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Vitamin E (Tocopherol)

Vitamin E (Tocopherol) Functions

Vitamin E is a fat-soluble vitamin, an essential nutrient, which acts as an antioxidant in the human body [1].

Several forms of vitamin E exist: alpha-, beta-, gamma- and delta-tocopherol and -tocotrienol, from which only alpha-tocopherol has a known active function in the human body [1].

Vitamin E or tocopherol has got its name from the Greek toko = childbirth + pher(ein) = to carry; meaning “to carry a pregnancy”, because it was first isolated from a dietary fertility factor in rats [2].

Recommended Daily Intake

The Recommended Dietary Allowance (RDA) for vitamin E for adults, including pregnant women, is 15 mg (22.4 IU) per day, and during breastfeeding 19 mg (28.4 IU) per day [1].

Foods High in Vitamin E

  • PLANT FOODS: sunflower seeds, wheat germ, almonds, hazelnuts, peanuts, vegetable oils, dark green leafy vegetables, taro, sweet potato, pumpkin, avocado, kiwifruit, fortified ready-to-eat cereals, nutrition bars, margarines, peanut butter and beverages
  • ANIMAL FOODS: oily fish (sardines, salmon, herring, trout, mackerel), mollusks (abalone, conch, snails), shrimps.
  • Human breast milk contains about 1 mg vitamin E/liter [3]. The Adequate Intake (AI) for vitamin E for 0-6 month old infants is 4 mg/day and for 7-12 month old infants 5 mg/day, but vitamin E supplements are not recommended [1].

Absorption

Vitamin E is absorbed in the small intestine but only in the presence of fats from foods and bile and pancreatic enzymes required for absorption of fats [1].

Vitamin E Deficiency: Causes, Symptoms

Vitamin E deficiency is rare and healthy people with low dietary vitamin E intake are not likely to develop it. Deficiency may occur in [1]:

  • Premature infants with low birth weight
  • Infants fed by unfortified formula
  • In fat malabsorption caused by pancreatic, liver, gallbladder or bile duct disease, celiac disease, Crohn’s disease, cystic fibrosis
  • Small intestinal bacterial overgrowth (SIBO) [4]
  • Weight loss surgery [5]
  • Rare genetic diseases abetalipoproteinemia, and ataxia and vitamin E deficiency (AVED)

Symptoms of vitamin E deficiency include impaired balance, abnormal sensations, muscle weakness and vision problems due to damage to the retina – retinitis pigmentosa [1].

Vitamin E Supplements

Oral supplements without prescription (over-the-counter):

  • Natural vitamin E is labeled as d-alpha-tocopherol. It contains RRR-alpha-tocopherol.
  • Synthetic vitamin E is labeled as dl-alpha-tocopherol. It contains vitamin E acetate, succinate or phosphate. Synthetic vitamin E from supplements and fortified foods has only 50% of activity of natural vitamin E [6].
  • Vitamin E (alpha-tocopherol) as part of multivitamins
  • Other forms of vitamin E, such as gamma-tocopherol and tocotrienols are also on the market; there  effectiveness has not been well studied yet. It is not yet known if any of synthetic vitamin E forms is more active than other.

By prescription:

  • Alpha-tocopherol as an intramuscular injection
  • Alpha-tocopherol as a dermal patch

Possible Vitamin E Supplements Benefits

There is CONVINCING EVIDENCE  that vitamin E supplements are effective in:

  • Prevention and treatment of vitamin E deficiency [7]

