6 Potential Risks of Taking Too Much Vitamin E

Vitamin E (tocopherol) protects your cells and supports your immune system. You can get what you need from foods like nuts, seeds, and leafy greens. However, taking high-dose vitamin E supplements can cause serious side effects, including an increased risk of bleeding, stroke, and heart failure.

1. Increased risk of bleeding

High doses of vitamin E can increase the risk of bleeding and make it more difficult for blood to clot. This happens because vitamin E interferes with vitamin K (which your body needs for clotting) and keeps your pads to stick correctly. Platelets are blood cells that form clots to stop bleeding.

When your blood can’t clot well, even minor cuts can bleed for longer than normal. In severe cases, this can lead to dangerous internal bleeding.

Signs of excessive bleeding

Call your healthcare professional immediately if you notice:

• Blood in your urine or stools (for example, red or black, tarry stools)
• Confusion, clammy skin, dizziness, weakness or shortness of breath
• Cuts that bleed longer than usual
• Excessive bruising
• Frequent nosebleeds or bleeding gums
• Heavy menstrual periods

Hemorrhagic stroke

In the most severe cases, excessive daily vitamin E supplementation (more than 1,000 milligrams [mg] daily) can cause bleeding inside your brain. This is known as a hemorrhagic stroke and is a medical emergency.

Stroke symptoms usually appear suddenly. Call 911 immediately if you or someone else experiences these symptoms:

• A sudden, severe headache
• Confusion or difficulty speaking
• Numbness or weakness in the face, arm, or leg (especially on one side)
• Difficulty seeing in one or both eyes
• Difficulty walking, dizziness or loss of balance

2. Heart failure

High doses of vitamin E may increase your risk of heart failure, especially if you have heart disease. Heart failure means your heart can’t pump blood as well as it should.

Experts aren’t sure why this happens, but very high levels of vitamin E can actually harm your heart rather than protect it. The risk is higher in people who have recently had a heart attack. In people with heart problems, vitamin E increases the risk of heart failure by 50%.

Warning signs of heart failure

Call your healthcare professional if you notice:

• Confusion
• Lack of appetite
• Persistent cough or wheezing
• Fast or irregular heartbeat
• Shortness of breath
• Sudden weight gain (due to fluid accumulation)
• Swelling of the legs, ankles, or feet
• Unusual fatigue or weakness

3. Risk of prostate cancer

A large study found that healthy men who took 400 international units (IU), or 180 to 268 mg (depending on type), of vitamin E per day for several years had a higher risk of developing prostate cancer.

Experts believe this may happen because high doses of antioxidants, such as vitamin E, can interfere with the body’s natural process of eliminating damaged cells. When these cells are not removed properly, they can grow abnormally and lead to cancer.

4. Drug interactions

Vitamin E may change how certain medications work on your body or increase the risk of serious side effects. Talk to your healthcare professional before taking vitamin E supplements if you are taking:

• Anticoagulants: Increases risk of bleeding when taken with blood thinners like warfarin, Plavix (clopidogrel), or aspirin.
• Cholesterol medications: May reduce the effectiveness of statins like Lipitor (atorvastatin) or Zocor (simvastatin).
• Cancer treatments: May make chemotherapy or radiotherapy less effective.
• Immunosuppressants: May lower blood levels of Neoral or Sandimmune (cyclosporine), a medicine taken after an organ transplant.

5. Weakened immune system

At healthy levels, vitamin E supports important immune cells that help you fight infections. However, very high doses (greater than 1,000 mg per day) can weaken your immune response, making you more likely to get sick or take longer to recover from an infection.

6. Weakened bone health

A high dose of vitamin E may interfere with how your body absorbs other important vitamins, including vitamins A, D, and K. Over time, low levels of these vitamins can weaken your bones and increase your risk of fractures.

Mild to moderate side effects

At high doses, the following mild to moderate side effects may also occur:

• Fatigue (extreme fatigue)
• Muscle weakness
• Stomach upset or diarrhea

How to Take Vitamin E Supplements Safely

Vitamin E supplements may list amounts in international units (IU) or milligrams (mg). Here’s how to convert:

• Natural vitamin E: 1 IU = 0.67 mg
• Synthetic vitamin E: 1 IU = 0.45 mg

For example, 400 IU is 180 mg if synthetic or 268 mg if natural.

The established upper limit for vitamin E supplements is 1,000 mg (1,100 IU synthetic or 1,500 IU natural) per day, but some experts recommend staying below 300 mg per day for long-term use.

If you suffer from certain health conditions, you may experience problems at doses as low as 300 mg per day. Talk to your healthcare professional before taking vitamin E supplements if you have:

• A history of stroke or heart disease
• Bleeding or clotting disorders
• Diabetes

Serious drug interactions are more likely at daily doses of 180 to 268 mg (400 IU) or more.