Association between parental self-reported knowledge on soy and phytoestrogen and their children's intake of soy-based infant formulae—a cross-sectional study of Israeli parents

Objectives: Though natural phytoestrogen (PE) is a major factor in health authorities’ considerations regarding soy-based infant formula (SBIF), missing their concentrations may interfere with parents' informed decision. Methods: We performed an Internet survey investigating soy-related knowledge of parents. We built multiple logistic regression models adjusted for personal covariates for the association between parental knowledge on PE and children intake of SBIF and checked the effect of having children ≤ 2 years old on this association. Results: We enrolled 304 parents, 48.3% men, mean age 33.8 (standard deviation, SD 4.9), mostly with higher education. Of them, 76% had children under two years of age. Mean parental knowledge on PE was 9.83 (SD 3.28) from 20 possible points. Parental knowledge on PE reduced children's intake of SBIF (odds ratio, OR = 0.85 [95% confidence interval 0.70; 1.02]). Stronger inverse association was found for parents with children ≤ 2 comparing with those with older children (OR = 0.85 [0.67; 1.09] and OR = 0.68 [0.39; 1.18], respectively), although these differences were not statistically significant. Conclusions: Adding PE content to information on SBIF may support informed decision.