Vitamin F.
Vitamin F is an outdated term for essential fatty acids (EFA), i.e. fatty acids that cannot be produced by the body and therefore have to be supplied through food.
The following fatty acids are essential for humans:
- Omega-3 fatty acid : α-linolenic acid (alpha-linolenic acid, ALA)
- Omega-6 fatty acid : linoleic acid
Although these fatty acids are essential, they are also mandatory components of the cell membrane . Therefore they have a building block function and are not assigned to the vitamins . In addition, these fatty acids can be metabolized for energy gain.
background
In addition to the gradual breakdown of fatty acids ( β-oxidation ), living beings can also lengthen fatty acids ( fatty acid synthesis ) and introduce double bonds into saturated fatty acids ( desaturase ) and thereby convert them into unsaturated fatty acids.
The liver cells of mammals can convert a single bond up to position 9 of a fatty acid into a double bond. From position 10 to the methyl end of the fatty acid, however, this is no longer possible. It is therefore reserved for plants to convert oleic acid 18: 1 (ω − 9) into linoleic acid 18: 2 (ω − 6) and finally α-linolenic acid 18: 3 (ω − 3).
Biological importance
Mammals need to get the essential fatty acids through food. In this serving linoleic 18: 2 (ω-6) as a precursor for the production of gamma-linolenic acid 18: 3 (ω-6), dihomogammalinolenic acid 20: 3 (ω-6), arachidonic acid 20: 4 (ω-6).
α-Linolenic acid 18: 3 (ω − 3) can be converted into eicosapentaenoic acid (EPA) 20: 5 (ω − 3) and docosahexaenoic acid (DHA) 22: 6 (ω − 3). The fatty acids with 20 carbon atoms serve as precursors for the hormone-like eicosanoids such. B. prostaglandins , thromboxane, leukotrienes, lipoxins, resolvin and eoxin.
Reference income levels
The reference intake values are given by the Panel on Dietetic Products, Nutrition and Allergies of the European Food Safety Authority (EFSA) as follows.
| Common name | Lipid name | Reference revenue value |
|---|---|---|
| α-linolenic acid (ALA) | 18: 3 (ω − 3) | 2 g |
| Linoleic acid (LA) | 18: 2 (ω − 6) | 10 g |
Deficiency symptoms
In the experiment with mice:
- Fat deposits in the liver
- up to twice the amount of liquid required
- infertility
- Dull, dull and disheveled fur with a damp appearance
- flaky skin
- Hair loss on the back, throat and head
- increased scratching
- darker and wrinkled ears
- up to 7-fold thickening of skin layers in the epidermis (7 × stratum Malpighii, 4 × stratum granulosum)
- increased cell division (hyperplasia)
Advertising medium
Linoleic acid is often referred to as "vitamin F" in margarines . Since vitamins have positive connotations, manufacturers try to gain advantages from them.
literature
- Peter Nuhn : Natural Products Chemistry. Microbial, vegetable and animal natural substances. 2nd edition, S. Hirzel Wissenschaftliche Verlagsgesellschaft, Stuttgart 1990, p. 300 ISBN 3-7776-0473-9 .
Individual evidence
- ↑ a b c Klaus Pietrzik, Ines Golly, Dieter Loew: Handbook Vitamins: for prophylaxis, advice and therapy . 1st edition. Elsevier, Urban & FischerVerlag, Munich 2008, ISBN 978-3-437-55361-5 , pp. 458 .
- ↑ David L. Nelson, Michael M. Cox: Lehninger Principles of Biochemistry . 6 ed.WH Freeman, 2012, ISBN 978-1-4292-3414-6 , pp. 842, 845, 359 .
- ↑ European Food Safety Authority (EFSA): Labeling reference intake values for n-3 and n-6 polyunsaturated fatty acids . In: EFSA Journal . 7, No. 7, July 1, 2009, pp. N / a – n / a. doi : 10.2903 / j.efsa.2009.1176 .
- ↑ David N. Menton: The effects of essential fatty acid deficiency on the skin of the mouse . In: American Journal of Anatomy . tape 122 , no. 2 , March 1, 1968, p. 337-355 , doi : 10.1002 / aja.1001220211 .