Many people choose to follow a vegetarian diet for health reasons, and many choose one for moral reasons. Vegetarian diets vary in the details, with some allowing milk or eggs, or milk and eggs, or no animal products at all. The one thing that is the same in all vegetarian diets is the exclusion of meat. When meat is taken out of the diet completely, you must find a way to replace specific nutrients that only animal products can provide. Plant sources are sometimes available, but often a vegetarian will have to take supplements to get the proper amounts. Consult with your doctor before supplementing any dietary nutrient.
Protein is perhaps the most well-known reason for eating meat. Plant sources of protein are incomplete by themselves, meaning they don't contain all of the essential amino acids. Nonmeat eaters must either combine a plant protein and starch, such as red beans and rice, or supplement to get the full profile. Protein powders such as whey, soy and hemp are good choices to add quality, complete protein if you aren't getting enough.
Red meat liver and egg yolks are good sources of iron from the animal kingdom. Iron is responsible for carrying oxygen through your bloodstream to all the cells in your body. Iron deficiency is known as anemia, and it causes fatigue due to low oxygen levels in the blood. Have your doctor test your iron levels before supplementing with iron.
Vitamin B12 is part of the B-complex of vitamins and is only available naturally in animal products. You can get vitamin B12 if you eat eggs and drink milk, but for vegans it is usually necessary to supplement. Vitamin B12 assists with your metabolism and helps the body produce red blood cells.
Zinc is an essential trace mineral that is found in every cell of your body, according to the University of Maryland Medical Center. Zinc is found in red meat, fish, chicken and oysters, and helps with cell division, the formation of proteins in the body, immune and reproductive health, taste, vision, smell, blood clotting, insulin and thyroid function. Zinc is also found in plant sources such as legumes, cooked greens, mushrooms and pumpkins. Plant-based zinc is less easily absorbed by the body than from meat, so vegetarians may want to supplement to keep levels up.
Omega-3 fatty acids are essential to cardiovascular health, eye and brain function. Nonmeat eaters can get omega-3s from flaxseeds, walnuts and avocado, but plant-based versions of omega-3s convert to what humans need inefficiently, according to MayoClinic.com. Omega-3s are found primarily in oily fish such as mackerel, herring, sardines and salmon, so vegetarians will either have to take a fish oil supplement or be content with plant-based sources, including flaxseed oil supplements, of omega-3s.