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A study published in the Critical Reviews in Food Science & Nutrition looks at the risks and benefits of vegan diets in children.
Prof Martin Warren, Chief Scientific Officer, Quadram Institute Bioscience, said:
“This is an interesting and highly timely study. While much current debate focuses on the health effects of ultra-processed foods high in fat, sugar, and salt, this analysis shifts attention to the very different question of how lacto-ovo-vegetarian and vegan diets affect children’s health. The authors take a notably comprehensive approach, comparing multiple dietary patterns across a wide array of nutrient intakes, biomarkers, and growth outcomes. The large pooled sample and clear distinction between lacto-ovo-vegetarian and vegan cohorts add further weight to the findings.
“As with all observational research, the study cannot establish causality, and the abstract suggests that important confounding factors, such as socioeconomic status, parental education, or typical supplementation practices, may not have been consistently accounted for. Nevertheless, the results are striking. They underscore that while plant-based diets in childhood may offer some health advantages, the risks of micronutrient deficiencies remain real and should not be underestimated. Ensuring appropriate supplementation, or developing nutritionally enriched foods tailored for plant-based children, will be essential if these diets are to support optimal growth and development. Overall, the study provides a valuable reminder: dietary choices in childhood matter profoundly, and nutritional adequacy must always be at the forefront of the discussion.”
Dr Ian Johnson, Nutrition researcher and Emeritus Fellow, Quadram Institute, said:
“This very thorough analysis of research on the effects of vegetarian and vegan diets in infants and children provides a welcome addition to knowledge. The physiological demands of growth and development mean that children are more vulnerable to nutritional deficiencies than adults. This study provides reassurance that children can thrive on vegetarian and vegan diets, but it also sounds a cautionary note. Parents and the health professionals who support them should be aware that supplements and/or fortified foods may be needed to ensure that wholly plant-bases diets, provide the micronutrients needed to meet all the needs of growing children.”
Comments from our colleagues at SMC Spain:
Eduard Baladia, researcher at the Centre for Analysis of Scientific Evidence of the Spanish Academy of Nutrition and Dietetics (CAEC-AEND), says:
“The article is of acceptable methodological quality and appears to follow the standards expected of a systematic review with meta-analysis: it has been pre-registered, details the search strategy, explains the selection criteria and describes the process of critical appraisal, data extraction and statistical analysis. This does not mean that there are no areas for improvement (all reviews have them), but at least it reports the fundamental elements that allow its transparency and rigour to be assessed. My assessment is preliminary because an in-depth analysis would require more time.
This meta-analysis fits reasonably well with the existing evidence: it confirms that vegetarian and vegan children tend to consume less energy and some micronutrients than omnivores, but that does not automatically imply that their intake is insufficient. In many cases, it simply reflects that omnivores tend to consume above the recommendations, while vegetarian families tend to better adjust their diet to the recommendations.
An important nuance is that the meta-analysis’s overall table mixes studies from countries with very different socioeconomic levels. In low-income contexts (especially in India, which contributes many studies), the differences observed may not be due to the vegetarian pattern itself, but to inequalities in access to food. Therefore, some of the differences in intake and biochemical markers could reflect poverty rather than an inherent risk in the diet. But again, the authors say, and I quote: ‘However, average energy and protein intake remained, in general, within the recommended ranges.’ ‘In both ovo-lacto vegetarians and vegans, most mean values, including ferritin and 25(OH)D [active form of vitamin D], remained, in general, within paediatric reference ranges.’
In high-income countries, where access to food and supplements is adequate, the results show differences in intake but few signs of overt deficiencies, except for the possible increased likelihood of anaemia in lacto-ovo-vegetarians.
The main limitation is that the meta-analysis compares average intakes between groups but does not report how many children actually fall short of the recommended values. This makes it difficult to know whether lower intake is clinically relevant or simply reflects more moderate but adequate consumption.
