Most artificial vitamins made as synthetic substances have the same molecular composition as the natural variant. The synthetic molecules function in the same way as natural molecules, and look the same. There is therefore no difference in efficacy between the vitamins. This does not apply to vitamin E. There are differences in the molecular structure between the two forms that affect how well the vitamin is retained in the body, and to what extent the vitamin is available in the body.

Vitamin E from natural sources is obtained from vegetable oils, mainly soybeans, rapeseed and sunflower oil. This vitamin is naturally known as d-alpha-tocopherol or RRR-alpha-tocopherol. RRR alpha-tocopherol is converted into RRR alpha-tocopherol acetate for greater stability in animal nutrition. Synthetic vitamin E, commonly referred to as dl-alpha-tocopherol or rac-alpha-tocopherol, is a mixture of eight alpha-tocopherol stereo isomers in equal amounts. Only one of these stereo isomers, 12.5% of the total mixture, is RRR or d-alpha-tocopherol – its natural form. The remaining seven stereo isomers have a different molecular composition due to different production processes.

Both natural and synthetic vitamin E is absorbed by the body. After absorption, however, the natural d-alpha-tocopheryl acetate is recognized by RRR-alpha-tocopherol (α-TTP), a transport protein in the liver, and is given priority over synthetic forms.[1][2] The unrecognized synthetic forms of vitamin E end up in the faeces.[3] This separation mechanism allows d-alpha-tocopherol, the natural form, to be retained longer than the synthetic form. The bioavailability ratio (available for use by the body) is about 2:1 for vitamin E from natural sources compared to synthetic vitamin E. [3][4] To compensate, an animal would have to swallow twice the amount of synthetic vitamin E (by weight) to match the bioavailability of the natural variant.

• Human plasma and tissue alpha-tocopherol concentrations in response to supplementation with deuterated natural and synthetic vitamin E. Am J Clin Nutr 1998; 67:669-683.
• Biokinetics of and discrimination between dietary RRR- and SRR-alpha-tocopherols in the male rat. Lipids 1987;22:163-172.
• Absorption, lipoprotein transport and regulation of plasma concentrations of vitamin E in humans. J Lipid Res 1993;34:343-358.
• Relative biological values of d-alpha-tocopheryl acetate and all-rac-alpha tocopheryl acetate in man. Am J Clin Nutr 1980;33:1856-1860.

A number of recent studies have shown significant differences between vitamin E from natural sources and synthetic variants. It has also been shown that natural vitamin E is used more efficiently by the body than synthetic variants. The body therefore has a clear preference for natural sources of vitamin E. Floris only uses the best ingredients. That is why we also use the natural variant of vitamin E in our products. Examples of this are Equisel Pellets and Equi-E Pellets.