Plant-based and meaty kibbles may both lack some important nutrients
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Vegetarian and vegan dog foods just need a few tweaks to make them nutritionally complete diets.
Analyses reveal that meat-free dry kibbles meet dogs’ protein and fat requirements, lacking only sufficient iodine and B vitamins. With supplements or – better yet – improved commercial preparation, plant-based dog food could keep the animals healthy while reducing the environmental impact of the pet food industry, says Rebecca Brociek at the University of Nottingham, UK.
“As long as they’re getting all of the essential nutrients from those ingredients, then the dogs are going to thrive,” she says.
Many vegans and vegetarians who own dogs struggle with the ethics of feeding meat to their omnivore pets, says David Gardner, also at the University of Nottingham. Responding to that concern, pet food manufacturers have started offering plant-based foods to consumers.
Government organisations like the European Pet Food Industry Federation and the Association of American Feed Control Officials require standardised testing of commercial pet foods and additives to ensure they meet nutritional standards. Even so, most pet foods worldwide do not go through robust nutritional testing by independent research teams, says Gardner.
Brociek, Gardner and their colleagues analysed 25 commercial dry foods for healthy adult dogs – 19 containing meat and six based exclusively on plants. Among the latter, two were labelled as vegetarian and four were vegan.
None of the foods met all the official nutritional guidelines for dogs, despite being packaged as nutritionally complete, the researchers say. Even so, all the foods had acceptable concentrations of protein, fatty acids and essential amino acids.
Most – including five of the six plant-based foods – didn’t have enough iodine, but seaweed could easily make up for that deficiency.
Vitamins in general were sufficient across the board, except for vitamin B, which came up particularly short in plant-based foods. Dogs low in vitamin B can have issues with their skin, nerves and digestive systems, so manufacturers should supplement those foods, the researchers say.
The findings point to oversights in all kinds of dog food manufacturing, not just those based on plants, says Andrew Knight at Murdoch University in Australia. “Consumers are expecting that if products are labelled as being nutritionally sound, and that will be true, but clearly it’s not true,” he says.
“I believe a vegetarian diet can be adequate if carefully supplemented with nutrients lacking in plants – as is the case for humans who choose a vegetarian diet,” says Lucia Casini at the University of Pisa in Italy. Owners should avoid making their own plant-based foods for their pets, she adds.
Pet dogs have evolved to be able to eat a wide variety of foods, so feeding them well-balanced, plant-based meals can satisfy their nutritional needs while avoiding the environmental impacts of meat production, like greenhouse gas emissions, says Gardner.
“They’re true omnivores,” he says. “As most Labrador owners – myself included – will tell you, they’ll eat anything.”
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