Infant diet quality index predicts nutrients of concern and ultra-processed food intake in low-income children in the United States.

Background: Diet quality during infancy can influence nutrient intake and ultra-processed foods (UPFs) consumption throughout later childhood.

Objectives: This study investigated the predictive validity of Infant Diet Quality Index (IDQI) scores from 0 to 1 y of age and consumption of select nutrients and UPFs at different time points in low-income children aged 2-5 y.

Methods: Dietary surveys and 24-h dietary recalls collected between ages 0 and 12 months from 2613 Special Supplemental Women, Infants, and Children Infant Toddler Feeding Practices Study-2 participants were used to assess infant diet quality by final IDQI score ranging from 0 (nonadherence to dietary guidelines) to 1 (complete adherence to guidelines). Single 24-h recalls collected across multiple time points per child aged between 2 and 5 y were used to determine nutrient intakes: vitamin B12 (μg), vitamin D (μg), calcium (mg), iron (mg), zinc (mg), potassium (mg), saturated fat (g), dietary fiber (g), and added sugars (g). Likewise, Nova was used to classify foods (to estimate the percentage of energy from foods) by level of industrial processing at each point in time across ages 2-5 y. Survey-weighted regression analyses estimated associations between total IDQI score and nutrient intake and percentage of energy consumption from each Nova food group at each age between 2-5 y.

Results: IDQI scores based on diet quality from 0-1 y of age were positively associated with children's dietary fiber and potassium intake at ages 2-5 y. Additionally, IDQI was negatively associated with added sugar intake. No associations were observed between IDQI and saturated fat consumption. IDQI scores at age 1 were positively associated with the percentage of energy attributed to unprocessed/minimally processed foods (20%-23%) and negatively associated with UPF consumption at ages 2-5 y (-24% to -29%).

Conclusions: IDQI predicts intake of select nutrients and UPF consumption among low-income US children aged 2-5 y.This trial was registered at https://clinicaltrials.gov/study/NCT02031978 as "Feeding My Baby - A National WIC Study," NCT02031978.