Research bolsters the evidence for health benefits of isoflavone-rich soy foods
A recent study discovered that school-aged children who consumed higher amounts of isoflavones from soy foods demonstrated improved cognitive abilities and attention. These results open the door for further research into how soy foods can beneficially influence children’s cognitive development.
Isoflavones are naturally occurring compounds found in various plants, particularly soybeans and soy products. Although previous research in adults has suggested that soy isoflavones can improve memory, the benefits haven’t been studied well 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 adds evidence of the importance of nutrients found in soy foods for childhood cognition.”
Bristina presented the findings at NUTRITION 2024, the flagship annual meeting of the American Society for Nutrition.
To examine the potential benefits of soy isoflavones, the researchers examined previously available data from a cross-sectional study that included 128 children ages 7 to 13. They used information from 7-day diet records to calculate each child’s average dietary intake, including the amounts of macronutrients, micronutrients, vitamins and isoflavones consumed. To assess the children’s general intellectual ability, the researchers used a set of pencil and paper tests adjusted for grade level. They also measured attentional abilities using a computerized task known as the flanker task while electroencephalographic (EEG) activity was recorded and used to measure information processing speed and attention.
Findings and Implications
“No other studies have examined the association between soy isoflavones and attentional abilities using EEG or similar measures to record electrical activity generated by the brain,” said Bristina.
Overall, the analysis revealed that the children in the study tended to consume low amounts of isoflavone-containing soy foods. However, those who consumed more soy foods showed faster responses during the attentional tasks and exhibited faster processing speed. No association was observed 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 says that snacks like roasted edamame, soynuts, or soymilk are a good way 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 find out more, the research team recently began a clinical trial examining the effects of soy foods on thinking abilities, sex hormones, metabolic health, and gut health.
Reference: “Soy Isoflavone Consumption Is Associated With Greater Attentional Inhibition Among School-Aged Children” by Ajla Bristina, Ilber E. Manavbasi, Laura M. Rosok, Corinne N. Cannavale, Shelby A. Keye and Naiman A. Khan, 2 July 2024, NUTRITION 2024.