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Most vegetarians can get all of the nutrients they require simply by following a well-balanced diet that includes low-fat dairy products, whole grains, vegetables and fruits. However, strict vegetarians – or vegans – who do not consume any animal products face nutritional challenges that can only be addressed by careful dietary planning.

Many people who switch to a vegetarian diet can benefit from consulting a registered dietitian who can help plan a diet that contains adequate levels of all nutrients. This is especially important for women who are pregnant or breastfeeding, others during ages of growth (infancy, childhood and adolescence) and people recovering from an illness.

Nutrients that may not be present in adequate amounts in some vegetarian diets include:

• Calcium. This mineral keeps bones and teeth strong, helps muscles contract, transfers nerve impulses, helps blood to clot, and regulates heartbeat. Vegetarians who consume dairy products should not have to worry about obtaining adequate calcium stores. However, vegans need to plan their diets carefully to obtain this mineral. Many plant foods provide calcium, include broccoli, sunflower seeds, nuts, legumes, some green vegetables (collards, kale, mustard greens), okra, rutabaga, bok choy, dried figs and tortillas. Calcium-fortified foods are good choices as well. These include breakfast cereals, orange juice, and soy or rice beverages.
  
  
• Iron. Obtaining adequate levels of this mineral can be difficult for both vegetarians and non-vegetarians, especially women and children. Iron deficiency can lead to fatigue and iron-deficiency anemia (lack of red blood cells). Plant-based foods contain a version of iron called non-heme iron. Unlike the heme iron found in animal products, non-heme iron is not absorbed as well by the body. To improve absorption of non-heme iron, vegetarians are urged to include a food or beverage rich in vitamin C with every meal. This aids in the absorption of nonheme iron. Cooking with iron pots or skillets also may increase the amount of iron in foods. Finally, semi-vegetarians can boost their iron absorption by eating a little meat, poultry or fish.  Vegetarians are cautioned to avoid drinks with tannin such as tea, when having an iron-containing meal. The tannins can interfere with the absorption of non-heme iron.
  
  
• Protein. Most vegetarians obtain enough protein from plant-based sources such as legumes, nuts and seeds. However, these foods are lower in protein content than animal-based products such as meat, poultry, fish and eggs. As a result, vegetarians often have diets that are slightly lower in overall protein content than non-vegetarian diets. Unlike animal-based “complete” proteins, protein from plant sources usually lacks one or more essential amino acids. These are the building blocks of protein that only come from dietary sources.  To obtain all of the essential amino acids, vegetarians must eat a diversified diet of legumes, nuts, seeds, grains, vegetables and fruits.
  
  
• Vitamin B12. Also known as cobalamin, this vitamin helps the body make red blood cells and use fats and amino acids. Vegetarians who consume eggs and dairy products typically obtain adequate levels of dietary vitamin B12. However, vegans need to look elsewhere for their intake of this vitamin. Typically, this involves either supplements or fortified foods such as breakfast cereals, soy milk or rice milk products, or vegetarian burgers. The vitamin B12 contained in sea-based plant foods such as spirulina, tempeh, sea vegetables and miso is inactive and cannot be absorbed. Deficiency of vitamin B12 typically causes no short-term health problems. However, over time it can result in megaloblastic anemia and severe, irreversible nerve damage.
  
  
• Vitamin D. This vitamin helps the body absorb calcium and phosphorus, which is important for strong bones and teeth. The body can make its own vitamin D if the skin is exposed to sunlight for about five to 15 minutes a day (or 20 to 40 minutes three times weekly). People who do not receive this type of sunlight can still get enough vitamin D through drinking milk, which typically is fortified with vitamin D. Because vegans do not consume milk, they need to be especially careful to get adequate levels of sunlight (particularly in northern climates) or to consume foods fortified with vitamin D, including breakfast cereals, some soy beverages and some calcium-fortified juices.
  
  
• Zinc. This mineral is crucial for growth, repairing body cells and production of energy. It is found chiefly in meat, poultry and seafood. Vegetarians can obtain zinc through milk, cheese, yogurt or eggs. Vegans may face an additional challenge in obtaining enough zinc. However, many plant-based foods provide zinc, including whole grains, wheat germ, legumes, tofu, seeds and nuts. Zinc supplements usually should not be taken unless recommended by a physician.

In general, vegetarians can use plant-based foods to substitute for animals products, including the following: