Vitamin E, which is found in green leafy vegetables, was discovered in 1922 by American researchers Herbert Evans and Katherine Bishop. It was first called “factor X,” when it was found to be required for reproduction in female rats.

The nutrient was later named vitamin E to follow the previously discovered vitamin D.

But vitamin E is not actually one substance. Rather, it is a complex of 10 fat-soluble molecules known as tocopherols and tocotrienols, found in:

• Avocados

• Broccoli

• Grains

• Mangoes

• Nuts

• Oils

• Papayas

• Sweet potatoes

• Tomatoes

It is also found in butter and egg yolks.

The RDA for vitamin E is 15 mg per day, but deficiency is common. The most recent data from the National Health and Nutrition Examination Survey (NHANES) indicates that the average American intake of vitamin E is less than 7 mg per day — not even half the minimum daily requirement.

Vitamin E is a powerful antioxidant that works with other antioxidants such as vitamin C to keep oxidative stress low. It also helps maintain cell membranes by keeping LDL cholesterol from oxidizing.

In addition, optimal vitamin E levels can prevent and treat heart disease, improve diabetes and dementia, and stop cataracts. Vitamin E may also have anticancer properties, though the studies are mixed about this.

When supplementing with vitamin E it is important to avoid synthetic sources, as these can actually impair normal function of the vitamin in the body.

Avoid supplements that contain synthetic vitamin E). It is best to supplement with vitamin E that contains natural D-alpha tocopherol along with mixed tocotrienols.