The adoption of vegan and vegetarian diets in the teen years can trigger concerns over nutritional deficiencies and disordered eating. But new reports indicate few problems when these diets are followed correctly.
Interest in vegan and vegetarian diets has been growing over the past decade, and what may have started as a trend focused on animal protection and health benefits in adults is increasingly trickling down to the younger generation.
Although dietary preferences are an individual choice, some nutrition experts argue that when adults transfer these preferences to their kids, orthorexia by proxy becomes a concern.1 The alternative argument is that adolescents are at an age when they can make their own food choices and that exploring a vegetarian or vegan diet indicates they are interested in healthy choices.
The debate about whether such diets are appropriate for children and teenagers unlikely to be settled anytime soon, but pediatric health care providers should be aware of their nutritional benefits, the concerns they may raise, red flags to watch for, and when to refer patients to a nutritionist.
It can be difficult to determine the exact number of teens who choose vegetarian or vegan diets in the United States. According to one study, about 5% of North American adults were vegetarian in 2019 and about 3.7% were vegan.1 A German study from the same year revealed that parents who are vegetarian are increasingly sharing their diet choices with their children.2
That study also estimated that the number of vegetarians in Germany had increased from about 7% to 10% over the past decade, whereas only about 1% of the population was vegan. Young adults (aged 18 to 49) made up the largest proportion of vegetarians, the study notes, adding that roughly 2% of male teens and 6% of female teens considered themselves vegetarian.2
How these diets are defined can vary, but generally they exclude all types of meat, fish, and shellfish.1 Some vegetarian diets have additional restrictions, such as eliminating the use of eggs and dairy products. A vegan diet bans foods that include animal products.
Concerns over nutritional deficiencies in vegetarian and vegan diets usually get the most attention in debates about how appropriate they are for teens. And research does indicate that they could be deficient in the following1,3:
But it’s not just nutrients that can be missing from these diets. According to one report, sufficient knowledge about their risks and benefits is lacking among pediatricians and other health professionals, who perceive these diets as always being unbalanced.3
A position paper released by the Academy of Nutrition and Dietetics in 2016 concluded that properly planned and executed vegan and vegetarian diets could provide adequate nutrition and other health benefits at any stage of development.4 A 2022 study published in Pediatrics seemed largely to agree with this statement, revealing that there was no association between a vegetarian diet and growth or nutritional deficiencies in children aged 6 months to 8 years but there was a link between adherence to vegetarian diets and the number of underweight children.5
Moreover, a 2019 reference book endorsed by the British Dietetic Association failed to find sufficient evidence that vegetarian diets were lacking in nutrients for teens but stipulated that to succeed, adolescents on these diets had to carefully plan their nutritional intake and take nutritional supplements.6
More than one study has shown that perhaps the greatest risk posed by these diets is a lack of total calories. Research published in late 2021 concluded that vegetarian teen girls who had fewer than 3 meals a day were at a significantly higher risk of being underweight.7
Even proponents of vegan or vegetarian diets for teens stress the need for proper nutritional planning and supplementation. Reed Mangels, PhD, RD, an adviser to the nonprofit Vegetarian Resource Group and nutrition editor and columnist for Vegetarian Journal, says that these diets can meet the nutritional needs of a developing teen, provided there is adequate planning and support.
Mangels agrees that getting enough B12 is a major concern for vegans and vegetarians but says that protein intake isn’t usually a problem, unless the diet is used primarily to restrict calories. “The first thing is to…get a sense of what the teenage means when they say they are planning to go vegetarian,” she explains. “It can mean a lot of different things to different people.” Once you understand the individual’s motivation, the kind of diet they want to pursue, and how they plan to pursue it, you should gauge their understanding of both the diet and overall nutrition.
Following a plant-based diet is very different from going vegan or vegetarian, Mangels adds, and it’s important to determine whether the teen alone or the whole family is choosing the regimen. Identifying a support system for this lifestyle choice is important, too—especially if that support doesn’t exist.
Teens in vegan or vegetarian families and those who plan to change eating habits together may not need as much nutritional support and guidance from a health care team, she points out. On the other hand, a teen who is making the choice alone or with little to no family support is likely to need the help of someone like a registered dietician to figure out what and how much to eat.
There are numerous resources for those teens able to navigate the path to veganism or vegetarianism on their own, including VeganHealth.org, an evidence-based project to which Mangels contributes.
With the right planning and supplementation, she says, vegetarian and vegan diets can meet a teen’s nutritional needs and have numerous benefits, even if the person doesn’t stay vegan or vegetarian in the long term.
“There have been studies showing that teenagers who are vegetarian or vegan do eat more fruits and vegetables, and beans and grains,” Mangels says, and even those who don’t stick to their goals often end up incorporating more whole, healthy foods into their diets. In addition, pediatricians and parents can use even a slight interest in these diets as a way to promote healthy eating.
“It’s about planting that seed that this could be a really healthy way to eat if you are choosing fruits, vegetables, whole foods, and beans,” Mangels says, and working with the teen’s goals can result in healthier choices for the whole family.
Even families that don’t go all in on a vegan or vegetarian diet will likely consume more whole foods, she points out. And the practice also opens the door to a discussion about who should prepare the food. “Parents are responsible for making sure the teen is eating healthy foods. Starting a conversation about how it will fit into the family is important,” Mangels says, explaining that maybe this means having a conversation about how often the teen might cook a meal and clean up afterwards.
“It’s not about just saying, ‘hi, I’m vegan what are you going to make for dinner for me for the rest of my life?’” Mangels says. “This is potentially getting a teenager interested in healthy foods and cooking skills. These are life lessons, and their interest in what they are eating can be a springboard to other nutritional topics and information.”
Family support plays a significant role in the teen’s success with a vegan or vegetarian diet and how well their nutritional needs are met, Mangels says. Although highly motivated teens will do the necessary research, many without family support or participation will need guidance. This is especially true for those with limited cooking skills or whose parents won’t or can’t buy foods that provide the appropriate nutrients.
According to Mangels, pediatricians should also be aware of red flags that could signal a less-than-healthy motivation for changing diets. For instance, a teen who lists animal welfare or environmental concerns as a reason is more than likely genuinely motivated to pursue a vegan or vegetarian lifestyle. Teens with a history of suspicious eating patterns or who list weight loss as a motivator, however, should elicit more concern. Research also suggests that teens who claim to be vegetarian but still eat a lot of fish and chicken have higher rates of eating disorders, Mangels notes, and a reduction in carbohydrates or fat can also be a red flag.