Pros and cons of feeding a raw food diet debated
Speaking at the BVNA Congress in Telford, Dr Marge Chandler, senior lecturer in small animal medicine and clinical nutrition at the University of Edinburgh, began her evidence-based lecture by asking the audience, "Where do most pet owners get their information on feeding pets from?" The consensus view was either from breeders, the pet store or the internet – the latter being identified as being a particularly unreliable source.
Dr Chandler emphasised the importance of using a hierarchical approach to examine the reliability of evidence put forward either for or against the feeding of raw foods. She suggested that the arguments in support of raw diets are usually based on opinion and are not peer-reviewed.
There are many reasons why owners want to use alternative diets – they embrace them as being ‘whole’ or ‘organic’, they may have concerns about additives, palatability, they are attracted by claims for improved health and an idea that these diets are more natural. With regard to this last claim, Dr Chandler pointed out that there are at least 36 differences between the genomes of wolves and dogs, a third of which affect their ability to digest different foods.
There are very few data on the potential risks of feeding raw foods, no lifelong feeding trials, and no comparative studies with commercial diets. Most homemade diets are not complete and balanced, and there is a risk of deficiencies. Compensatory supplementation may then create other imbalances, and human supplements are not always appropriate for animals – especially those for vitamin D – and may result in clinical diseases.
Raw foods regularly test positive for Salmonella, E.coli, Yersinia, Campylobacter and Toxoplasma and, although pets fed them may appear healthy, they can be faecal 'shedders'. This represents potential contamination risks to both pets and animals, especially susceptible individuals and practice staff who handle animals being fed raw food.
Raw food 'treats' – such as pig's ears and hooves – pose a particular risk with respect to salmonellosis. “And we must remember that the assumption is that people will cook the raw meats that they buy for their own consumption and that this will reduce the risk of infection,” Dr Chandler said. “This does not apply in the case of raw foods fed to pets.”
Turning to the subject of dental health and the feeding of raw bones, the speaker said there is some evidence that bones may remove tartar; but they will not affect plaque or reduce periodontitis; but neither will dry foods. Bones increase the risk of fractured teeth, oesophageal and gastrointestinal obstruction or intestinal perforation. They will not supply high levels of calcium; although bonemeal will.
Dogs fed raw bones may develop secondary hyperparathyroidism and it is important to bear this in mind when admitting dogs for dental treatment. Those being fed on raw or homemade diets present a higher risk of complications.
Summarising, Dr Chandler said that in her opinion, the “gold standard are foods that have been produced by companies that undertake lifelong feeding trials. The minimum should be diets that have undergone feeding trials that meet AAFCO protocols and trials”.
Following this lecture, there was a debate and panel discussion on the subject of feeding raw foods, chaired by BVNA president, Fiona Andrew, involving Dr Chandler, Mike Davies, associate professor in small animal clinical practice at the University of Nottingham, Sarah Hormozi from the PFMA and Richard Allport, a referral vet and advocate of feeding raw food from the Natural Medicine Centre in Potters Bar.
The debate was opened by Dr Chandler who gave a very brief reprise of her previous lecture. She said she had three main criteria when assessing foods: they should be complete and balanced, safe and appropriate for the life stage. In her opinion, there are very few trials on raw foods, there is a potential for deficiencies and excesses, increased risk of environmental contamination and problems with raw bones.
Mike Davies observed that animals do not control their intake to maintain a balanced intake. He said he was not aware of controlled studies involving raw diets and that hey have been shown to induce several disease conditions.
He reminded the audience that the FDA has issued a warning to people handling raw foods, especially pregnant women. He pointed out that 60% of chicken is contaminated with Campylobacter and he was emphatic that, despite the claims of some raw food manufacturers, freezing does not kill the major contaminating pathogens such as Salmonella and E. coli.
“It is irresponsible for vets and veterinary nurses to recommend raw foods to their clients,” he concluded.
Sarah Hormozi took the audience through the structure and function of the PFMA and was adamant that member companies took their responsibilities seriously, including the three member companies selling raw foods. She insisted that existing legislation, especially that relating to manufacturing processes and label claims, was adequate, and that policing it was the challenge.
Richard Allport accepted several of the critical technical and clinical points made by Dr Chandler and Mike Davies and admitted that much of what he advocated was by its very nature anecdotal. “Much of veterinary practice is about anecdotes," he declared.
He said that in his experience, raw diets have a particular use clinically in dogs with chronic bowel disease and those with skin allergies, and that he had not seen any of the conditions described by earlier speakers in any of his patients. “They simply get better,” he said.
In response to a question from the audience, he said it was preferable for people who wished to feed a raw food to use a commercial one that is balanced and safe. He reiterated his belief that dogs fed on raw foods are healthier but admitted that his assessment was anecdotal.