Can your pregnancy diet affect how your baby benefits from breastfeeding? Scientists think so.

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Craving peanut butter toast? Scientists say your pregnancy snack might be doing more than satisfying cravings
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If you’re pregnant and craving peanut butter toast, you might be interested in what researchers just found, but before you worry, this isn’t a call to change your diet. It’s simply a fascinating glimpse into how what we eat might “talk” to our baby’s genes.
A new study from Syracuse University, published in Food Science & Nutrition, suggests that mothers who ate both peanuts and peanut butter during pregnancy had children with distinct patterns of DNA methylation, chemical tags that help switch genes on or off, in genes related to brain development and inflammation.
In plain terms? Scientists are beginning to see how a parent’s diet may influence how their child’s body responds to early experiences like breastfeeding.
Related: New research reveals a hidden way breastfeeding may protect moms for decades
What the study found
The research followed 35 mother-child pairs in upstate New York, looking at how peanut or peanut-butter consumption during pregnancy and breastfeeding related to differences in the children’s DNA. The team focused on genes like BDNF (brain-derived neurotrophic factor), which helps guide brain growth, and several genes linked to immune and inflammatory responses.
Among children whose mothers ate both peanuts and peanut butter during pregnancy, longer breastfeeding was linked with increased DNA methylation at certain sites within these genes. By contrast, when mothers ate only peanut butter, longer breastfeeding was tied to decreased methylation at the same sites, potentially signalling different ways those genes might be “expressed.”
As the researchers note, these differences could reflect nutritional variations between whole peanuts and processed peanut butter, such as folate content or allergen levels, which may, in turn, subtly influence gene activity.
Why it matters
“This study doesn’t mean eating peanuts will make your baby smarter or less prone to allergies,” the authors cautioned. Instead, it opens a new window into maternal nutrition and early-life nurturing, in this case, breastfeeding. It may interact through epigenetic processes, the tiny biochemical adjustments that help our genes respond to the environment.
The study was small (only 35 children), didn’t measure serving sizes, and relied on self-reported diet data, so it’s far too early for any recommendations. Still, it adds to growing research showing that pregnancy and lactation are sensitive periods when a parent’s nutrition might help “prime” their baby’s developing systems.
What parents can take away
For most pregnant people, peanuts are considered safe, and even beneficial, unless you have a known allergy. The American Academy of Pediatrics encourages a varied, balanced diet during pregnancy and breastfeeding to support both maternal health and baby’s growth.
So, if you’re a peanut-butter lover, there’s no reason to stop. And if you’re not, there’s no reason to start on account of this study. The takeaway isn’t to overhaul your grocery list, it’s to marvel at the quiet, intricate ways that pregnancy and breastfeeding connect our biology to our children’s beginnings.
In the words of the Syracuse University researchers, “maternal diet may prime the offspring’s epigenome,” shaping how their genes respond to early experiences like breastfeeding. It’s one more reminder that the story of parenthood begins long before birth, and that every small, nourishing act has the potential to echo in ways science is only beginning to understand.
Source:
- Food Science & Nutrition. 2025. “Effects of Maternal Peanut Intake and Breastfeeding Duration on Offspring DNA Methylation.”




















































































