Infants, children, adolescents, and pregnant and lactating women have been described as groups with special needs. Regardless of diet chosen, these groups are at higher risk for nutritional deficiencies than adult males. Vegan diets can be safely used by these groups if foods, and in some instances supplements, are selected which provide a healthful and nutritionally adequate diet. Guidelines have been developed for those choosing to follow vegan diets. In many instances vegan diets offer health benefits. Studies of vegans are (...) limited by factors such as heterogeneity of diets, the size and extent of this type of study, and difficulty in subject identification. There is a scarcity of studies of newer vegetarians who are often more mainstream than the vegetarians of the 1960s and 1970s. In some instances this has led to assumptions about today's vegans which are based on out-dated information. Thorough scientific studies of today's vegetarians, especially of those in groups with special needs, are needed. (shrink)