(P30-007-24) Effects of Soy Foods on Childhood Physical and Cognitive Health: The Plants Optimizing Development Study (PODS) Protocol

Objectives: Soy foods are a dietary source of high-quality protein, essential micronutrients, and isoflavones with the potential to contribute to numerous health benefits. Soy isoflavones are phytoestrogens that preferentially bind to estrogen receptor-beta. Previous research has examined the effects of soy isoflavones on health in adults, but comparatively little is known regarding the health effects of isoflavones in childhood. The Plants Optimizing Development Study (PODS) seeks to address this significant research gap. Our central hypothesis is that greater soy isoflavone consumption will not alter sex steroid levels but will be associated with beneficial clinical outcomes on body composition, metabolic health, and the gut-brain axis in pre- and early adolescents.

Methods: Children (N=96) between the ages of 8-11 years will be recruited to participate in a 3-month randomized-controlled clinical trial. Treatment group participants will receive a daily mix of soy foods (e.g. soymilk, soy nuts, tofu, tempeh, edamame) with the target total isoflavone (daidzein, genistein, and glycitein) intake of 50 mg/d. The control group will consume isocaloric soy-free alternatives (e.g., pea milk, chickpeas, fava beans, and plant-based nuggets). The primary outcome will be sex steroids excreted in urine. Secondary outcomes will include Android:Gynoid ratio, bone mineral density (BMD), blood lipids and fasting glucose, fecal microbial α-diversity and Firmicutes:Bacteroidetes ratio, and cognition. Dual-energy X-ray absorptiometry will assess BMD and Android:Gynoid fat ratio. Urine samples will be analyzed for sex steroids using Liquid chromatography–mass spectrometry (LC-MS) and adjusted for urinary creatinine. Stool and venous blood samples will be collected to assess gut microbiota and metabolic marker analyses, respectively. Cognitive assessments will include the Woodcock Johnson Tests of Cognitive Abilities and Academic Achievement IV, i-Position spatial reconstruction memory task, and a modified Eriksen Flanker task.

Results: N/A

Conclusions: Successful completion of the clinical trial will address important knowledge gaps on the effects of prospectively consuming daily soy foods on developmental and health outcomes in school-aged children.

Funding Sources: Soy Nutrition Institute