New research suggests early childhood diet is linked to small differences in IQ by age eight
Researchers at the University of Adelaide examined how feeding patterns in the first two years of life relate to cognitive outcomes at school age. The study followed more than 7,000 children and compared different dietary patterns at 6 months, 15 months and 24 months with IQ measured at eight years old. The findings indicate that children fed healthier diets during this crucial developmental window can show slightly higher IQ scores, while frequent early exposure to junk food is associated with slightly lower scores.
The research team classified diets into several patterns, including traditional home-prepared foods, contemporary meals prepared at home, commercially ready-prepared baby foods, breastfeeding, and discretionary or “junk” foods such as biscuits, chocolate, sweets, soft drinks and chips. The investigators looked for consistent associations between those early dietary patterns and later cognitive performance.
Key findings include a modest advantage for children who were breastfed at six months and who regularly consumed nutrient-rich foods—such as legumes, cheese, fruits and vegetables—at 15 and 24 months. These children scored up to two IQ points higher at age eight compared with children who did not follow that pattern. Conversely, children who regularly consumed discretionary foods in the first two years tended to score up to two IQ points lower by age eight.
The study also found mixed effects for commercially prepared baby foods: some negative associations with IQ when those products were given at six months, and some positive associations when used at 24 months. The authors note that the composition of ready-prepared foods varies widely, and timing and overall dietary context are likely to influence any effect on development.
Although the magnitude of the observed differences in IQ is relatively small—around one to two points—the researchers emphasize that even modest shifts in cognitive outcomes can be meaningful at the population level. Early childhood is a period of rapid brain growth and high nutritional demand, and consistent access to nutrient-dense foods supports the development of brain tissue and function during that formative time.
Dr. Lisa Smithers, who led the study, highlights the practical implications: choosing nutritious feeding patterns from six to 24 months can have measurable, if modest, effects on later cognitive performance. The research reinforces public health messages that emphasize breastfeeding when possible and the introduction of varied whole foods such as vegetables, fruits, legumes and dairy during the transition to family foods.
This study contributes to a growing body of evidence linking early diet and later cognitive outcomes. It does not claim that diet is the sole or dominant factor determining IQ—many influences, including family environment, education, genetics and socioeconomic factors, also play major roles. Rather, the findings support the idea that diet is one modifiable factor among several that can influence child development and that improving early nutrition may yield long-term benefits for cognitive health.
Parents and caregivers can draw practical lessons from this research: prioritize nutrient-rich foods during the first two years, limit frequent exposure to sugary and highly processed snacks and beverages, and consider breastfeeding where possible and appropriate. Health professionals and policymakers may use results like these to guide recommendations and programs aimed at improving infant and toddler nutrition.
Notes about this IQ research
Contact: Dr. Lisa Smithers – University of Adelaide
Source: University of Adelaide press release
Image source: Vegetables image adapted from an image by Elina Mark (Own work) shared under CC-BY-SA-3.0 via Wikimedia Commons.
Original research: “Dietary patterns at 6, 15 and 24 months of age are associated with IQ at 8 years of age” by Lisa G. Smithers et al., European Journal of Epidemiology (2012), Volume 27, Number 7, pages 525–535; DOI: 10.1007/s10654-012-9715-5.