The Impact of Protein Source on Nutrient Intake in Canadian Children

Establishing healthy and balanced dietary habits in childhood is central to building a strong foundation for nutritional wellbeing that carries through to adulthood. 

Shifting nutrition policies and guidelines that emphasize plant-source foods have led researchers to explore their potential nutritional impacts. A recent analysis of the 2015 Canadian Community Health Survey (CCHS) linked higher plant-based protein intake led to lower intakes of protein, vitamin D, vitamin B12, calcium, and zinc among adults, with greater effects observed in older adults.¹  

In light of these findings, a 2025 study assessed the relationship between different dietary protein sources and nutrient intake among Canadian children aged 9-18 years.² 

The authors analyzed 24-hr dietary recall data from the 2015-CCHS for 2,324 children and adolescents aged 9-18. Participants were grouped into four categories based on their plant-based protein intake: Group 1 (0-24.9% of protein from plant sources), Group 2 (25-49.9%), Group 3 (50-74.9%), and Group 4 (75-100%). Thus, participants in Group 1 obtained most of their protein from animal sources, while those in Group 4 relied predominantly on plant-based proteins. Nutrient intakes were compared against the age-specific Recommended Dietary Allowances (RDAs) or Adequate Intakes (AI) for different nutrients, and protein quality was assessed using the Protein Digestibility-Corrected Amino Acid Scores (PDCAAS). 

The number of participants in each group was as follows: 691 participants in Group 1 (29.7%), 1,246 in Group 2 (53.6%), 324 in Group 3 (13.9%), and 63 in Group 4 (2.7%). Group 2 (25-49.9% protein from plant sources) was selected as the reference group, as they represented the largest group. The authors note that the small sample size and variability in Group 4 complicate drawing firm conclusions for this group. 

Overall, among Canadian children aged 9-18, 64% of daily protein came from animal sources and 36% from plant sources, on average. Across all gender and age categories, increased plant-based protein led to a subsequent decreased intake of total protein, total saturated fatty acids, vitamin D, vitamin B12, calcium, phosphorus, and zinc.  

Additionally, the authors present the following gender-specific findings to highlight nutrient intake differences by plant-based protein consumption. 

Female participants:  

• Across all age groups, the group with the lowest plant-based protein contributions (Group 1: 0-24.9%) had higher intakes of vitamin B12, vitamin B6, potassium, phosphorus, and zinc compared to the reference Group 2.  
• For females aged 14–18, nutrient intakes in Group 4 were lower in total fat, total saturated fatty acids, vitamin D, vitamin B12, riboflavin, niacin, and phosphorus compared to Group 2. 
• In Group 4 (highest proportion of plant-based proteins), average vitamin B12 intakes among female participants fell 41% below the RDA for those aged 9–13, and 50% below for those aged 14–18. 

Male Participants: 

• Across all age groups, those with the lowest plant-based protein contributions (Group 1) had higher intakes of total protein, vitamin B12, vitamin B6, niacin, riboflavin, potassium, phosphorus, and zinc compared to Group 2. 
• Intakes in Group 4 for males between ages 14-18 were lower in total protein, total fat, total saturated fatty acids, vitamin D, vitamin B12, vitamin B6, calcium, niacin, phosphorus, and zinc when compared to Group 2. 
• The average vitamin B12 intakes among male participants in Group 4 fell 24% below the RDA for those aged 9-13, and 40% below for those aged 14-18.  

The authors note that these results are in line with previous conclusions that Canadian children are at risk of inadequate calcium, potassium, vitamin D, and fibre intakes, while consuming excess sodium. More specifically, in Groups 1-3, the average intakes of folate and vitamin D were below 66% of the RDA, while that of calcium was below 88% of the RDA, underscoring the importance of balancing animal and plant proteins appropriately to avoid exacerbation. 

While dairy foods consistently ranked among the top three protein sources in children’s diets across all four groups, calcium intake nonetheless remained below recommended levels in all groups. The authors highlight the need to reinforce the role of dairy in children’s diets, as emphasized in previous dietary guidelines. Recent declines in milk consumption may contribute to these nutrient gaps. However, while often perceived as replacements, most plant-based beverages (except for soy) offer lower protein quality and quantity compared to dairy. In addition to its nutrient density, dairy consumption has also been associated with favourable health outcomes. For example, the authors highlight that children who consume whole milk have a 16% lower risk of becoming overweight and an 18% lower risk of obesity compared to those who consume low-fat milk.³  

Total protein intakes decreased with increasing plant-protein contributions, which was further exacerbated by adjustments for protein quality. The reduction in protein intake between Groups 1 and 4 was twofold, and the latter (Group 4) did not meet their protein requirements after adjustment for protein quality. Among children in Group 3, dairy products were the primary source of protein, while in Group 4, the main contributors were breads, crackers, and rolls.  

The authors note that an animal-to-plant-based protein ratio of 3:1 was associated with optimal macronutrient balance while meeting most essential nutrient requirements.  

Overall, the study highlights that the recommended shift toward plant proteins, such as certain recommendations in the 2019 Canada’s Food Guide, must be approached with caution, as certain micronutrients are less bioavailable from plant sources—posing nutrient inadequacy risks for children. This underscores the importance of food fortification and supplementation strategies to prevent exacerbation of existing nutrient inadequacy concerns among children. 

Finally, the authors emphasize that due to the potential risk of nutrient inadequacies associated with primarily plant-based protein intake among Canadian children, careful consideration must be given to dietary diversity, nutrient density, and potential nutrient trade-offs.