Some animal-based foods high in protein contain nutrients that plant-based protein foods lack. If you consume a vegan diet and avoid animal protein foods, consider supplementing with nutrients your diet may be lacking. The human body utilizes animal proteins differently from plant-based proteins. According to the American Dietetic Association, however, vegetarian and vegan diets can be nutritionally adequate when correctly planned, appropriate for all individuals and may provide health benefits.
Nine amino acids cannot be manufactured by the human body; therefore, they are considered essential amino acids. Complete proteins contain all nine essential amino acids. With the exception of soy protein, animal proteins are complete proteins while plant-based protein foods are incomplete proteins. Consuming different combinations of plant-based proteins, however, can still provide the body with the essential amino acids it requires. According to the U.S. Department of Agriculture, the recommended dietary allowance for protein in adults is 56 grams for men, 46 grams for women and 71 grams per day for pregnant and lactating women.
Important nutrients for people limiting animal protein include omega-3 fatty acids, iron, calcium, zinc and vitamin B12, according to the American Dietetic Association. These nutrients are lacking or limited in plant-based protein foods. Dietary cholesterol, although unessential since the human body can make it, is a nutrient absent from plant-based protein foods.
Although many plant-based foods such as cereals are fortified with vitamin B12, the best sources of vitamin B12 come from animal protein foods like meat, fish, chicken, clams, milk, eggs and other dairy products, according to the National Institutes of Health Office for Dietary Supplements. Although zinc is found in small amounts in some plant-based protein foods, such as beans, whole grains and nuts, the main source for zinc is animal-based protein foods, such as poultry, red meat, oysters, seafood and milk, according to the Office for Dietary Supplements. The form of iron that is best absorbed by the body is found in chicken liver, red meat, poultry, fish and seafood. Fish is an excellent source of omega-3 fatty acids.
Consuming a vegan diet can quickly cause malnutrition including iron-deficiency anemia, if not planned properly. Since plant-based protein sources of iron are not absorbed as well, consume vitamin C to help increase iron absorption in your body.
Depending on the type of vegetarian diet you consume, nutrient supplementation is typically recommended by a health care professional. If you’re following a vegan diet, consume complete proteins from soy or combinations of plant-based proteins, such as peanut butter on wheat bread or rice and beans.