There is INSUFFICIENT EVIDENCE about vitamin E effectiveness in prevention or treatment of acne, age-related macular degeneration (AMD), aging skin, allergic rhinitis or other allergies, altitude sickness, amyotrophic lateral sclerosis (ALS), anemia, asthma, bee stings, benign prostate hyperplasia, blood clots, brain bleeding in premature infants, breast inflammation (mastitis), bronchopulmonary dysplasia in premature infants, bursitis, cancer (bladder, breast, colon, gastric, lung, prostate), cataracts, celiac disease, chest pan in heart disease (angina pectoris), chronic fatigue syndrome (CFS), chronic pancreatitis, common cold or other respiratory infections, Crohn’s disease, coronary heart disease, cystic fibrosis, G6PD deficiency, dementia (Alzheimer’s disease), diabetes mellitus type 2, Duchenne muscular dystrophy, dyspraxia, eczema, frostbite, glomerulosclerosis (kidney disease), hair loss, liver inflammation (hepatitis), high blood pressure in pregnancy (pre-eclampsia), high cholesterol, hot flashes related to breast cancer, H. pylori infection,  Huntington’s chorea, inflammation of the eye uvea (uveitis), impotence, involuntary movements (tardive dyskinesia), labor pain, leg cramps, leg pain due to atherosclerosis in the leg arteries (intermittent claudication), male infertility, miscarriage, myotonic dystrophy, nonalcoholic fatty liver, oral leukoplakia, osteoarthritis, painful menstruation (dysmenorrhea), Parkinson’s disease, peptic ulcers, premenstrual syndrome (PMS), porphyria, radiation-induced fibrosis, restless leg syndrome, retinopathy of prematurity [12], rheumatoid arthritis, scars, seizures (epilepsy), side effects of amiodarone, chemotherapy or laser eye surgery, stroke, sunburn, transplant rejection, ulcerative colitis, venous thromboembolism, or in improving immunity, muscle strength, energy or exercise recovery [7].

Vitamin E is possibly ineffective in anemia of any kind, cancer, heart disease, asthma, osteoarthritis, rheumatoid arthritis, Peyrone’s disease, retinitis pigmentosa, scar prevention after surgery and stroke [7].

Vitamin E Supplements Safety: Side Effects, Toxicity

The Tolerable Upper Intake Level (UL)–the amount that should not cause side effects–for vitamin E for adults (also during pregnancy and breastfeeding) is 1,000 mg (1,500 IU)/day [1].

Possible vitamin E side effects include nausea, diarrhea, stomach cramps, fatigue, headache, blurred vision and rash [13].

Toxic effects of vitamin E has not been observed so far [10].

Possible complications:

  • Long-term vitamin E intake may increase the risk of brain bleeding (hemorrhagic stroke) [1].
  • Vitamin E may may worsen bleeding disorders [13] and retinitis pigmentosa [9].
  • Vitamin E may increase the risk of bleeding during surgery, so stop taking vitamin E supplements at least two weeks before scheduled surgery [13].

During Pregnancy

Vitamin E in doses within Recommended Dietary Allowance (RDA) is safe to use during pregnancy and breastfeeding (pregnancy category A) [11]. In doses greater than RDA, vitamin is pregnancy category C drug, which means harmful effects for the fetuses have not been observed but cannot be excluded because insufficient studies have been done [8].

Vitamin E Interactions With Drugs

Individuals taking blood thinners or having vitamin K deficiency should not take vitamin E supplements without doctor’s supervision to avoid the risk of hemorrhage [10].

Medications that can lower the absorption of vitamin E include cholestyramine, colestipol, isoniazid, mineral oil, orlistat, sucralfate, olestra. Medications that can lower blood vitamin E levels include phenobarbital, phenytoin and carbamazepine [10].

Vitamin E may increase the effects and side effects of cyclosporin and increase the risk of bruising or bleeding when taken along with drugs aspirin, clopidogrel, diclofenac, dipyridamole, ibuprofen, naproxen, dalteparin, enoxaparin, heparin, warfarin or herbs angelica, asafoetida, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, horse chestnut, meadowsweet, poplar, quassia, red clover, willow [10,14]. Vitamin E may decrease the effect of lovastatin, ketoconazole, itraconazole, fexofenadine, triazolam and other drugs that are broken down by the liver [14].

  1. Vitamin E  National Institutes of Health, Office of Dietary Supplements
  2. Tocopherol  Bioetymology.blogspot.com
  3. List of foods high in Vitamin E  US Department of Agriculture
  4. Sachdev AH et al, 2013, Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance  PubMed Central
  5. Lim RTC RB et al, 2010, Benchmarking Best Practices in Weight Loss Surgery  PubMed Central
  6. Vitamin Toxicity  Emedicine
  7. Vitamin E evidence  Mayo Clinic
  8. Vitamin e Pregnancy and Breastfeeding Warnings  Drugs.com
  9. 1993, Treatment of retinitis pigmentosa reported  National Eye Institute
  10. Vitamin E  Linus Pauling Institute
  11. Vitamin E Deficiency Medication  Emedicine
  12. Sapieha P et al, 2010, Retinopathy of prematurity: understanding ischemic retinal vasculopathies at an extreme of life  The Journal of Clinical Investigation
  13. Vitamin E safety  Mayo Clinic
  14. Vitamin E interactions  Mayo Clinic

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