Abstract:
Objective: Unhealthy diets, which are increasingly comprised of highly processed foods, are a leading cause of ill-health and premature death globally. The aims of this thesis were to identify the most common ingredients in the New Zealand packaged food supply; and how these are linked to a) the level of industrial processing as defined by the NOVA classification system, and b) the healthiness of the products. Design: A systematic literature review and a secondary data analysis using the 2017 Nutritrack supermarket food composition database were undertaken. The systematic review was undertaken across 5 scientific databases in September 2017. The data analysis identified the 20 most common ingredients overall and by level of NOVA processing using extracted ingredient lists of 14,088 food and beverage products. Products were also given a nutrient profiling score using the Food Standards Australia New Zealand Nutrient Profiling Scoring Criterion (NPSC). Statistical analysis was performed to assess whether there was an association between how many of the 20 most common ingredients products contained and how healthy they were according to their nutrient profile score. Findings: The systematic review found no studies that explored the most common ingredients in processed foods by level of processing. However, evidence was found that highly processed foods are associated with less healthy diets containing higher free sugars, trans fats, and energy density, and lower protein, fibre density and nutrient profiles than less processed foods. Salt and sugar were the two most common ingredients overall. Other commonly used ingredients included water, milk, vegetable oils, wheat flour, maltodextrin, glucose syrup and dextrose. These ingredients were similar to the most common ingredients in the Ultra-Processed Food category since this category accounted for 70% of the products surveyed. The Processed Food category contained more ingredients considered to be whole foods. Multiple types of added sugars and sources of sodium were found. The more of the 20 most common ingredients products contained, the less healthy they were. Conclusion: This thesis provides insight into the most common ingredients used in the New Zealand packaged food supply. This is useful for better understanding how consumption of processed foods is affecting the high levels of diet-related non-communicable diseases and to implement strategies to curtail their impact.