Researchers at the National Institute of Environmental Health Sciences (NIEHS), Vanderbilt University Medical Center, and the Henry Ford Health System analyzed patient data from African-American women aged 23 to 35 years (N=1553) who were participating in the NIEHS Study of Environment, Lifestyle, and Fibroids (SELF). Women who were ever fed soy formula as infants were 50% more likely to have experienced moderate or severe menstrual discomfort between the ages of 18 and 22. In addition, these women were 40% more likely to have used hormonal contraception to help relieve menstrual pain.
Lead author Kristen Upson, PhD, NIEHS postdoctoral researcher, explained that genistein (a natural component in soy formula) interferes with the development of the reproductive system and that these changes can continue into adulthood. In addition to severe menstrual pain, infant soy formula has also been associated with endometriosis and fibroids. Other data have linked soy formula feeding with changes in vaginal cells, including differences in specific gene activation.
This new study among African-American women supports the body of evidence that suggests soy formula during infancy may have harmful effects on the reproductive system. Previously, this association was identified in a study conducted by researchers from the University of Pennsylvania and the University of Iowa among white young female patients.
According to the American Academy of Pediatrics (AAP), soy formula is not recommended for premature babies. Human milk is the ideal source of nutrition for infants; full-term infants may be given soy formula in rare instances where the child’s body cannot metabolize the sugars in milk or if the family prefers a vegetarian diet.
NIEHS senior scientist, Donna Baird, PhD, stated, “The results of both studies indicate that the findings may apply to all women, but further research is warranted before any changes are made to soy formula feeding recommendations.”
For more information visit academic.oup.com.