Another limitation is the mix of socioeconomic contexts (without access to the analysis that the authors have done but do not report in full): data from low-income countries may amplify differences and are not fully comparable with those from Spain or Europe. Biochemical markers are also not adequately broken down by income level, which is key to interpreting ferritin, vitamin A, D or E, given that these deficiencies are much more common in vulnerable populations regardless of dietary patterns. In these settings (low-income countries), being vegetarian may be associated with lower purchasing power or less access to food, which could distort the conclusions.
There are four statements made by the authors that should be given serious consideration:
This statement summarises the data quite well. The meta-analysis finds no consistent evidence that vegetarian or vegan children in high-income countries grow less well or have serious clinical deficits. However, lower intakes and some reduced biomarkers are observed, which in principle do not imply disease but do justify regular monitoring and appropriate dietary planning. In other words, these diets are viable and safe, but they cannot be improvised.
This is consistent with the evidence: vegetarian and vegan children consume sufficient protein, but not always with an optimal amino acid profile if their diet is based on very few plant foods. However, in a minimally varied diet, such as that which any family in our context can follow, this aspect does not represent a real problem. The availability of protein-rich plant foods, the regular presence of complementary food combinations, and widespread access to nutritional information make the risk of suboptimal protein intake virtually non-existent. This is not an inherent limitation of vegetarian diets, but a reminder that, like any dietary pattern, they require variety and basic planning, which is perfectly achievable in high-income societies such as ours.
This statement carries particular weight because vitamin B12 is not available in plant foods. However, rather than providing new information, this meta-analysis reinforces already well-established evidence: properly supplemented vegan children achieve adequate levels of B12 and may even have a status equal to or higher than that of omnivores. Therefore, the key point is not to discover something new, but to confirm once again that the risk does not lie in the plant-based diet itself, but in the absence of supplementation, an aspect that in our healthcare context is well understood and easy to manage.
This is one of the most interesting observations of the meta-analysis, but also one that calls for caution. The authors interpret that although vegetarian and vegan children tend to consume more total iron—from non-haem iron in plant foods, which is less well absorbed than haem iron from animal sources—this lower absorption could explain the lower ferritin levels and higher likelihood of anaemia observed. The explanation makes physiological sense, but it is unclear whether the intake and ferritin data come from the same subjects. When comparing aggregate results from different studies, there is a risk of committing an ecological fallacy, i.e., assuming individual relationships based on patterns that are actually only observed at the group level (and in this case, possibly in different studies).
The meta-analysis combines studies where some report intakes and others report biomarkers, and these data are not always directly related. Added to this is another important limitation: most studies are cross-sectional, so we cannot rule out reverse causality. That is, it may be that children with low ferritin have been advised to increase their iron intake, which would produce exactly the pattern we see: higher intakes along with lower ferritin levels, but without intake being the cause of the reduced biomarker. Therefore, although the authors’ interpretation is plausible, we cannot say with certainty that the higher proportion of non-haem iron explains the lower ferritin levels. Well-designed longitudinal studies or trials are needed to simultaneously analyse intake, absorption and biomarkers in the same individuals.
José M. Ordovás, Director of Nutrition and Genomics at Tufts University in Boston (USA), member of IMDEA-Alimentación (Madrid) and CIBEROBN (Carlos III Health Institute), says:
“Overall, this meta-analysis is a solid and well-executed piece of work. It includes nearly 50,000 children from 59 studies in multiple countries, giving it a broad and fairly robust view of vegetarian and vegan diets in childhood. Even so, most of the evidence is observational and cross-sectional, so the associations should be interpreted with caution; this does not allow causality to be established.
The results confirm what we already knew from previous studies: these diets can be healthy in childhood, but they require careful planning and adequate supplementation to avoid micronutrient deficiencies. The overall pattern is clear: more fibre and vitamins from plant foods, less saturated fat and cholesterol, and a more favourable cardiometabolic profile. This is consistent with the literature on healthy dietary patterns.
