Most Americans do not get enough vitamin E in their diet, according to new studies. This critical vitamin supports vision, brain health, immunity and even developing fetuses. One study found that vitamin E deficiency is linked to a greater risk of miscarriage, especially among poor women. And yet around 90% of U.S. adult diets don’t contain adequate amounts of vitamin E, says Axios.

Research has also shown that this fat-soluble vitamin helps boost the immune system so that it can fight off bacteria and viruses. It helps to widen blood vessels and keep blood from clotting. In addition, the National Institutes of Health says that cells use vitamin E to interact with each other and to carry out many important functions.

According to Axios, vitamin E functions as a major antioxidant that protects our cells from oxidative damage. The damage is caused by free radicals, which are molecules produced when your body breaks down food or is exposed to tobacco smoke and radiation, says the Mayo Clinic.

The consequences of oxidative damage — unchecked by vitamin E — include accelerated aging, deterioration of vision and a higher risk of diseases such as cancer, diabetes, and Alzheimer’s. Vitamin E deficiency can cause nerve pain or neuropathy.

If you take vitamin E for its antioxidant properties, keep in mind that the supplements might not offer the same benefits as naturally occurring vitamin E found in food.

Foods rich in vitamin E include canola oil, olive oil, margarine, almonds, and peanuts. You can also get vitamin E from meats, dairy, leafy greens, and fortified cereals.

Vitamin E is available as an oral supplement in capsules or drops, according to the Mayo Clinic. The recommended daily amount for adults is 15 milligrams daily. Women who are lactating need slightly more, at 19 milligrams a day, says the Harvard School of Public Health. Axios notes that you can also use multivitamins fortified with vitamin E and should take these with a meal.

Healthline has a comprehensive list of the best vitamin E supplements. Experts warn that vitamin E can be toxic at very high amounts, so the daily cap is 1,000 milligrams. The supplements can also interact with some treatment and medications, including chemotherapy and anti-coagulants, so always consult with your healthcare provider before taking vitamin E.