Vitamin E constitutes a family of 8 tocopherols and tocotrienol fat soluble compounds. Members of the vitamin E family are hydrophobic fat-soluble compounds found in a variety of food sources such as corn oil, peanuts, vegetable oils, fruits and vegetables consumed through diet. Dietary habits thus play a significant role in which vitamin E isoform is primarily consumed; a Mediterranean diet, for example contains a significant amount of leafy greens, which contain high levels of α-tocopherol. The health benefits of consuming vitamin E through diet or supplementation are believed to be for its antioxidant properties as a peroxyl radical scavenger.

Fat malabsorption as well as metabolic defects can lead to vitamin E deficiency and some dietary intake surveys suggest people, mainly females, do not meet their vitamin E requirements through diet alone.

Liver

Vitamin E has been studied in relation to liver disease. When the liver is diseased and bile salts are unable to reach the intestine for digestion, malabsorption of fat occurs.[1] When fat is not broken down properly, stools become pale, yellow, loose, greasy, foul smelling or frothy and floating –‘steatorrhoea’.[1] As fat contains vitamins, including Vitamin E, patients with liver disease may become deficient in this vitamin.

Patients with non-alcoholic-steatohepatitis (NASH) have been found to have reduced plasma levels of vitamin E.[2]

Vitamin E is an antioxidant that protects against toxic liver injury in animals.[3] It reduces the production of tumour growth factor (TGFβ)[3,4] and reduces the activity of hepatic stellate cells.[5] Vitamin E has already been shown to improve[6] or stabilise[7] hepatic fibrosis scores in NASH.

A trial in hepatitis patients gave those in the active treatment group a daily antioxidant supplementation (vitamin E 800 mg, C 500 mg and zinc 40 mg) for six months. The supplements protected patients against the oxidative effects of the hepatitis C.[8] In 69 hepatitis B patients, serum vitamin E, as well as other antioxidants, was found to be lower in concentration and oxidative stress was found to be higher, than in 20 healthy controls.[9] In a randomised controlled trial, investigators evaluated 51 patients with alcoholic hepatitis. Twenty-five patients received daily supplementation with 1000 mg of vitamin E and 26 took a placebo for three months. Patients showed improvement in serum hyaluronic acid levels.[10]

Age-related cataracts (ARC’s)

A meta-analysis was undertaken to evaluate the relationship between vitamin E and ARC’s. Studies involved samples of people of all ages. Dietary vitamin E intake, dietary and supplemental vitamin E intake, and high serum tocopherol levels were significantly associated with decreased risk of ARC. The risk of ARC decreased with dietary vitamin E intake from 7 mg/d. The findings of the meta-analysis indicated that dietary vitamin E intake, dietary and supplemental vitamin E intake, and high level of serum tocopherol might be significantly associated with reduced ARC risk.[11]

Safety

There is some evidence to suggest that any excess vitamin E may be harmful. Data from recent observational studies raised the concerns of a possible increase in all-cause mortality in patients taking doses of vitamin E higher than 400 IU/d. Moreover a meta-analysis that included 9 trials suggested that vitamin E might increase the risk of hemorrhagic stroke.[12] More recently, an extended follow-up of a large RCT observed a significant increase in prostate cancer incidence in healthy men taking vitamin E 400 IU daily for over 7 years.[13]

References

  1. Grant JP, Chapman G, Russell MK. Malabsorption associated with surgical procedures and it’s treatment. Nutr Clin Pract 1996; 11: 43-52.
  2. Erhardt A., Stahl W., Sies H., Lirussi F., Donner A., Haussinger D. Plasma levels of vitamin E and carotenoids are decreased in patients with nonalcoholic steatohepatitis (NASH) Eur. J. Med. Res. 2011;16:76–78.
  3. Parola M, Leonarduzzi G, Biasi F, Albano E, Biocca ME, Poli G, Dianzani MU. Vitamin E dietary supplementation protects against carbon tetrachloride-induced chronic liver damage and cirrhosis. Hepatology. 1992;16:1014–1021.
  4. Parola M, Muraca R, Dianzani I, Barrera G, Leonarduzzi G, Bendinelli P, Piccoletti R, Poli G. Vitamin E dietary supplementation inhibits transforming growth factor beta 1 gene expression in the rat liver. FEBS Lett. 1992;308:267–270.
  5. Hasegawa T, Yoneda M, Nakamura K, Makino I, Terano A. Plasma transforming growth factor-beta1 level and efficacy of alpha-tocopherol in patients with non-alcoholic steatohepatitis: a pilot study. Aliment Pharmacol Ther. 2001;15:1667–1672.
  6. Harrison SA, Torgerson S, Hayashi P, Ward J, Schenker S. Vitamin E and vitamin C treatment improves fibrosis in patients with nonalcoholic steatohepatitis. Am J Gastroenterol. 2003;98:2485–2490.
  7. Sanyal AJ, Chalasani N, Kowdley KV, McCullough A, Diehl AM, Bass NM, Neuschwander-Tetri BA, Lavine JE, Tonascia J, Unalp A, et al. Pioglitazone, vitamin E, or placebo for nonalcoholic steatohepatitis. N Engl J Med. 2010;362:1675–1685.
  8. Farias MS, Budni P, Ribeiro CM et al. Antioxidant supplementation attenuates oxidative stress in chronic hepatitis C patients. Gastroenterol Hepatol. 2012;35(6):386-94.
  9. Tasdelen Fisgin N, Aydin BK, Sarikaya H, et al. Oxidative stress and antioxidant defense in patients with chronic hepatitis B. Clin Lab. 2012;58(3-4):273-80.
  10. Mezey E, Potter JJ, Rennie-Tankersley L, Caballeria J, Pares A. A randomized placebo controlled trial of vitamin E for alcoholic hepatitis. J Hepatol. 2004;40:40–46.
  11. Zhang Y, Jiang W, Xie Z, Wu W, Zhang D. Vitamin E and risk of age-related cataract: a meta-analysis. Public Health Nutr. 2015 Oct;18(15):2804-14. doi: 10.1017/S1368980014003115. Epub 2015 Jan 16.
  12. Schürks M, Glynn RJ, Rist PM, Tzourio C, Kurth T. Effects of vitamin E on stroke subtypes: meta-analysis of randomised controlled trials. BMJ. 2010;341:c5702.
  13. Klein EA, Thompson IM, Tangen CM, Crowley JJ, Lucia MS, Goodman PJ, Minasian LM, Ford LG, Parnes HL, Gaziano JM, et al. Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT) JAMA. 2011;306:1549–1556.