What is Vitamin E?
Alpha-tocopherol is a fat-soluble substance commonly known as “Vitamin E.” As it is naturally found in both vegetable oils and animal fats it is rare to find someone with Vitamin E deficiency. Diet alone appears to adequately provide our daily requirement of Vitamin E. Its primary health benefit appears to be related to its antioxidant properties.[1]
Evidence that It Can Be Used To Treat Glaucoma
At least in combination with Vitamin B and DHA, Vitamin E has been shown to improve visual fields and retinal sensitivity in patients with glaucoma.[2]
It may also have a role in preventing bleb failure after trabeculectomy or glaucoma drainage device surgery. In the laboratory Vitamin E has been shown to limit the proliferation of human Tenon’s capsule fibroblasts.[3] These cells are largely responsible for the scarring and failure of blebs. Additionally, Vitamin E was shown to limit bleb failure in rabbit models of trabeculectomy.[4]
Potential Side Effects and Risks:
Vitamin E is well-tolerated with rare side effects in doses up to 1,000 IU per day.[5] However, there is some concern that taking more than 400 IU per day over long periods of time may increase the risk of death.[6]
Potential Drug Interactions
When Vitamin E is taken in doses greater than 400 IU per day it appears to inhibit blood clotting. As such a lower daily dose of Vitamin E is recommended for those who are taking blood thinners. Additionally, it is probably wise to discontinue (or at least reduce the dose of) Vitamin E prior to surgery.
Recommended Dosage
Due to the limited evidence of benefit in patients with glaucoma I do not recommend doses greater than that found in common over-the-counter supplements. In general I recommend limiting Vitamin E supplementation to no more than 400 IU per day.
Where to Buy
Vitamin E can be found in nearly every drug, grocery, or health food store. It’s worth noting that the natural form (d-alpha tocopherol) is better absorbed than the more commonly found synthetic form (dl-alpha tocopherol). As with most supplements, cost can vary widely.
References
1) Jiang Q, Christen S, Shigenaga MK, Ames BN. gamma-tocopherol, the major form of vitamin E in the US diet, deserves more attention. Am J Clin Nutr 2001;74:714-22.
2) Cellini M, Caramazza N, Mangiafi co P, et al. Fatty acid use in glaucomatous optic neuropathy treatment. Acta Ophthalmol Scand . 1998;227(suppl):41–42.
3) Haas AL, Boscoboinik D, Mojon DS, et al. Vitamin E inhibits proliferation of human Tenon’s capsule fi broblasts in vitro. Ophthalmic Res. 1996;28:171–175.
4) Pinilla I, Larrosa JM, Polo V, et al. Alpha-tocopherol derivatives in an experimental model of filtering surgery. Ophth
5) Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/
6) Miller ER 3rd, Pastor-Barriuso R, Dalal D, et al. Meta-analysis: High-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med 2005;142:60520-53.
Lonn E, Bosch J, Yusuf S, et al. HOPE and HOPE-TOO Trial Investigators. Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial. JAMA 2005;293:1338-47.
Bjelakovic G, Nikolova D, Gluud LL, et al. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA 2007;297:842-57.
Hayden KM, Welsh-Bohmer KA, Wengreen HJ, et al; Cache County Investigators. Risk of mortality with vitamin E supplements: the Cache County study. Am L Med 2007;120:180-4.
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