Office of Dietary Supplements - Vitamin E

Introduction

• Vitamin E is naturally found in foods or as a dietary supplement.
• It consists of fat-soluble compounds with antioxidant activities.
• Exists in eight forms: alpha, beta, gamma, delta-tocopherol, and tocotrienol.
• Alpha-tocopherol is the only form meeting human nutritional requirements.
• Liver regulates vitamin E, resecreting only alpha-tocopherol.

Antioxidant Role

• Protects cells from free radicals which may contribute to cardiovascular disease and cancer.
• Limits the production of reactive oxygen species (ROS).
• Involved in immune function, gene expression regulation, and metabolic processes.
• Enhances function of blood vessels, inhibiting platelet aggregation.

Recommended Intakes

• Dietary Reference Intakes (DRIs) guide nutrient intakes.
• Various age and gender-specific recommendations.
• Key metric: Recommended Dietary Allowance (RDA) for alpha-tocopherol.
• Conversion between mg and International Units (IU) provided.

Sources of Vitamin E

Food Sources

• Nuts, seeds, vegetable oils, green leafy vegetables, and fortified cereals.
• Common forms include gamma-tocopherol found in vegetable oils.

Supplements

• Often provide alpha-tocopherol, though others exist.
• Synthetic versions have different activity levels compared to natural forms.

Vitamin E Intakes and Status

• Surveys show American diets often provide less than RDA levels.
• Low-fat diets may not meet vitamin E needs without careful food choices.

Vitamin E Deficiency

• Rare, but risk factors include fat-malabsorption disorders and low birth weight in infants.
• Deficiency can cause neuropathy, ataxia, muscle weakness, and immune issues.

Vitamin E and Health

Heart Disease

• Studies show mixed results; some suggest lower heart disease rates with higher intakes.
• Clinical trials have not consistently shown benefits in preventing coronary heart disease.

Cancer

• Antioxidant role could theoretically reduce cancer risks, but studies have mixed results.
• Some associations with reduced prostate and colon cancer; however, high doses may increase prostate cancer risk.

Eye Disorders

• Potential role in reducing risk of age-related macular degeneration (AMD) and cataracts.
• Evidence is inconsistent regarding the preventive effects of vitamin E.

Cognitive Decline

• Some evidence suggests benefits in Alzheimer’s patients; however, results are generally mixed.

Health Risks from Excessive Vitamin E

• High doses of supplements can cause hemorrhage and stroke risk.
• Tolerable Upper Intake Levels (ULs) established to prevent adverse effects.

Interactions with Medications

Anticoagulant and Antiplatelet Medications

• High doses may increase bleeding risk when combined with these medications.

Chemotherapy and Radiotherapy

• Antioxidants might reduce effectiveness; consultation with healthcare providers is recommended.

Vitamin E and Healthful Diets

• Emphasis on obtaining nutrients from food sources as per the Dietary Guidelines for Americans.

Disclaimer

• Fact sheet is informational and should not replace medical advice.