Vitamin e

The collective term "vitamin E" refers to a group of compounds consisting of a chromium core and an aliphatic side chain. So far, 8 vitamin active substances of the vitamin E group (alpha-beta-gamma- etc. tocopherol) have been analysed in nature.

The term "tocopherols" (tocopherol from the Greek tocos = birth" and pherein = to bring in) is generally used to describe the different topherol compounds. The tocopherols differ in the number and positions of the methyl groups. The biologically most important tocopherol is alpha-tocopherol. Other naturally occurring tocopherols are 5,7-dimethyltocol and 7-methyltocol as well as tocotrienol and tocomonoenol.

Vitamin E mixtures are a yellow to brown oily liquid found in cereals, nuts, seeds, vegetable oils, milk and eggs. The tocopherols are thermostable but easily oxidizable. They dissolve easily in fatty oils and organic solvents. The vitamin content is measured in i.U. One unit of vitamin E (I.U.) corresponds to 1mg DL-alpha-tocopherol.

Vitamin E is abundant in nature. It is a component of all membranes of animal cells. However, tocopherol is only produced by photosynthetically active organisms such as plants and cyanobacteria.

Especially rich are vegetable oils like:

• Sea buckthorn pulp oil(3304 mg/kg total tocopherol with 1844 mg/kg α-tocophero,
• Wheat germ oil (up to 2435 mg/kg total tocopherol with 70 % α-tocopherol)
• Sunflower oil (454-810 mg/kg total tocopherol with 86-99 % α-tocopherol)
• Palm oil(800 mg/kg total vitamin E, of which 152 are α-tocopherol and 600 mg/kg tocotrienols)
• olive oil (46-224 mg/kg total tocopherol with 89-100 % α-tocopherol).

Vitamin E is also found in numerous vegetables, fatty oils and dairy products. In the animal organism, vitamin E is found mainly in the pituitary gland in the muscles, placenta and breast milk.

Today, vitamin E is mostly produced synthetically as a mixture of the various tocopherols. However, synthetic tocopherol is relatively unstable.

Physiological effects: The biological effects of vitamin E are not yet fully understood. This allows ample unsecured speculation about its biological efficiency. Its antioxidant effect is proven. Tocopherols act as radical scavengers. They are able to protect polyunsaturated fatty acids from oxidative destruction. The human metabolises alpha-tocopherol best. This is due to the high affinity to the alpha-tocopherol transfer protein (alpha-TTP). Vitamin E has functions in the control of the gonads and is therefore also called an antisterility vitamin. An influence of vitamin E on sperm quality has been proven (ElSheikh MG et al. 2015).

Vitamin E requirement: The minimum requirement in infants is about 5 mg/day. For adults, the minimum requirement is about 10 to 25 mg/day. People > 65 years of age tend to require lower amounts than younger adults. The daily requirement for 1-4 year olds is 4-6 mg vitamin E, and for 13-15 year olds 12-14 mg vitamin E (information from the German Nutrition Society).

The recommended daily dosage for an adult (about 15 mg vitamin E) can be achieved, for example, by taking 20 g sunflower oil; alternatively 5 ml wheat germ oil, 30 ml olive oil or 50 g hazelnuts. The plasma level should be above 30 µmol/l.

Vitamin E in Externals: Due to the antioxidant effect of vitamin E (mostly alpha-tocopherol), it is used in many skin care products, mostly to increase product stability. Scientifically doubtful are statements such as: improvement of the skin surface, increase of the moisture content of the skin, slowing down of the aging process. Moreover, vitamin E is said to have a local anti-inflammatory effect and to accelerate the healing of superficial wounds. Vitamin E is also added to sun creams as it is said to have a UV-protective effect (Lin et al 2003).

Tocopherol acetate is used for the local therapy of anular granuloma. Notice! Controversial therapy principle!

Overdosage of vitamin E: An overdose of vitamin E in the normal diet is not possible. Overdoses can occur when long-term supplements with unphysiologically high doses of vitamin E are taken.

Vitamin E deficiency: A vitamin E deficiency is very rarely observed in humans. Unspecific disturbances of muscle and nerve function have been reported (no reliable data available), and symptoms such as dry, wrinkled skin, fatigue and reduced wound healing have been associated.

Vitamin E enhances the effect of anticoagulants. This should be noted when using oral anticoagulants and in cases of vitamin K deficiency.

Vitamin E and dementia: In several large clinical studies, the targeted intake of vitamin E as a food supplement to reduce the risk of dementia did not lead to a positive result. Neither alone nor in combination can the trace element selenium and vitamin E prevent dementia in asymptomatic men (overview in Farina et al 2017).

1. ElSheikh MG et al (2015) Combination of vitamin E and clomiphene citrate in treating patients with idiopathic oligoasthenozoospermia: A prospective, randomized trial. Andrology 3:864-867.
2. Farina N et al (2017) Vitamin E for Alzheimer's dementia and mild cognitive impairment. Cochrane Database Syst Rev1:CD002854.
3. Foote JA et al(2009) Chemoprevention of human actinickeratoses by topical DL-alpha-tocopherol. Cancer Prev Res (Phila) 2:394-400 PubMed Central PMCID: PMC4154592.
4. Lin JY et al (2003) UV photoprotection by combination topical antioxidants vitamin C and vitamin E. J Am Acad Dermatol 48:866-874.
5. Santana AT et al(2015) Mechanisms involved in reproductive damage caused by gossypol in rats and protective effects of vitamin E. Biol Res 48:43.
6. Thomas S et al (2014) Stability, cutaneous delivery, and antioxidant potential of a lipoic acid and α-tocopherol codrug incorporated in microemulsions. J Pharm Sci 103:2530-2538.
7. Wu S et al (2008) IL-8 production and AP-1 transactivation induced by UVA in human keratinocytes: roles of D-alpha-tocopherol. Mol Immunol 45:2288-2296.