The article adds important nuances: even when the average intake of many nutrients is within acceptable ranges, body stores of iron, vitamin D and, in vegans, vitamin B12 may be lower, confirming the need for clinical monitoring and systematic supplementation, especially for B12 and vitamin D.
There are several limitations or critical points. The studies included are very heterogeneous, many with small samples, different methods for measuring diet and, often, without clear information on supplementation. Therefore, the results are indicative, not definitive.
[Regarding possible lower energy intake] Vegetarian and vegan children tend to consume less energy and slightly less fat and protein. This is reflected in a slightly thinner phenotype, with slight differences in height or weight, but in most cases within the normal paediatric range. The available evidence does not show a relevant clinical impact on growth when the diet is well planned and supplemented. However, in contexts with less access to fortified foods or less professional monitoring, this risk could increase.
In summary: a vegetarian or vegan diet in childhood can be healthy, but it is not “automatically” healthy. It requires knowledge, supervision, a varied diet and mandatory supplementation of vitamin B12 and, in most cases, vitamin D; and, for vegans, special attention to calcium, zinc and iron. With this support, children can grow properly and also benefit from healthier eating habits for life.”
Javier Sánchez Perona, senior scientist at the Instituto de la Grasa-CSIC, says:
“The study is a systematic review and meta-analysis comparing ovo-lacto-vegetarian and vegan diets with omnivorous diets in children and adolescents (<18 years) in different countries around the world, thus providing a valuable synthesis of current evidence in paediatric populations. It is the most comprehensive synthesis to date on this type of diet in childhood and adolescence, including 59 studies and more than 48,000 participants. The results were stratified by country income level (low/medium versus high) and by age (preschool <6 years and school >6 years).
The study confirms that well-planned plant-based diets can support healthy growth in this population and offer advantages such as lower total and LDL cholesterol concentrations. In addition, these children tend to be slimmer and at lower risk of becoming overweight. However, if diets are not well supervised, they run other risks, such as vitamin B12 deficiency (vegans), anaemia and shorter stature, the latter possibly associated with iron, calcium and vitamin D intake. Interestingly, vegan children consumed more iron than omnivores, but it was not enough to maintain ferritin levels because it was non-haem iron.
The authors state that randomised controlled trials were not included because the intention was to observe associations between regular consumption of these diets and nutrient intake and nutritional status markers, but it would be appropriate to do so in the future in order to make causal inferences.
On the other hand, high heterogeneity in the results was found due to age. Although stratified by age (<6 years and >6 years), there is a significant difference in physiological maturity between children around 6 years of age and adolescents up to 18 years of age, who were in the same group.
Another point of criticism is that only four studies excluded participants who took supplements, and the use of these was reported inconsistently in the studies. This complicates the interpretation of the results and could lead to the situation where unsupplemented ovo-lacto-vegetarian and vegan diets lead to higher risks of intake deficiencies than observed. Furthermore, no data on bone markers were available for vegan participants.
Therefore, although this is a very valuable study, it would need to be supplemented by prospective studies and clinical trials to assess the long-term effects of these diets on paediatric development.”
‘Lacto-ovo-vegetarian and vegan diets in children and adolescents: a systematic review and meta-analysis of nutritional and health outcomes’ was published in Critical Reviews in Food Science & Nutrition at 05:01 UK time on Friday 12 December 2025.
DOI: 10.1080/10408398.2025.2572983
Declared interests
Eduard Baladia: “None financial. Yes academic: on several occasions I have defended from an academic point of view the vegetarian and vegan pattern throughout the life cycle, which could include in my inertia to thoroughly review what offers data against it. Personal (although more than 10 years ago): 10 years ago, I went through a period of following a vegetarian diet, and although I am not vegetarian now, my experience may influence my perception of risk (in this case, a lower perception).”
José M. Ordovás: He declares that he has no conflicts of interest in relation to this topic
Dr Ian Johnson: “No conflicting interests to declare.”
Javier Sánchez Perona: He declares no conflicts of interest.
For all other experts, no reply to our request for DOIs was received.