Soy in Baby Formula
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Soy Baby Formula and Severe Menstrual Cramps

Adapted from Soy-based infant formula feeding and menstrual pain in a cohort of women aged 23–35 years published in November 2018 issue of Human Reproduction.

Menstrual pain (dysmenorrhea) is characterized by menstrual bleeding-related abdominal pain, cramping, or a backache. It is considered the most common menstrual complaint, with studies reporting a prevalence of 60% among reproductive-age women. Menstrual pain can have a substantial impact on quality of life, affecting school performance, work productivity and relationships.

In a study by the National Institute of Environmental Health Sciences, 1,553 young women (18-22 years) with the help of their mothers were asked whether they had been fed soy formula as a baby, how long they had been fed soy, and whether the soy was introduced during the first two months after they were born.

The scientists observed that soy formula feeding during infancy was associated with several indicators of severe menstrual pain in reproductive age women. These included:

  • 50% increased risk of moderate to severe menstrual discomfort with most periods during adulthood.

  • 40% increased risk of having to use hormonal contraception to alleviate menstrual pain.

Feeding infant girls baby formula containing soy may lead to substantial exposure to phytoestrogens (plant compounds that are structurally similar to estrogen) during a critical window of female reproductive system development.

The concentration of phytoestrogens in the urine of soy formula-fed infants was shown to be 500 times that of cow’s milk formula-fed infants. Vaginal tissue alterations indicative of an estrogenic response have been observed in infant girls exclusively fed soy formula.

This study suggests that soy formula feeding during infancy is associated with menstrual pain in adulthood, and it adds to the growing body of literature from animal and human studies on the disruptive effects of early-life exposure to soy formula on reproductive system development that persist into adulthood.

December 2018


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