Vegetarians and people who don't consume much meat should carefully monitor their diets and ensure adequate intake of certain nutrients, vitamins and minerals. Animal products are the richest sources of some vitamins. People who don't consume meat can get adequate vitamins if they have a balanced, varied diet and take supplements, if needed.
According to the American Heart Association, vegetarians should monitor their diets carefully to ensure adequate intake of protein, iron, vitamin B-12, vitamin D, calcium and zinc. Vitamin B-12 is found naturally in only animal sources. It's also present in fortified cereals, soy beverages and some brewer's yeast. Vitamin D is found in natural sunlight. It's also found in the flesh of fish and fish liver oils. Small amounts are present in beef liver, cheese and egg yolks.
Vitamin D maintains normal blood levels of calcium and phosphate, according to the National Institutes of Health. It promotes calcium absorption and bone health. It's also important to immune function and reduces inflammation. Vitamin B-12 is needed for for proper red blood cell formation, neurological function and DNA synthesis. It also helps to convert food to energy.
Vitamin B-12 can prevent a type of megaloblastic anemia and pernicious anemia, according to the National Institutes of Health. Vitamin D is used to treat familial hypophosphatemia, a rare genetic disorder characterized by impaired phosphate transport in the blood and inhibited vitamin D metabolism in the kidneys. It also treats Fanconi syndrome, hyperparathyroidism, osteomalacia, psoriasis and rickets.
Although not vitamins, certain other nutrients and minerals are especially important to vegetarians. Vegetable sources of protein are found in beans, nuts and whole grains. In addition to meat, iron can be found in lentils and beans. Vegans may need calcium supplements because the richest calcium sources are milk, yogurt and cheese. Calcium is also found in Chinese cabbage, kale and broccoli. Vegetarians can get zinc from beans, nuts, whole grains, fortified breakfast cereals and dairy products.
Adolescents aged 14 and over and adults should get 2.4 micrograms of vitamin B-12 per day. Vegetarians should consider vitamin B-12 fortified foods, which are foods that have B-12 added to them, oral vitamin B-12 supplements or vitamin B-12 injections. The Adequate Intake, or AI, for vitamin D is 5 micrograms for adults ages 19 to 50, 10 micrograms for ages 51 to 70, and 15 micrograms for adults over age 70. Strict vegetarians may want to consider supplementation.