Soy infant formula associated with a risk of seizures in children with autism

Please  note that this is a retrospective study. Confirmation is needed. Close surveillance is advised in high risk babies. JR 

PLoS One. 2014 Mar 12;9(3):e80488. doi: 10.1371/journal.pone.0080488. eCollection 2014.

Soy infant formula and seizures in children with autism: a retrospective study.

Westmark CJ.

Author information

Abstract

Seizures are a common phenotype in many neurodevelopmental disorders including fragile X syndrome, Down syndrome and autism. 

We hypothesized that phytoestrogens in soy-based infant formula were contributing to lower seizure threshold in these disorders. 

Herein, we evaluated the dependence of seizure incidence on infant formula in a population of autistic children. Medical record data were obtained on 1,949 autistic children from the SFARI Simplex Collection. An autism diagnosis was determined by scores on the ADI-R and ADOS exams. The database included data on infant formula use, seizure incidence, the specific type of seizure exhibited and IQ. Soy-based formula was utilized in 17.5% of the study population. Females comprised 13.4% of the subjects.

 There was a 2.6-fold higher rate of febrile seizures [4.2% versus 1.6%, OR = 2.6, 95% CI = 1.3-5.3], a 2.1-fold higher rate of epilepsy comorbidity [3.6% versus 1.7%, OR = 2.2, 95% CI = 1.1-4.7] and a 4-fold higher rate of simple partial seizures [1.2% versus 0.3%, OR = 4.8, 95% CI = 1.0-23] in the autistic children fed soy-based formula. 

No statistically significant associations were found with other outcomes including: IQ, age of seizure onset, infantile spasms and atonic, generalized tonic clonic, absence and complex partial seizures. Limitations of the study included: infant formula and seizure data were based on parental recall, there were significantly less female subjects, and there was lack of data regarding critical confounders such as the reasons the subjects used soy formula, age at which soy formula was initiated and the length of time on soy formula.

 Despite these limitations, our results suggest that the use of soy-based infant formula may be associated with febrile seizures in both genders and with a diagnosis of epilepsy in males in autistic children. Given the lack of data on critical confounders and the retrospective nature of the study, a prospective study is required to confirm the association.

"Seizures are a serious and common phenotype in many neurological disorders besides autism and epilepsy including fragile X syndrome[25], Alzheimer's disease [26], Down syndrome [27], tuberous sclerosis [28] and Rett syndrome [29]. According to the Epilepsy Foundation, ten percent of the American population will experience a seizure in their lifetime; however, the underlying molecular mechanisms that cause seizures are not well understood. Seizure severity is likely a combination of both genetic and environmental factors. Our hypothesis is that the effects of an underlying genetic mutation that lowers seizure threshold may be exacerbated, for example, by dietary exposure to high concentrations of phytoestrogens. This would be particularly significant for individuals whose diet is solely soy-based, for example, soy-based infant and gastric tube feeding formulas. Nearly a quarter of infant formulas are soy-based; yet, there is no epidemiological data examining the incidence of seizures, autism, or the severity of fragile X syndrome and other developmental disorders in children fed soy-based versus non-soy-based formula."