Dogs fed plant-based diets could live up to 18 months longer than those on meat-based alternatives, a new study from North America has suggested.

Scientists from the University of Guelph collected more than 1,400 questionnaires from dog owners across Canada and the US for the study, which has been published in the journal Research in Veterinary Science. It found that dogs on plant-based diets had a mean lifespan of 14.1 years, based on 103 responses, compared to a mean 12.6 years for those on meat-based diets, based on 907 responses.   (Read full published article here)

Since these findings, the BVA, which has so far resisted calls to recommend vegetarian or vegan diets for dogs, said it is planning to review its position.

Old Irish Setter

Comparison

A slightly higher proportion of plant-fed dogs (4.2%) was reported by owners to be obese compared to 3.4% of the meat-fed cohort, while the proportion of dental disease reports in both groups was 19%.

But several different health disorders were also less frequently reported among plant-fed dogs than their meat-fed counterparts, including dermatopathy (19%; 20%), endocrinopathy (1.5%; 2.4%), gastrointestinal and hepatic diseases (7.8%; 15%), neurological and ophthalmic conditions (3%; 4.3%) and renal disease (0%; 1.8%).

Receptive

The study urged vets to be more receptive to owners’ observations after respondents reported more positive views of the health of plant-fed dogs than those on a meat-based diet, based on seven indicators of wellness including appearance and behaviour, as well as instances of vomiting, inactivity or contact avoidance.

It said: “This perception must be considered by veterinary practitioners when diet-related health risks or benefits are discussed with dog owners – particularly as dog owners feeding plant-based may seek information regarding dog diet from alternative resources. Further prospective research is warranted to determine if (plant-based diets) alter canine health.”

The findings follow a recent peer-reviewed study in the Plos One journal, which suggested dogs fed vegan diets were healthier and required fewer veterinary interventions, based on analysis of more than 2,500 animals.

‘Very exciting’

Andrew Knight, one of the authors of that paper, said the evidence in favour of vegan diets for dogs is now overwhelming, with seven out of eight published studies advocating their use.

He described the Guelph study’s findings on lifespan as “very exciting” and renewed his call for opponents of the approach to provide evidence to support their alternative stance.

Prof Knight said: “Further research would always be helpful, but is not needed to form a reasonable, evidence-based position on this issue. That will not be accepted by those with entrenched opposition to vegan diets, but such opposition is not evidence-based, nor in the best interests of dogs.”

Essential nutrients

Until now, the BVA’s position has been not to recommend either a vegetarian or vegan diet for dogs. The body has argued that such an approach, though theoretically possible, makes it easier for owners to get the balance of essential nutrients wrong in the food they give to their pet. An initial statement in response to the latest study said that remained the organisation’s position and suggested further studies of whether non-animal protein sources could meet dogs’ long-term needs were required.

But BVA president Justine Shotton later added: “We recognise that there is growing interest in this area – particularly from a sustainability perspective – and that this goes hand in hand with a growing body of scientific research.

“We are really open to exploring how this evidence base could support vegan diets as a more sustainable option and plan to review this in depth in due course.”

Criticism

The BVA has previously faced criticism for emphasising a lack of evidence on the lifetime effects of vegan diets, which its opponents claimed was a standard not required of any other dietary programme.

Meanwhile, some critics of vegan diets have claimed findings that are based on the responses of owners cannot be considered scientifically objective. But Prof Knight, from the Centre for Animal Welfare at the University of Winchester, said greater levels of funding would be needed to conduct studies where dogs’ diets were compared without owners’ input.

He said he and others would be interested in undertaking such a project, but maintained that researchers had made the best possible use of the resources offered to the area to date.

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