Diseases & Conditions


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Vitamin E (Tocopherol)


Vitamin E (tocopherol) is an antioxidant: It protects cells against damage by free radicals, which are by-products of normal cell activity that participate in chemical reactions. Some of these reactions can be harmful. Many people take vitamin E supplements to help prevent certain disorders. Vitamin E supplements do not protect against heart and blood vessel disorders. Whether they protect against Alzheimer's disease, tardive dyskinesia (repetitive involuntary movements of the mouth, tongue, arms, or legs), and prostate cancer among smokers is controversial.

Vitamin E Deficiency

The deficiency may cause impaired reflexes and coordination, difficulty walking, and weak muscles. Premature infants with the deficiency may develop a serious form of anemia. The diagnosis is based on symptoms and results of a physical examination. Taking vitamin E supplements corrects the deficiency.

A very low fat diet lacks vitamin E because vegetable oils are the main source of this vitamin. Disorders that impair fat absorption can also reduce the absorption of vitamin E and increase the risk of vitamin E deficiency. Newborns have a relatively low reserve of vitamin E because only small amounts of vitamin E cross the placenta. Thus, newborns are at increased risk of a vitamin E deficiency. Adults have large amounts of vitamin E stored in fat tissue. In the United States and other developed countries, vitamin E deficiency is rare among older children and adults.

Symptoms, Diagnosis, and Treatment

Symptoms may include slow reflexes, difficulty walking, loss of coordination, loss of position sense (knowing where the limbs are without looking at them), and muscle weakness. Vitamin E deficiency can cause a form of anemia in which red blood cells rupture (hemolytic anemia). Premature infants who have a vitamin E deficiency are at risk of this serious disorder. In premature infants, bleeding (hemorrhage) may occur within the brain, and blood vessels in the eyes may grow abnormally (a disorder called retinopathy of prematurity—see Problems in Newborns: Retinopathy of Prematurity ). Affected newborns also have weak muscles.

Diagnosis is based on symptoms, the presence of conditions that increase risk, and results of a physical examination. Blood tests to measure the level of vitamin E are not readily available.

Treatment involves taking vitamin E supplements by mouth. Premature newborns may be given supplements to prevent disorders from developing. Most full-term newborns do not need supplements because they get enough vitamin E in breast milk or commercial formulas.

Did You Know...

A very low fat diet may be low in vitamin E.

Vitamin E Excess

Many adults take relatively large amounts of vitamin E for months to years without any apparent harm. However, high doses of vitamin E may increase the risk of bleeding (including bleeding within the brain, causing stroke), particularly for adults who are also taking an anticoagulant (especially warfarin Some Trade Names COUMADIN ). Occasionally, adults who take very high doses develop muscle weakness, fatigue, nausea, and diarrhea.

The diagnosis is based on the person's history of using vitamin E supplements and symptoms.

Treatment involves stopping vitamin E supplements. If necessary, vitamin K, which helps blood clot, is given to stop bleeding.

Last full review/revision August 2007 by Larry E. Johnson, MD, PhD

Source: The Merck Manual Home Edition