A new study found that school-aged children who consumed more isoflavones from soy foods exhibited better cognitive abilities and attention. These findings strengthened the evidence for the health benefits of isoflavone-rich soy foods and paved the way for future research aimed at understanding how soy foods can positively impact children's cognitive development.
Isoflavones are naturally occurring compounds found in various plants, particularly soybeans and soy products. While previous research in adults suggested that soy isoflavones can enhance memory, the benefits had not been well studied in children.
"Soy foods are often not a regular part of children’s diets in the United States," said Ajla Bristina, a neuroscience doctoral student at the University of Illinois Urbana-Champaign. "Our study added evidence of the importance of nutrients found in soy foods for childhood cognition."
Bristina presented the findings at NUTRITION 2024, the annual meeting of the American Society for Nutrition held in Chicago.
To explore the potential benefits of soy isoflavones, the researchers analyzed data from a cross-sectional study that included 128 children aged 7 to 13 years. They used 7-day diet records to calculate each child’s average dietary intake, including macronutrients, micronutrients, vitamins, and isoflavones. The children's general intellectual ability was assessed using pencil and paper tests adjusted for grade level. Attentional abilities were measured using a computerized task known as the flanker task, while electroencephalographic (EEG) activity was recorded to measure information processing speed and attention.
"No other studies had examined the association between soy isoflavones and attentional abilities using EEG or similar measures to record electrical activity generated by the brain," said Bristina.
The analysis revealed that the children in the study generally consumed low amounts of isoflavone-containing soy foods. However, those who did consume more soy foods showed faster responses during the attentional tasks and exhibited faster processing speeds. No association was found between soy isoflavone intake and general intellectual ability.
"The children in our study consumed an average of 1.33 mg of isoflavones per day, which, while relatively low, aligns with previously reported values for the United States," said Bristina. "Soy consumption for individual participants ranged from 0 to 35 mg/day. To put this into perspective, an 8 fl. oz serving of soy milk provides about 28 mg of isoflavones, a serving of tofu provides about 35 mg, and half a cup of steamed edamame provides about 18 mg of isoflavones."
Bristina suggested that snacks like roasted edamame, soynuts, or soymilk are good ways to incorporate more soy into the diet. Tofu, tempeh, or soy-based nuggets are also good options for meals.
"Correlational studies like this are only the first step," said Bristina. "To better understand the effects of eating soy foods on children’s cognitive abilities and the precise amount of isoflavone intake necessary to elicit faster response times will require intervention approaches." To further investigate, the research team recently began a clinical trial examining the effects of soy foods on thinking abilities, sex hormones, metabolic health, and gut health.