Geddes:para-aminobenzoic acid (see B10).
Geddes: this is a vitamin-like substance |
| C |
|
ascorbic acid |
| |
C1 |
Binet: ascorbic acid |
| |
C2 |
Binet: same as vit.P |
| D |
|
calciferol |
| |
D1 |
Geddes: steroid alcohols |
| |
D2 |
ergocalciferol, calciferol. Animal source |
| |
D3 |
cholecaliferol. Found in yeast |
| E |
|
tocopherols - alpha, beta, gamma and delta forms |
| F |
|
Binet: linolic acid. Mervyn: no longer a vitamin |
| G |
|
Mervyn, Geddes: B2. Binet: B6 |
| H |
|
Geddes, Mervyn: the name for biotin. Binet: another
name for biotin - see B8 |
| |
H1 |
Binet: B8 (biotin) |
| |
H2 |
Mervyn: procaine; no longer regarded as a vitamin.
Binet: B10 (PABA) |
| |
H' |
Binet: B10 (PABA) |
| I |
|
inositol, bios I, lipotropic factor. Mervyn:
vit.B. Geddes: vitamin-like substance |
| J |
|
choline. Mervyn: vit.B. Geddes: vitamin-like
substance |
| K |
|
quinones |
| |
K1 |
phytomenadione, phyloquinone, phytylmenadione
Can be produced by bacteria in Intestines |
| |
K2 |
menaquine Can be produced by bacteria in Intestines |
| |
K3 |
menadione, menaphtone. Synthetic product |
| L |
L1 |
Binet: same as B9 |
| |
L2 |
Binet: same as B12 |
| M |
|
Binet: stigmasterol |
| N |
|
thioctic acid, lipoic acid. Classified as vit.
N by Binet, Geddes: synthesied by man, used to be a B vit. |
| O |
|
Binet: same as B11 |
| P |
|
bioflavanoids, rutin,citrin,hesperidin. Mervyn:
no longer regarded as a vitamin |
| PP |
|
Mervyn: nicotinic acid. Binet same as B3 |
| T |
|
Mervyn: tegotin /termitin / factor T. Binet:
same as B11 |
| U |
|
Mervyn: anti-ulcer substance. Mervyn: no longer
regarded as a vitamin |
| Vitamin Like substance |
Ubiquinone,
co-enzyme Q, co-enzyme Q10. depends upon vit.E |
|
| Vitamin Like substance |
lecithin, phosphatidylcholine.
Choline (vit.J), inositol (vit.I) form a part of lecithin |
|
Nielsen (1),
Mervyn (2),
Binet (3),
Geddes (4)
References:
- "Biologisk Regeneration" by Kurt Winberg Nielsen, 1981
- "Thorsons Complete Guide to Vitamins and Minerals" by Leonard
Mervyn, 2000
- "Vitamine et Vitaminothérape" by Dr Claude Binet,
1981
- "Vitamins & Minerals", published by Geddes and Grosset,
1999
- "What
are Vitamins" by Betty Walsh , 1995
- UNICEF on vitamin A
Further Reading:
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