# Systematic Review and Meta-Analysis of Quality Claims Associated with Fresh Pet Food: Evaluating Scientific Evidence for Additives, Ingredient Quality, and Effects of Processing in Pet Nutrition

## TL;DR

This study reviews scientific evidence behind claims made by fresh pet food companies about additives, ingredient quality, and processing effects on pet health.

## Contribution

The paper provides a systematic review and meta-analysis of three key quality claims in the fresh pet food market, offering evidence-based insights for consumers and professionals.

## Key findings

- Approved additives and preservatives within regulatory limits do not appear to harm pets.
- Processing effects on digestibility and nutrient content depend on ingredient type and method, not just intensity.
- Evidence for human-grade ingredients being superior is limited due to methodological issues in studies.

## Abstract

Pet owners today face an overwhelming array of dietary options for their companions, from grain-free kibble to fresh-frozen meals and boutique brands, each marketed with claims of superior nutrition and improved health outcomes. Understanding these options and their consequences on pet health is essential for both consumers making purchasing decisions and veterinary professionals recommending dietary formats. Beyond basic nutritional adequacy, consumers must evaluate product-related factors including the presence of additives, preservatives, and fillers; the use of human-grade ingredients; processing temperatures and methods; whole versus processed ingredients; and overall nutrient integrity. This systematic review examined three prevalent quality claims made by leading fresh pet food companies: that additives and preservatives are harmful, that human-grade ingredients offer superior safety and nutrition, and that whole ingredients provide greater health benefits than processed alternatives. We assessed the scientific evidence supporting each claim and evaluated their potential health impacts on dogs and cats.

The fresh pet food market has experienced substantial growth, with manufacturers making quality claims that influence consumer purchasing decisions and veterinary recommendations. This systematic review evaluates the scientific evidence supporting three prevalent claims associated with fresh pet food: that additives, preservatives, and fillers are harmful to pet health; that human-grade ingredients provide superior safety and nutrition compared to feed-grade ingredients; and that whole ingredients offer health advantages over processed ingredients. A comprehensive literature search across the SCOPUS, PubMed, and EBSCO databases identified 4888 potential studies. Following systematic screening and quality assessment, 121 studies met inclusion criteria for analysis. Bayesian meta-analyses of additives (n = 60 studies) and preservatives (n = 39 studies) revealed pooled risk differences of 0.0006 and 0.0003, respectively, with Bayes factors strongly supporting null hypotheses of no adverse effects within regulatory limits. Random-effects meta-analyses of processing effects on ingredient digestibility (n = 102 comparisons, SMD = 1.971, p = 0.005) and nutrient content (n = 137 comparisons, SMD = 1.405, p < 0.001) demonstrated significant heterogeneity, with outcomes highly dependent on ingredient type and processing method rather than processing intensity. Human-grade versus feed-grade ingredient comparisons (n = 6 studies) showed methodological limitations and high risk of bias, preventing definitive conclusions. Current evidence does not substantiate claims that approved additives and preservatives cause harm when used within AAFCO guidelines. Processing effects vary substantially by ingredient matrix and method, with both beneficial and detrimental outcomes observed. This review identifies critical research gaps and provides recommendations for evidence-based marketing practices, targeted research priorities, and informed decision-making by industry professionals and consumers.