The key to a healthy vegetarian diet — like any diet — is to enjoy a variety of foods. No single food can provide all the nutrients your body needs. The more restrictive your diet is, the more challenging it can be to get all the nutrients you need.
A vegan diet, for example, eliminates natural food sources of vitamin B-12, as well as milk products, which are good sources of calcium.
With a little planning, however, you can be sure that your diet includes everything your body needs. Pay special attention to the following nutrients:
Calcium helps build and maintain strong teeth and bones. Milk and dairy foods are highest in calcium. However, dark green vegetables, such as turnip and collard greens, kale and broccoli, are good plant sources when eaten in sufficient quantities.
Calcium-enriched and fortified products, including juices, cereals, soy milk, soy yogurt and tofu, are other options.
Iodine is a component in thyroid hormones, which help regulate metabolism, growth and function of key organs. Vegans may not get enough iodine and be at risk of deficiency and possibly even a goiter. In addition, foods such as soybeans, cruciferous vegetables and sweet potatoes may promote a goiter. However, just 1/4 teaspoon of iodized salt provides a significant amount of iodine.

Iron is a crucial component of red blood cells. Dried beans and peas, lentils, enriched cereals, whole-grain products, dark leafy green vegetables and dried fruit are good sources of iron. Because iron isn't as easily absorbed from plant sources, the recommended intake of iron for vegetarians is almost double that recommended for nonvegetarians. To help your body absorb iron, eat foods rich in vitamin C, such as strawberries, citrus fruits, tomatoes, cabbage and broccoli, at the same time as you're eating iron-containing foods.
Omega-3 fatty acids are important for heart health. Diets that do not include fish and eggs are generally low in active forms of omega-3 fatty acids. Canola oil, soy oil, walnuts, ground flaxseed and soybeans are good sources of essential fatty acids. However, because conversion of plant-based omega-3 to the types used by humans is inefficient, you may want to consider fortified products or supplements, or both.
Protein helps maintain healthy skin, bones, muscles and organs. Eggs and dairy products are good sources, and you don't need to eat large amounts to meet your protein needs. You can also get sufficient protein from plant-based foods if you eat a variety of them throughout the day. Plant sources include soy products and meat substitutes, legumes, lentils, nuts, seeds and whole grains.