Vitamin E acts as an antioxidant, helping protect the body from free radicals, which are compounds that can damage the body. Vitamin E also supports the immune system and helps make red blood cells.

How Much: Recommended dietary allowance (RDA) = 15 milligrams (mg), or 22.4 international units (IU), for adults.

Too Much: More than 1,000 mg, or 1,500 IU, daily in supplement form may increase bleeding risk, especially when used with aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs).

Too Little: Consumption of too little vitamin E is rare in healthy people. However, people with conditions such as Crohn's disease, cystic fibrosis and liver disease may need extra vitamin E. 

Foods: Vitamin E can be found in healthy vegetable oils, such as canola, almonds, sunflower seeds, peanut butter; spinach, and broccoli.

Interactions:  High amounts may increase bleeding, especially if blood-thinning medications also are used; statins; aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs); and when undergoing chemotherapy or radiation treatments.  

Research Note: Once hailed as a cure-all, vitamin E has been disappointing in studies. Current research has failed to show that it helps prevent cancer, heart disease or arthritis.