"..appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases.
Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence and for athletes.."

Position of the American Dietetic Association
www.ncbi.nlm.nih.gov/pubmed/19562864

Position of the Academy of Nutrition and Dietetics
www.ncbi.nlm.nih.gov/pubmed/27886704