Are the IQs of Vegetarian Children Higher?

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Are the higher IQs found in vegetarian children the result of confounding factors or reverse causation?

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Dennis may be referring, watch the above video.

Many vegetarian parents believe their children are brighter than omnivorous kids, but you don’t really know until you put it to the test. And indeed, the IQ of vegetarian children tested about 16 points higher than average, and their mental age exceeded their chronological age by about a year. The researchers knew the veg kids were bright, but why were they so much more superior? There are obviously confounding factors, like maybe more highly educated parents are more likely to have vegetarian children, and they pass down both their brains and their diets.

Even if there is a cause-and-effect relationship between vegetarianism and IQ, were the children smarter because they were vegetarians, or did they become vegetarian because they were so smart? Researchers in the UK followed 8,000 kids for decades. They measured their IQ at age 10, then came back 20 years later and asked which of them had become vegetarian during that time. And indeed, the smarter kids had an increased likelihood of being a vegetarian as an adult. The researchers even quoted Benjamin Franklin saying that vegetarian diets result in “greater clearness of head and quicker comprehension.”

According to the largest and oldest association of nutrition professionals in the world, strictly plant-based diets are appropriate for all stages of the life cycle, including childhood, and may indeed provide health benefits. What about plant-based diets and growth in children? Some studies show that children raised on restrictive macrobiotic diets suffer from growth stunting, while others show that those raised plant-based may end up being up to an inch (2.5 cm) taller. In a systematic review and meta-analysis of children on vegan diets, heights were lower in vegans, but only because they included a study in which the vegan kids were significantly younger, mostly 10 to 14 years old, compared to mostly 15 to 19 years old. Once you remove the study with the age disparity, the height disparity also disappears.

What about width disparity? Population studies indicate that vegetarian diets are associated with a lower prevalence of obesity in both adults and children.

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Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Dennis may be referring, watch the above video.

Many vegetarian parents believe their children are brighter than omnivorous kids, but you don’t really know until you put it to the test. And indeed, the IQ of vegetarian children tested about 16 points higher than average, and their mental age exceeded their chronological age by about a year. The researchers knew the veg kids were bright, but why were they so much more superior? There are obviously confounding factors, like maybe more highly educated parents are more likely to have vegetarian children, and they pass down both their brains and their diets.

Even if there is a cause-and-effect relationship between vegetarianism and IQ, were the children smarter because they were vegetarians, or did they become vegetarian because they were so smart? Researchers in the UK followed 8,000 kids for decades. They measured their IQ at age 10, then came back 20 years later and asked which of them had become vegetarian during that time. And indeed, the smarter kids had an increased likelihood of being a vegetarian as an adult. The researchers even quoted Benjamin Franklin saying that vegetarian diets result in “greater clearness of head and quicker comprehension.”

According to the largest and oldest association of nutrition professionals in the world, strictly plant-based diets are appropriate for all stages of the life cycle, including childhood, and may indeed provide health benefits. What about plant-based diets and growth in children? Some studies show that children raised on restrictive macrobiotic diets suffer from growth stunting, while others show that those raised plant-based may end up being up to an inch (2.5 cm) taller. In a systematic review and meta-analysis of children on vegan diets, heights were lower in vegans, but only because they included a study in which the vegan kids were significantly younger, mostly 10 to 14 years old, compared to mostly 15 to 19 years old. Once you remove the study with the age disparity, the height disparity also disappears.

What about width disparity? Population studies indicate that vegetarian diets are associated with a lower prevalence of obesity in both adults and children.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

A note from Dr. Greger:

I am thrilled to introduce Dr. Kristine Dennis, our Senior Research Scientist. Dr. Dennis is an experienced nutrition and public health scientist who joined NutritionFacts to expand our research capacity — diving deep into the research, writing scripts, and now, narrating her own videos! You’ll continue to see videos from both of us interspersed in no particular order. I’m so happy Kristine is with NutritionFacts to help expand our capacity and perspectives.

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