Abstract
Background: Household food insecurity is defined in New Zealand as a ‘limited or uncertain availability of nutritionally adequate and safe foods or limited ability to acquire acceptable foods in a socially acceptable way’. It is a serious and longstanding public health concern in New Zealand but has received greater public attention following the cost-of-living crisis experienced in New Zealand in recent years. Infants are entirely dependent on their parents or caregivers for food, and it is important that they receive adequate nutrition to meet the demands of growth and development in later infancy. Evidence suggests that household food insecurity is associated with a lower prevalence of exclusive breastfeeding and early introduction of complementary feeding – practices that are the subject of current infant feeding guidelines. The novel complementary feeding practices of commercial baby food pouch use and baby-led weaning have grown in popularity in recent times but have been accompanied by nutritional concerns. Surprisingly, no studies have investigated their use in food insecure families anywhere in the world. More generally, while food intake has been measured in food insecure infants in New Zealand, finding a lower consumption of fruits and vegetables, no studies have measured nutrient intakes. Likewise, the potential impact of food insecurity on infant obesity, which is a controversial issue, has not been investigated in infants living in food insecure New Zealand households.
Food insecurity is presented as a category for measurement in quantitative studies, but it is also a human experience. Within families, mothers may be disproportionately burdened by food insecurity owing to their social roles as primary caregivers and food providers for the household. Very little is known about mothers’ experiences of feeding an infant in the context of food insecurity in New Zealand.
Aims: The overall aim of this thesis was to explore infant feeding in food insecure households in New Zealand. The quantitative aim of this thesis was to define and describe the extent of food insecurity in New Zealand families with infants from 7.0 to 9.9 months of age, then to investigate associations between household food security status and infant feeding practices, infant nutrient intakes, types of complementary foods consumed, and body mass index (BMI) z-score. The qualitative aim of this thesis was to explore the experience of feeding an infant in the context of household food insecurity from the perspectives of New Zealand mothers with infants.
Methods: The quantitative component of this thesis uses data from the First Foods New Zealand (FFNZ) study. The FFNZ study is a multi-centre, observational, cross-sectional study investigating infant feeding, nutrition, and health in 625 infants 7.0–9.9 months of age in New Zealand. Household food insecurity was measured using a New Zealand-specific validated questionnaire administered in person, the ‘food security measurement tool for New Zealand households’. Households were classified into one of three categories of food insecurity: food secure, moderately food insecure, or severely food insecure. Demographic characteristics of caregiver-infant dyads, and data on infant feeding practices were collected via questionnaire. Two 24-hour diet recalls were used to assess infant nutrient intakes. Breast milk intakes were calculated in a subsample of infants using the stable isotope deuterium oxide ‘dose-to-mother’ technique. Data on dietary supplement use were collected via questionnaire. Consumption of complementary foods was investigated using food groups based on the Otago New Zealand Food Groups 2023 system. Body mass index z-scores were calculated using World Health Organization Child Growth Standards.
For logistic reasons, the qualitative ‘Families Accessing Food’ study was carried out before the findings of the quantitative component were available. Individual, semi-structured interviews were used to explore infant feeding in the context of food insecurity from the perspectives of 15 food insecure mothers who had participated in the FFNZ study in Dunedin, New Zealand. The research was located in an interpretive paradigm. Interview transcripts were analysed thematically using Braun and Clarke’s ‘reflexive thematic analysis’.
Results: In total, 25.0% of families with infants experienced a degree of food insecurity (17.6% moderate; 7.4% severe). Caregivers of Māori or Pacific ethnicity, of younger ages, on leave from work or not in work, living in larger-sized households, or for whom school (primary or secondary) was their highest level of education, were more likely to be food insecure. The proportion of severely food insecure caregivers exclusively breastfeeding to around 6 months of age was slightly over half that of food secure caregivers (24% vs. 40%), although the difference was not statistically significant (p=0.061). Moreover, severely food insecure caregivers introduced complementary foods significantly earlier (4.8 months vs. 5.2 months) than moderately food insecure or food secure caregivers, with 46% doing so before 5 months of age. At the mean age of 8.4 months, the odds of frequent use of commercial baby food pouches in severely food insecure caregivers were more than five times those of food secure caregivers. No significant differences were observed in the use of baby-led weaning between the groups.
The nutrient intakes of food insecure infants were similar to those of food secure infants, aside from slightly higher intakes of free sugars and added sugars in food insecure infants. Irrespective of food security status, intakes of key nutrients investigated (protein, total fat, total carbohydrate, calcium, zinc, vitamin B12, and vitamin C) appeared to be adequate. Severely food insecure infants were significantly less likely to consume ‘fruits’ and ‘vegetables’ outside of commercial infant foods but were significantly more likely to consume ‘commercial infant wet foods’, all of which are fruit and vegetable-based foods. No evidence was found of a difference in mean BMI z-score in food insecure infants compared with food secure infants, and most infants were of a healthy weight.
Three themes and one subtheme were generated in the qualitative Families Accessing Food study: 1) Food purchasing strategies were used to stretch the money available for food whilst balancing household expenses, 2) The infant’s nutrition was prioritised (subtheme: Breast milk was perceived to support the infant’s nutrition), and 3) Support was valued but asking for money or food could be a disempowering experience.
Conclusion: This thesis reveals that 25% of New Zealand families with infants from 7.0 to 9.9 months of age were experiencing food insecurity. Overall, household food insecurity does not appear to adversely impact the nutrient intakes and weight status of food insecure infants. However, it did appear to reduce caregivers’ ability to meet recommendations for exclusive breastfeeding and age of introduction to complementary foods. Commercial baby food pouches were used in severely food insecure households almost daily. Caregivers reported that pouches offered a convenient way of infant feeding that was often considered to be nutritious, and they may have been an important source of fruits and vegetables. Nutritional and health impacts from the use of commercial baby food pouches, which are being investigated in the wider FFNZ study, could therefore have implications for severely food insecure families, in particular. Future research should explore the barriers to longer durations of exclusive breastfeeding in food insecure families, and investigate the contribution of foods from commercial baby food pouches to nutrient intakes of food insecure infants.
This thesis documents mothers’ resourcefulness, skills, and persistence in navigating food insecurity to feed their infants. Their narratives demonstrated the ‘work’ that food provision in a food insecure context creates. Behind their actions was a strong sense of accountability for ensuring their infants had access to a nutritious diet, and they considered that their infants were thriving. This thesis shows that despite the hardships faced by food insecure families, caregivers are managing to provide their infants with a nutritionally adequate diet. It reassuringly suggests that food insecurity does not compromise the diets of New Zealand infants. However, this does not minimise the observation that a substantial proportion of New Zealand families with infants are experiencing food insecurity, and that mothers are making sacrifices to ensure that their infants are well fed. Understanding the underlying drivers of food insecurity in this population group, and the impact on mothers of their efforts to protect infant nutrition, will be key to guiding responses that support families raising New Zealand’s future generations to flourish.