Is your child vegetarian? Here is everything you need to know

Children who want to give up animal products need to be carefully monitored. New research shows that such a diet may lead to being underweight.

Vegetables are seen in vegetarian restaurant "Green Cuisine" in Minsk, Belarus February 1, 2018 (photo credit: VASILY FEDOSENKO / REUTERS)
Vegetables are seen in vegetarian restaurant "Green Cuisine" in Minsk, Belarus February 1, 2018
(photo credit: VASILY FEDOSENKO / REUTERS)

What to do if your kids want to be vegetarians? A new study suggests some factors to consider before making the switch, with findings showing that children who ate a vegetarian diet vs. those who ate a carnivorous diet showed similar spouts of growth, height and nutritional measures. However, vegetarian children were more likely to be underweight.

"Over the past 20 years, we’ve seen the growing popularity of plant-based diets and a changing food environment with more access to plant-based alternatives, yet we haven’t seen research on the nutritional outcomes of children following vegetarian diets in Canada," said Dr. Jonathan Maguire, the lead author of a recently published study in the journal Pediatrics and conducted at St. Michael's Hospital of the Unity Health network in Toronto.

The authors used data from nearly 9,000 children aged from six months to eight years old who participated in a follow-up group between 2008 and 2019. Their parents kept track of what the children ate and gave this information to the researchers. Whether the children were vegetarian, vegan or non-vegetarian was also noted. 

Study assistants measured participants' body mass index, weight, height, cholesterol levels, triglycerides, vitamin D levels, and serum ferritin levels several times throughout the study to note any changes.

Ferritin is a cellular protein that stores and allows the body to use iron when needed, so a ferritin test indirectly measures iron levels in the blood.

 Illustrative image of children eating vegetables. (credit: ZAKI AHMED/PIXABAY ) Illustrative image of children eating vegetables. (credit: ZAKI AHMED/PIXABAY )

When the study began, 248 children (including 25 vegans) were vegetarian. As the study progressed, that number grew to 586. The state of the children was tracked for approximately the next three years. The researchers found that there were no significant differences between non-vegetarian children in terms of standard BMI, height, serum ferritin levels and vitamin D. However, vegetarian children were almost twice as likely to be underweight than non-vegetarian kids.

Being underweight can be a sign of malnutrition and can indicate that a person's diet is insufficient to support proper growth, the study notes. Specific details about dietary intake or quality, and physical activity — like sports which can affect growth and nutrition — weren't available to the authors.

Studies with longer follow-up periods and information on the reasons for being vegetarian, such as socioeconomic status, will also be helpful in understanding the links between child development and vegetarianism, the authors said.

The study's findings emphasize the "need for careful nutritional planning for underweight children when considering vegetarian diets, and in general regardless of the diet chosen," said Maguire.

He added that a vegetarian diet can be a healthy choice for all kids — the key is to make sure that it is well designed. A certified nutritionist can help monitor growth and make sure they eat enough nutritious food to meet their nutritional needs and ensure that they properly develop cognitively and physically.