Kajiura et al. (2026) - vegan diets and iron deficiency in children?


Another systematic review on health and nutrient biomarker status on "plant-based", including vegan children, has just been published.

I was surprised by one thing in the abstract.

The publication is "Impact of Plant-Based Diets on Children's Growth, Nutritional Biomarkers, and Health Outcomes and Risks: A Systematic Review" by Kajiura et al. (2026).

In the abstract, it says:
"vegan diets [...] were often accompanied by iron [..] deficiencies".

As a naive person, this would make me think that there are several studies that showed iron deficiencies in vegan children, more often than in omnivorous children.

I looked at the article.
It says that ...
  • (1) in a study from Poland - Desmond et al. (2021; n = 52 vegan children) - vegans had a higher prevalence of iron deficiency and that ...
  • (2) in a study from Canada - Elliott et al. (2022; n = 25 vegan children), "No significant difference in serum ferritin" was found between vegetarian (including vegan) and omnivorous children. (The study by Elliott et al. did not report results for vegan children separately, it seems), and that ...
  • (3) a study from Finland - Hovinen et al. (2021; n = 6 vegan children) "found no significant differences in serum ferritin or transferrin receptor levels between vegan and omnivorous preschoolers. Interestingly, children on vegan diets had higher serum ferritin levels than vegetarians but similar levels to omnivores in this study. [...] All iron-related biomarkers and intakes were within reference ranges [...]".
So, in total, there seem to be three studies, but only two studies reported a difference between vegan and omnivorous children - one: more iron deficiency (bigger study); one: no difference (very small study).

Still, I don't think this justifies the statement: "vegan diets [...] were often accompanied by iron [..] deficiencies".


Kajimura et al. also write in their article: "[...] ferritin was lower in several vegetarian/vegan cohorts; the strongest signal was reported in vegans in Desmond et al.".

Not necessarily incorrect, but regarding vegan children, a higher prevalence of iron deficiency in vegan children was only observed in that study (Desmond et al.).

Their article is otherwise wonderful (I think - I haven't checked every detail).






Reference

Akiko Kajiura 1, Zhangyun Ju 1, Jennifer T Smilowitz 1, Carolyn M Slupsky: Impact of Plant-Based Diets on Children's Growth, Nutritional Biomarkers, and Health Outcomes and Risks: A Systematic Review. Nutrition Reviews. 2026 May 25:nuag072. doi: 10.1093/nutrit/nuag072. Online ahead of print.