Experts say a strict diet can deprive a child of vital nutrients and vitamins, which can lead to malnutrition and other serious health problems.

In July 2016, The Washington Post published a story about an Italian couple who lost custody of their 14-month-old son.

The boy had been admitted to the hospital weighing about as much as an average 3-month-old baby.

He required emergency surgery for a congenital heart condition aggravated by low calcium levels.

The reason for the low calcium levels and general malnourishment?

His parents had been keeping their young son on a strict vegan diet since birth without providing any supplements to make up for the nutrients he was missing out on.

According to the Post, this case was not unique.

In fact, it was the third case of a child in Italy being hospitalized as a result of a vegan diet.

And there have been similar cases around the world dating back to 2004. In one case, a couple in the United States was sentenced to life in prison after their baby died as a result of malnourishment.

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At the 50th annual meeting of the European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) earlier this month, experts decided to speak up about the dangers of a vegan diet for children without proper supplementation.

“It is difficult to ensure a healthy and balanced vegan diet in young infants, and parents should understand the serious consequences of failing to follow advice regarding supplementation of the diet,” Dr. Mary Fewtrell, chair of ESPGHAN’s nutrition committee, said in a press statement. “The risks of getting it wrong can include irreversible cognitive damage and, in the extreme, death.”

Dr. Myriam Van Winckel, a professor in the department of pediatrics and medical genetics at Ghent University in Belgium, had something similar to share.

“The more restricted the diet of the child, the greater the risk of deficiency, and this is by far highest in vegan children,” Van Winckel said in a press statement. “But the risk does not stop there. Vegan mothers who breastfeed also need to be aware that their children can develop vitamin B-12 deficiency between 2 and 12 months because of the lack of reserves in their body at birth, even if the mother is not showing any signs of deficiency herself.”

Officials at ESPGHAN are not the only ones to sound an alarm.

A 2010 article by the Canadian Paediatric Society showed data compiled from several studies of strict vegan preschoolers and school-age children.

Concerns were raised regarding protein, fiber, essential amino acids, iron, zinc, calcium, fat, fatty acids, vitamins B-12, D, A, and riboflavin.

The researchers added that energy levels may be impacted as well, requiring “calorie dense foods to provide for adequate growth.”

The article concluded that while a vegan diet can be safe for children, those children should be closely monitored for appropriate nutrition, growth, and energy levels.

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Members of the American Academy of Pediatrics (AAP) also expressed their concerns.

“Childhood is a critical time for growth and brain development,” Dr. Sheela Magge, an endocrinologist at Children’s National Health System, told Healthline. “There are critical vitamins and minerals which can be deficient in a vegan diet, particularly vitamin B-12, vitamin D, iron, calcium, zinc, and riboflavin. Vegan diets can also increase the risk of vitamin A deficiency. B-12 comes from milk and eggs and is a specific concern for people on a vegan diet. A lack of sufficient vitamin B-12 can lead to neurological symptoms. Children on vegan diets may also have slightly higher protein requirements than non-vegan children.”

She added that the first few months and years of life are particularly important.

“Infancy is a special consideration,” Magge said. “The ideal first nutrition for babies is breast milk, but if a mother does not or cannot feed the baby breast milk, the only other option is a soy-based formula. Also, during infancy and weaning the amount of food needed to meet energy needs on a vegan diet may be increased and can exceed gastric capacity. Therefore, frequent feeds are recommended.”

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So what are the options for parents who are committed to a vegan lifestyle?

According to Magge, it can be done — but only with careful monitoring.

“A child can be on a vegan diet safely, but it should be done in consultation with the child’s pediatrician or primary caregiver,” she said. “A nutritionist may also be involved. Childhood is a critical time for growth and development, and it is very important that adequate amounts of critical vitamins and minerals are taken in the child’s diet at specific times in development.”

Kristin Kirkpatrick, MS, RD, LD, a licensed, registered dietitian, who is a wellness manager at the Cleveland Clinic, agreed, but she added parents need to carefully assess the willingness of the child to go along with such a strict dietary plan.

“This plan will most likely not work in a very picky eater and could lead to nutrient deficiencies,” she said.

When considering a vegan diet for a child, experts say consulting with a pediatrician is the best way to ensure proper nutrition.