In recent years, the pet food industry has witnessed a significant shift as more dog owners consider plant-based diets for their canine companions. This trend, driven by environmental concerns, ethical considerations, and health perceptions, raises critical questions: Can plant-based dog foods truly meet the rigorous nutritional standards necessary for maintaining canine health? A groundbreaking study conducted by Rebecca Brociek and colleagues at the University of Nottingham provides a nuanced examination of this emerging market segment by analyzing commercially available dry dog foods sold in the United Kingdom. Published in the open-access journal PLOS One on September 3, 2025, the research scrutinizes the nutritional composition of plant-based, meat-based, and specialized veterinary dry dog foods, revealing surprising insights into their adequacy and shortcomings.
Dogs, evolutionarily classified as omnivores, possess the physiological flexibility to derive essential nutrients from a mixed diet of animal and plant origin. This omnivorous capacity underpins the appeal of plant-based dog food as a potentially viable alternative to traditional meat-based formulations. Nonetheless, the complexity of canine nutrient requirements—encompassing macronutrients such as proteins and fats, as well as micronutrients including vitamins and minerals—necessitates rigorous evaluation of any diet labeled as “complete.” The United Kingdom’s Food Standards Agency and the European Pet Food Industry Federation (FEDIAF) delineate stringent guidelines to ensure that marketed dog foods supply the full spectrum of essential nutrients to support adult canine health.
Addressing the paucity of data on the nutritional integrity of plant-based dog foods, Brociek et al. embarked on an observational study involving 31 dry dog food products widely available in the U.K.—comprising 19 meat-based formulas, 6 plant-based options, and 6 veterinary-specific products designed to be protein-restricted for canines suffering from renal conditions. Each product bore the “complete” designation, implying an assurance of meeting or exceeding FEDIAF recommendations. Nutrient analysis included quantification of proteins, amino acids, minerals, and vitamins, providing a comprehensive biochemical profile to benchmark against established nutritional targets.
Results revealed that meat- and plant-based dog foods exhibited broadly similar profiles in total protein content and amino acid availability. However, a critical divergence emerged concerning specific micronutrients—most notably iodine and B-vitamins—where the plant-based formulations frequently failed to meet the FEDIAF minimums. Iodine, integral for thyroid hormone synthesis, plays a pivotal role in metabolic regulation; deficiencies can precipitate hypothyroidism with deleterious systemic effects. B-vitamins, a complex group involved in myriad enzymatic processes and energy metabolism, are similarly essential for maintaining neurological and hematopoietic health. The study suggests that the identified gaps in these nutrients could be addressed either through targeted supplementation or reformulation strategies adopted by pet food manufacturers.
Perhaps most strikingly, none of the evaluated dog foods—irrespective of their core ingredient base—fulfilled the full suite of FEDIAF criteria across all necessary nutrient categories. While all products generally met vitamin D standards, only a subset satisfied recommendations for essential amino acids, minerals, and B-vitamins. The veterinary diets, designed for compromised kidney function and consequently lower protein levels, underperformed particularly in essential amino acid content. Given that dogs cannot synthesize these amino acids endogenously, insufficient provision through diet risks malnutrition and functional decline. These findings underscore systemic challenges in formulating nutritionally complete canine diets, extending beyond the binary of plant versus animal ingredients.
The implications of these results are manifold. For dog owners, they raise awareness about the potential nutritional limitations of commercially available “complete” diets—particularly those marketed as plant-based alternatives. While convenience and ethical considerations drive interest in plant-based pet nutrition, ensuring that these diets meet physiological demands remains paramount to prevent inadvertent deficiencies. The researchers emphasize the practicality of supplementation to correct for identified micronutrient shortfalls, yet advocate for proactive measures by manufacturers to refine formulations in alignment with regulatory standards.
Moreover, this study highlights the necessity for ongoing, independent nutritional audits of pet foods, especially as novel formulations penetrate the market. Since the nutritional requirements of dogs vary according to life stage, physiological status, and health conditions, future research must expand the scope to encompass growing puppies and the variable biochemistry that influences nutrient bioavailability. Digestion and absorption kinetics, for example, could differ markedly depending on raw material composition and processing methods, thus impacting the actual nutrient uptake available to the dog beyond nominal label declarations.
As Brociek reflects, the common assumption that dog health hinges intrinsically on meat consumption warrants reconsideration. “What dogs really need are the right nutrients,” she concludes, emphasizing that both plant and meat-based diets exhibited gaps, challenging simplistic dichotomies within canine nutrition debates. The study aligns with similar comparative analyses from Brazil and Canada, suggesting a global pattern of complexities rather than outright superiority of any single diet type. Such findings pave the way for nuanced conversations about pet food innovation, animal health, and ethics.
Nutritional science and pet epidemiology experts alike will find value in this data-driven approach, offering empirical support for evidence-based recommendations tailored to individual pet needs and owner preferences. With the pet population continuing to grow and diet-related health issues garnering increased scrutiny, establishing transparent, verifiable standards for pet food composition is more critical than ever. Brociek and her team’s work sets a precedent for systematic examination of diet quality and signals areas where enhancement is both necessary and feasible.
To this end, technological advancements in nutrient profiling and formulation will likely play a decisive role in the future landscape of canine nutrition. The integration of precise biochemical assays, coupled with robust regulatory frameworks, can potentially elevate plant-based dog foods to parity with traditional options in both safety and efficacy. Meanwhile, pet owners and veterinarians must remain vigilant consumers and advisers, attuned to emerging data and ready to advocate for diets that prioritize complete and balanced nutrition.
In sum, the nutritional landscape of commercially available dry dog foods in the U.K., whether plant-based or meat-based, is marked by incomplete adherence to industry standards. This study’s revelations suggest that nutrition-focused innovation and rigorous quality control are essential in improving pet health outcomes. As the conversation surrounding plant-based diets for dogs gains momentum, this research offers a sobering reminder: the nutrient composition—not the ingredient source—is the ultimate determinant of canine wellbeing. Both consumers and producers share the responsibility to ensure that “complete” truly means complete.
Subject of Research: Animals
Article Title: Nutritional analysis of commercially available, complete plant- and meat-based dry dog foods in the UK
News Publication Date: 3-Sep-2025
Web References: http://dx.doi.org/10.1371/journal.pone.0328506
References: Brociek RA, Li D, Broughton R, Gardner DS (2025) Nutritional analysis of commercially available, complete plant- and meat-based dry dog foods in the UK. PLoS One 20(9): e0328506. https://doi.org/10.1371/journal.pone.0328506
Image Credits: MART PRODUCTION, Pexels, CC0
Keywords: plant-based dog food, canine nutrition, pet food analysis, essential amino acids, vitamin deficiencies, phosphorus, iodine, B-vitamins, FEDIAF guidelines, dry dog food, veterinary diets, nutritional completeness, pet health
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