Selenium is a trace element that functions as an antioxidant in the enzyme glutathione peroxidase. This important enzyme is present in all cells and helps neutralize the free radicals - unstable oxygen molecules - produced by normal cellular processes. Selenium is also needed for the proper functioning of the thyroid gland and may play a role in fertility, especially in men. Research also suggests that selenium may reduce the risk of lung, liver and prostate cancers. Inadequate selenium has also been associated with impaired immune function. Top sources of selenium include Brazil nuts, fish, whole grains, wheat germ, and sunflower seeds. The amount of selenium in vegetables is dependent on the selenium content of the soil.

Studies have shown that adding soy to a diet low in saturated fat and cholesterol may help reduce your risk of heart disease. According to The American Heart Association, 25 grams of soy protein per day is needed to show significant cholesterol-lowering effects. One-half cup (128g) of raw soybeans has 188 calories and provides an excellent source of protein, fiber, calcium, iron, magnesium, potassium, manganese, vitamin C, thiamin, and folate, as well as a good source of riboflavin, and niacin. In addition, studies show soy isoflavones such as genistein may help prevent and treat prostate cancer and may reduce breast cancer risk. Soy is versatile as it comes in many different liquid and solid forms, including such foods as soymilk, soy yogurt, soy cheese, tofu and tempeh, which serve as popular meat substitutes in vegetarian diets.   

Spinach is a Superfood for your heart, with 1 ½ cups raw (85g) providing a top source of heart-healthy nutrients such as folate, potassium, and magnesium, as well as an excellent source of manganese, and vitamins A, C, and K. This same serving also provides a good source of iron and has just 20 calories. In addition, spinach supplies a top source of the eye-healthy carotenoids lutein and zeaxanthin, making spinach a Superfood for your eyes as well. In addition, Popeye's favorite may help maintain mental sharpness and reduce the risk of  cancers of the liver, ovaries, colon and prostate. You get all of this for just 20 calories.

Squash comes in winter (hard skin) and summer (soft skin) varieties. One cup (140g) of winter squash (butternut) has about 60 calories and provides an excellent source of vitamins A and C, as well as a good source of fiber, magnesium, potassium, manganese, and vitamins E and B6. One cup (113g) of raw summer squash (zucchini) is lower in calories (just 18) and provides an excellent source of vitamin C, as well as a good source of vitamin B6. In addition, this summer squash is also much higher in the carotenoid antioxidants, lutein and zeaxanthin, both of which promote eye health.  

Eight medium strawberries (147g) have 45 calories, provide more than 150 percent of the Daily Value of vitamin C, an excellent source of manganese, as well as a good source of fiber. In addition, strawberries are loaded with brain healthy antioxidants, such as anthocyanins and quercetin, making them a Superfood for your brain. No wonder strawberries are the most popular berries in the United States.

This nutrient-rich tuber is often classified as a yam, but they are actually two different vegetables. Sweet potatoes are more commonly found in supermarkets while true yams are imported only on a limited basis. A medium baked sweet potato (114g) contains 103 calories and provides an excellent source of manganese and vitamin C, as well as a good source of potassium, fiber, pantothenic acid, and vitamin B6. This same serving contains over 400 percent of the daily value of vitamin A and more eye-healthy beta-carotene than any other fruit or vegetable, making sweet potatoes a Superfood for your eyes. Other benefits of this mega-dose of vitamin A include healthy skin and hardy immune function. Some research also suggests this powerful antioxidant may prevent cancer both by neutralizing free radicals and by promoting communication between cells. For information about other potato varieties click here.

A medium tangerine (109g) contains 50 calories and provides an excellent source of vitamin C, as well as a good source of fiber. Did you know that among citrus fruits the tangerine is highest in pectin? Studies show this soluble fiber benefits your heart by helping lower blood cholesterol levels. Tangerines also contain more than 170 phytonutrients - including many powerful flavonoids and carotenoids, which in addition to having antioxidant properties, may also have anti-inflammatory and anti-tumor effects. For example, tangerines are a top source of beta-cryptoxanthin, which is linked to lower lung and prostate cancer risk. This carotenoid may also improve joint health. In fact, a recent British study found that people in the top one-third of beta-cryptoxanthin intake were almost half as likely to develop polyarthritis (inflammation that affects at least two or more joint groups) as those in the lowest third.

Tea is virtually calorie-free, contains less caffeine than coffee and provides a top source of  antioxidant polyphenols. Research suggests tea may help lower blood pressure, reduce the risk of diabetes, promote liver health, and support the immune system. Green tea in particular may boost your metabolism and reduce the risk of Alzheimer's and an array of cancers - including lung, prostate and breast cancer. No wonder tea remains the most consumed drink in the world after water, well ahead of coffee, beer, wine and carbonated soft drinks.

The turnip is a fleshy root vegetable related to broccoli, Brussels sprouts, cabbage, and the mustards. Depending on age and variety, turnips can be round or shaped like a top, range in diameter from two inches to over a foot, and weigh up to fifty pounds. The most common type of turnip in Europe and North America is mostly white-skinned except for the upper 1 to 3 centimeters, which protrude above the ground and are purple, red, or green wherever sunlight has fallen. The interior flesh is entirely white and has a slightly sweet, peppery flavor and a crisp texture. One medium turnip (122g) has only 34 calories and is an excellent source of vitamin C. In addition, turnips have significant quantities of cancer fighting glucosinolates, which promote the body's own natural detoxification systems.

