Vitamin E

Ingredient name: dl-Alpha-Tocopheryl Acetate (Vitamin E)

Chemical Formula: C31H52O3

Quantity in one pouch of Soylent: 30 IUs

Institute of Medicine daily recommended intake: 22.4 IUs

Nutrition role

Vitamin E is one of the most effective lipid-soluble antioxidants.[1] The body needs antioxidants to prevent a variety of compounds from undergoing undesired oxidations, which - if left unchecked - can cause significant damage to tissue and cells.

Vitamin E stops lipid peroxidation, which is caused when an unpaired electron (also known as a free radical) starts a chain reaction that can break apart and damage a cell's phospholipid membrane. Vitamin E functions by reacting with the electron (and the oxygen- or nitrogen-based molecule that the "free" electron is associated with) which prevents the destructive chain reaction from taking place in the cell membrane.[2] Some data shows that vitamin E reacts with certain type of free radicals 1,000 times faster than the free radicals would be able to react with polyunsaturated fatty acids (a type of lipid).[3]

Unchecked lipid peroxidation has been linked to atherosclerosis, and inflammation.[4] An adequate supply of vitamin E provides cell membranes throughout the body with a defense mechanism for oxidative reactions.

Absorption mechanism

Vitamin E is extremely hydrophobic (insoluble in water) and as such, its absorption mechanism is similar in many ways to other lipids. Some studies suggest that up to 70 percent of ingested vitamin E is absorbed in the small intestine[5], while others suggest only 50 percent of all consumed vitamin E is absorbed before being excreted.[6][7]

After absorption in the small intestine, vitamin E, along with other lipids, is transferred to the liver via intercellular space and the lymphatic system.[8]

There are four different types of tocopherols. Of these, alpha-tocopherol is the biologically active version and is highly favored by the alpha-tocopherol transport protein for secretion from the liver into the bloodstream, where it is bound to several types of cholesterol-carrying proteins and transported throughout the body. The vast quantity of the remaining three types of tocopherols (beta-, delta- and gamma-tocopherol) are metabolized in the liver and excreted from the body.[9]

Reason this form chosen

Dl-alpha-tocopheryl acetate is the synthetic form of alpha-tocopherol. While this form has a slightly decreased bioavailability from alpha-tocopherol, this can be overcome by an increase in quantity. Please note that the IUs are compound-specific and account for the reduced bioavailability of the synthetic form of vitamin E.

[1]  Burton, Graham W. "Vitamin E: Molecular and Biological Function." Proceedings of the Nutrition Society 53, no. 02 (1994): 253. 

[2] Ibid., 251-252.

[3] Buettner, G.R. "The Pecking Order of Free Radicals and Antioxidants: Lipid Peroxidation, α-Tocopherol, and Ascorbate." Archives of Biochemistry and Biophysics 300, no. 2 (1993): 535-43. 

[4] Manor, D., and S. Morley. "The Alpha-tocopherol Transfer Protein." Vitamins & Hormones 76 (2007): 51. DOI: 10.1016/S0083-6729(07)76003-X

[5] Kayden, Herbert J., and Maret G. Traber. "Absorption, Lipoprotein Transport, and Regulation of Plasma Concentrations of Vitamin E in Humans." Journal of Lipid Research 34 (1993): 344. 

[6] Stipanuk, Martha H., and Marie A. Caudill. "Vitamin E." In Biochemical, Physiological, and Molecular Aspects of Human Nutrition, 671. Third Edition ed. St. Louis: Elsevier, 2013.

[7] Absorption rates are taken into account when Daily Recommended Intake levels are calculated.

[8] Ibid., 671-672.