The investigators' over-arching hypothesis is that mechanical and compositional properties of chia seeds supplemented during lactation diminish obesity-induced intestinal inflammation and barrier dysfunction. The investigators hypothesize these changes will result in: 1) reduced maternal systemic inflammation (serum CRP and IL-6) and increased gut microbial diversity and richness, 2) reduced HM fat and inflammatory markers, metrics the research team have demonstrated differ in tandem with maternal metabolic health and 3) improved infant growth/body composition. To test these hypotheses, investigators will evaluate chia seed supplementation during lactation in a 6wk multi-site pilot RCT (Aim 1) and through translational studies using human enteroids (Aim 2).

Childhood metabolic disease has become a progressively serious global health challenge. The investigators' preliminary data reveal maternal metabolic dysfunction and poor diet are associated with increased human milk fat, proinflammatory markers, and altered microbiota, potentially contributing to transmission of metabolic susceptibility to offspring, while their studies in animal models demonstrate associations between milk composition and offspring metabolic health may be a mechanism by which lactational programming dictates offspring metabolic susceptibility. The investigators' long-term goal is to identify easy-to-implement maternal dietary interventions to optimize offspring development and prevent childhood metabolic disease. Chia seeds contain fiber, polyphenols, -3 polyunsaturated fatty acids, and bioactive peptides, and, through a multitude of mechanisms, improve the metabolic health of those with type 2 diabetes and obesity. This project will test the hypotheses that (Aim 1) 6wks of chia seed supplementation will impact obese, lactating mothers' metabolic health, milk composition, and infant growth, and (Aim 2) chia seed polyphenols and bioactive peptides will reduce permeability, inflammation, and oxidative stress, as well as ATP generating metabolism, in human enteroids, at homeostasis and during in vitro lipotoxicity. Further, investigators will utilize a luciferase-reporter assay to evaluate whether chia seed bioactives function via activation of extraoral bitter taste receptors. Successful completion of this project will inform future maternal lactational interventions that are practical and effective in reducing offspring susceptibility to childhood obesity and diabetes, supporting feasibility for a multidisciplinary, collaborative grant focused on the metabolic health of mother-infant dyads.

Inclusion Criteria:

• pre-pregnancy BMI >25 kg/m²
• Maternal age 18 - 45 years at time of delivery
• Singleton pregnancy
• Vaginal delivery
• Intention to breast feed for at least three months
• No prescription medications that may interfere with gut microbiome
• Not taking antibiotics for ≥ 1 week prior to each visit
• No chia seed supplements during pregnancy

Exclusion Criteria:

• Inability to understand English
• Preterm or post-term birth (gestational age <37 or >42 weeks)
• Congenital or other defect or medical condition that would affect the mother's ability to produce milk or the infant's growth or ability to breastfeed
• Infant eating more than 12 ounces of any liquid other than breast milk in the two weeks prior to each study visit
• Taking Antibiotics (all), Proton pump inhibitors/H2 blockers, Metformin, NSAIDs, Statins, SSRIs and tricyclic antidepressants

Female