One medium tomato (148g) contains only 35 calories and provides an excellent source of vitamin A and vitamin C, as well as a good source of potassium (helps control blood pressure) and vitamin K. Tomatoes are also one of the best sources of lycopene, a potent antioxidant that several studies have shown may reduce the risk of heart disease, making them a Superfood for your heart. This colorful carotenoid may also lower the risk of a range of different cancers, including prostate,   ovarian, cervical, oral, pharyngeal, esophageal, stomach, colorectal, lung and pancreatic cancers. Bonus: Cooking tomatoes will help you maximize these health benefits because it releases lycopene from the cell walls, making it more available to the body.

At first glance, you'd think the awkward-looking Ugli® fruit is the ugly duckling of the citrus family, but peel off the thick, shriveled skin and you'll find a delightfully tart, yet sweet-flavored fruit, mingling flavors of grapefruit, tangerine and orange. The fruit originated in Jamaica , although it is unknown whether it is a crossbreed between grapefruit and tangerine, or grapefruit and orange. Like other citrus fruits, the Ugli® fruit is high in vitamin C and a good source of fiber. In addition, Ugli® fruit supplies antioxidant flavonoids, such as hesperetin and naringenin, which research shows, may reduce the risk of heart disease. (Ugli® is a trademark of Cabel Hall Citrus Limited.)

Most people associate vegetarianism with abstention from meat, but there are actually many variations:
- Pesco-Vegetarian: Eats plant-based foods, dairy and eggs plus fish, but not other types of meat.
- Lacto-Ovo Vegetarian: Eats plant-based foods, dairy and eggs, but not meat.
- Lacto-Vegetarian: Eats plant-based foods and dairy products like cheese and milk, but not eggs or meat.
- Vegan: Eats only plant-based foods, not dairy products, eggs, or meat. Vegetarian diets are generally low in saturated fat and cholesterol. Not surprisingly, research shows vegetarian women weigh less than their carnivorous peers. However, vegetarian diets do run the risk of deficiency in the following nutrients, so make sure to get plenty of the plant sources listed. - Protein: Soy (tofu, tempeh), whole grains, legumes, and nuts.
- Iron: Spinach, broccoli, dried beans, dried fruit, whole grains, fortified cereals, and brewer's yeast.
- Calcium: Arugula, broccoli, kale, soy and legumes.
- B vitamins: Mushrooms, legumes, oats, beans, and green leafy vegetables. However, vitamin B12 is only found in animal or fortified products so it is recommended that all vegetarians monitor their intake of this nutrient. - Zinc: Beans, oats, green peas, fortified cereals, and sunflower seeds.

The 14 essential vitamins can be classified into two groups: fat-soluble and water-soluble. The fat-soluble vitamins include A, D, E and K, and have many functions, including promoting healthy eyes and bones. The water-soluble vitamins include all the B vitamins, choline and vitamin C. Most of these are involved in essential enzyme systems and energy metabolism. Each of the vitamins was discovered, and its requirement determined, by its ability to cure and prevent a particular disease or group of symptoms. So, be sure you eat plenty of vitamin-rich foods such as fruits and vegetables.

Watermelon is a Superfood for your heart, with one serving (1/18 medium melon, 280g) providing an excellent source of vitamins A and C, as well as a top source of lycopene - a potent antioxidant that several studies have shown may reduce the risk of heart disease - for just 80 calories. This colorful carotenoid may also lower the risk of a range of different cancers, including prostate, ovarian, cervical, oral, pharyngeal, esophageal, stomach, colorectal, lung and pancreatic. Bonus: Studies show lycopene may also enhance male fertility, while another watermelon compound, the amino acid citrulline (found mostly in the rind), may function as a natural alternative to Viagra.

While orange sweet potatoes are often sold in your grocery store as a yam, true yams are lighter in color and rarely sold in the U.S., since, among other reasons, they can grow up to 7 feet long and weigh up to 150 pounds. One-cup (136g) of yams has 158 calories and provides a top source of potassium, an excellent source of fiber, vitamin C, and manganese, as well as a good source of vitamin B6 and copper. For information about other tuber varieties click here.

Zeaxanthin is a strong antioxidant and one of two yellow carotenoids (lutein is the other) found in the eye that are believed to filter out harmful blue light and protect against age-related macular degeneration, the leading cause of blindness in people over 65. According to USDA researchers, zeaxanthin intake may also reduce the risk of certain types of cancer, especially of the lung and breast. Leading sources include green leafy vegetables, orange peppers, and corn.

Zinc plays a vital role in maintaining healthy skin - and repairing it when injured. This nutrient also supports immune function, promotes prostate and eye health, and is vital for normal growth, reproduction, taste and smell. Unfortunately, one-third of Americans over 70 years old are zinc deficient. Top sources include oysters, crab, turkey, beans, oats, green peas, and sunflower seeds.

Zucchini is a popular summer squash that can be eaten raw or cooked. One cup (113g) of raw zucchini has just 18 calories and provides an excellent source of vitamin C, as well as a good source of vitamin B6. This low calorie food also supplies a significant quantity of the antioxidant carotenoids lutein and zeaxanthin. This is important because a Harvard study of over 77,000 nurses reported that women (over age 45) who got the most lutein and zeaxanthin through their diets had 22% fewer cataract surgeries.