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Session: Formulating for the Future: Food Science Approaches to Improving Human Nutrition (Oral 16)

(OR16-01-23) Risk and Benefits of Milk Fortification With a Lower Dose of Iron: Insights From a Piglet Model

Monday, July 24, 2023
8:00 AM – 8:12 AM ET
Location:  Back Bay A
GSRA ELPC

    Presenting Author(s)

  • SN

    Shya Navazesh (she/her/hers)

    Graduate Student
    University of California, Davis
    Davis, California, United States

    Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

    • Co-Author(s)

  • CH

    Carlee Hesler

    University of California, Davis

  • PJ

    Peng Ji, Ph.D.

    Assistant professor
    University of California, Davis
    Davis, California, United States

  • Mary E. Kable, PhD

    Research Scientist/Adjunct Assistant Professor
    University of California, Davis
    Davis, California, United States

Disclosure(s):
Shya Navazesh: No relevant financial relationship(s) with ineligible companies to disclose.
Mary E. Kable, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Objectives: In the U.S., most infant formulas are fortified with more than 30 times the amount of iron in breast milk, raising concerns about iron overexposure. There is limited research on the safety and benefits of lowering the dose of fortification. This study evaluates trace element status and intestinal development in response to a milk replacer fortified with a low, moderate, or high dose of iron in a neonatal pig model.

Methods: Twenty-four piglets (n = 6/treatment) were fed a cow milk replacer fortified with 60 (LI), 120 (MI), 480 mg Fe/kg milk solids (HI) from postnatal day (PD) 2 to 28 or the LI milk replacer with an intramuscular injection of iron dextran (100 mg Fe) on PD3 and PD15 (INJ). Piglets were individually housed and fed at 220 mL milk · (day · kg body weight) -1 . Milk was delivered to each piglet in 14 meals through a programmable automatic feeding system. Body weight was recorded every other day. Fecal and blood samples were collected weekly. Pigs were orally gavaged with IdU solution 24 hours before euthanasia to assess the activity of intestinal stem cells. Trace minerals in tissues, cecal contents, and feces were analyzed via inductively coupled plasma atomic emission spectroscopy. The cecal and fecal microbiome will be analyzed using 16S rRNA sequencing.

Results: Growth measured as body weight was not different among treatments. The LI pigs had lower (P < 0.05) hemoglobin (Hb) which was at the borderline of anemia on PD 7, 21, and 28, while Hb was not different among the other groups. In comparison with the other groups, HI pigs had marked iron deposition in the duodenum, liver, and spleen (P < 0.01) but the lowest zinc and manganese in the duodenum. The HI milk
increased cecal iron (P < 0.05) and fecal iron on PD 14 (P < 0.05), 21 (P < 0.07), and 28 (P < 0.01). In the duodenum, MI pigs had the highest expression of DMT1, an iron transporter, while HI and INJ pigs had the lowest DMT1 expression (p < 0.05). The impact of enteric iron overflow on the gut microbiome and intestinal development will be evaluated.

Conclusions: Excess iron fortification in milk formula caused tissue iron overload and compromised zinc absorption. Additionally, HI milk increased iron flow to the large intestine, while moderate reduction of milk iron maintained replete iron status.

Funding Sources: Novo Nordisk Foundation and NIFA Multistate/Hatch Funds