Selenium is a trace element that is essential for your health in small amounts. Selenium is needed for the function of certain enzymes called selenoproteins, which function as antioxidants, hormone regulators and regulators of protein synthesis. Without proper intake of selenium form your diet, your body cannot make these proteins. Selenium deficiency can cause cardiomyopathy, a type of heart disease, and osteoarthritis. Selenium is mainly found in meat, seafood, grains and nuts. Many vegetables contain small amounts of selenium.

The recommended selenium intake is 20 to 40 mcg for children and 55 mcg for teens and adults per day. Consuming large amounts of selenium can be toxic, however, according to the Linus Pauling Institute. Selenium toxicity can cause brittle and loss of nails and hair, gastrointestinal problems, skin rashes and nervous system abnormalities. The upper intake level for selenium is 90 to 280 mcg for children and 400 mcg for teens and adults.

Few vegetables provide large amounts of selenium. Get around 20 percent -- 11 mcg -- of your daily selenium by eating a cup of spinach, soybeans, lima beans or pinto beans, or 2 cups of asparagus, mushrooms, garbanzo beans or black-eyed peas.

A number of vegetables contain low amounts of selenium. Foods that contain around 10 percent -- 5.5 mcg -- of your daily selenium include 2 cups of white beans or green peas or 2 1/2 cups of broccoli, Brussels sprouts, kidney beans or black beans. Onions, winter squash, kale, carrots and cauliflower also contain low amounts of selenium.

Add vegetables that contain selenium to your regular meals to improve your selenium intake. For example, add mushrooms or spinach to your bean dip; use a variety of beans in your chili; add asparagus, mushroom and onions to pasta sauces; and add spinach, beans and mushrooms to a green salad. The average person gains selenium through a variety of types of foods in their diet. Vegetarians can fulfill the daily intake of selenium -- 55 mcg -- by eating 2 cups of spinach; 1 cup of pinto, lima or soy beans; 2 cups of mushrooms; 1 cup of asparagus; and 2 1/2 cups of broccoli.