Around 3% of Belgian children follow vegetarianism that excludes eggs, meat, dairy products and all other ingredients that are animal-derived, and this is according to the statement from Belgium's Royal Academy of Medicine. The eating plan is restrictive and it creates unavoidable nutritional shortcomings and it could lead to deficiencies and stunted development if it is not properly monitored, the academy said.

The medical opinion was requested by a representative of a national human rights organization, who wanted guidance for pediatricians and other health care workers. The Royal Academy of Medicine works as an advisory agency for Belgium's government institutions.

Dr. Georges Casimir, a pediatrician at Queen Fabiola Children's Hospital and head of the commission appointed by the academy to study the issue of veganism, does not recommend the vegan diet for children and pregnant women because of the possibility of irreversible harms. A potential health issue caused by a vegan diet is the lack of sufficient proteins and essential fatty acids for the developing brain.

Vitamins, including Vitamin D and B12 which are essential ingredients, calcium or even trace nutrients and elements that are essential for proper development are absent from the vegan diet, according to a statement from Casimir.

Isabelle Thiebaut, a co-author of the opinion and president of a European organization for dieticians, said that it is important to explain to parents about "weight-loss and psychomotor delays, undernutrition, anemia" and other possible nutritional shortfalls caused by a vegan diet for children.

If parents do not follow the new recommendation, the children who will continue to follow the vegan diet should receive medical follow-ups, regular blood tests, and supplements, according to the academy.

However, not everyone agrees with the academy's statement. The British Dietetic Association said that "well-planned plant-based, vegan-friendly diets can be devised to support healthy living at every age and life-stage."

Great Britain has about 600,000 vegans, roughly 1.2% of the population in 2018, according to the nonprofit Vegan Society.

The same opinion is maintained in the United States.

"Appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases," according to the Academy of Nutrition and Dietetics, a US organization for nutrition professionals.

"These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes."

The position paper of the organization also states that vegans are at reduced risk of certain health conditions such as Type 2 diabetes, certain types of cancer, heart disease, and obesity.