Project Summary/Abstract
Expanded cannabis legalization nationwide and increased use among reproductive-aged women have exposed
gaps in our scientific knowledge on whether and/or how cannabis use during lactation affects human milk
composition. Human milk is considered optimal nutrition for infants for the first 6 months postpartum. Whereas
recent evidence has shown that cannabinoids transfer into human milk, there is only one preliminary study that
indicates that cannabis use may be associated with changes in milk factors and no studies that assess how
cannabis use patterns or cannabinoid concentrations in milk impact holistic milk composition. This lack of
knowledge is particularly concerning as 1) human milk is frequently the sole source of infant nutrition in the first
months of life; 2) cannabinoids are lipophilic and, given the high lipid content of the mammary gland and human
milk, both may be repositories for these compounds, and 3) delta-9-tetrahydrocannabinol (∆9-THC) levels in
cannabis products have increased in the past several decades, suggesting that the milk of mothers who use
cannabis and their recipient infants may be exposed to higher doses of cannabinoids than ever before. The
overall objectives of this project are to 1) characterize and compare holistic human milk composition
(metabolome, lipidome, and proteome profiles) among mothers who use cannabis and those who do not use
cannabis and 2) investigate the relationships between and among human milk cannabinoid concentrations,
maternal characteristics, cannabis use patterns, and milk metabolome, lipidome, and proteome profiles among
breastfeeding women who use cannabis. Our central hypotheses are that 1) cannabis use alters human milk
metabolome, lipidome, and proteome profiles, 2) cannabinoid concentrations in milk are related to milk
metabolome, lipidome, and proteome profiles, and 3) differences in pre- and postnatal cannabis use patterns
and selected maternal characteristics [e.g., body mass index (BMI), time postpartum] are related to variation in
milk metabolome, lipidome, and proteome profiles, even when controlling for cannabinoid concentrations in milk.
To test these hypotheses, we will compare bioarchived milk samples from 20 healthy women (≤ 6 months
postpartum) who use cannabis (≥ 1x weekly) and 20 healthy women who do not use cannabis. We will employ
a multi-omics approach to characterize and understand holistic milk composition (i.e., metabolome, lipidome,
and proteome profiles). Results from this work are expected to provide data on whether cannabis use during
lactation impacts human holistic milk composition and, importantly, constitute the foundation for a NIH R01
proposal. It also takes the initial steps toward providing mothers and healthcare providers data to enable more
informed advice and evidence-based decisions during lactation.