GETTING A HANDLE ON GUT FEELINGS
Probiotics show promise in treating animals with anxiety, studies suggest
Whether you are a comfort eater, or someone who can’t eat when they feel stressed, many of us have experienced first-hand how our mood can vastly affect our appetite.
In addition to the effect that stress can have on hunger, research has revealed that what goes on in our gut can also influence how we feel. Scientists refer to this two-way street of communication between the brain and the gut as the “gut-brain axis.”
Research into whether specific probiotics (beneficial bacteria) can affect our mood, and the mechanisms behind these effects, is booming in the human and veterinary medical fields. So far, the results show that the flora present in the guts of humans and animals is indeed correlated with a variety of positive and negative emotional traits, including calmness, anxiety and depression.
The bacteria that are present in our guts can be altered by the ingestion of probiotics, as well as the presence of some diseasecausing bacteria like Campylobacter jejuni, (a common cause of diarrhea and mucus or bloody stools in dogs). Studies have also revealed that the presence of these bacteria can cause mood changes in humans and animals.
The possibility that nutritional intervention in the form of beneficial bacteria might heal dogs of anxiety, depression and other cognitive disorders is extremely appealing. Probiotics are widely available and generally considered to be safe for dogs, and hence could be considered low hanging fruit in terms of their use.
At a veterinary nutrition conference in April, researchers from the Nestlé Purina Institute presented their findings on the behavioural and emotional changes that dogs experienced following the administration of Bifidobacterium longum, a probiotic that has already been shown to reduce behavioural symptoms of anxiety in rats and humans.
Twenty-four anxious labradors were included in the crossover design, placebo-controlled study. For the first six weeks, all dogs were fed a balanced maintenance diet, but 12 dogs were also supplemented with a proprietary strain of B. longum, with the remaining 12 dogs being given a placebo. From weeks seven to nine, all of the dogs were given a washout period, where they received neither the placebo nor the probiotic. Then, for the next six weeks, dogs that had initially received the placebo were given probiotics, and dogs that had previously received probiotics were given a placebo. The dogs were monitored for physiological and behavioural changes throughout the 15-week trial.
The results indicated that dogs receiving the probiotic showed a reduction in behaviours that indicated that they were anxious. Various physiological measures of stress also decreased.
The general day-to-day behaviour of the probiotic-treated dogs seemed vastly improved, with 22 (90 per cent) of dogs appearing to be less anxious overall. Specifically, the incidence of barking, jumping, spinning and pacing were significantly reduced in the treated dogs.
Salivary measures of the stress hormone cortisol were also lower in 20 dogs (83 per cent) of dogs when receiving the probiotic, as measured during a formal test for anxiety. Heart rate variability was also improved in 20 dogs (83 per cent), and average heart rates were lower in 18 of the treated dogs (75 per cent), also suggesting a more positive physiological and emotional response to stressors.
Along a similar line of inquiry, a 2012 study published in the International Journal of Applied Research in Veterinary Medicine, also found that a course of probiotic treatment in dogs before and during a stay in kennels also helped significantly reduce the incidence of stress diarrhea in those dogs, suggesting that probiotics may have prophylactic as well as treatment benefits that are worth considering.
While studies into the potential benefits of probiotics in dogs are few and far between, the results are so far positive and consistent with published findings from studies into humans and other species.
While it may still take many years before we have a good understanding of the full range of benefits and potential harms from this form of intervention, the risks of giving it a go are considered low. It is advisable however, that if an owner is going to invest in a probiotics trial with their own pet, that they discuss it with their veterinarian first.
Not only do veterinarians know which are the best, quality-tested probiotics for your dog (the class action lawsuit against Danone in 2009 is a reminder that buying probiotics off the supermarket shelves will not necessarily deliver the benefits that are promised) but veterinarians may also recommend that other diagnostics and therapies are tried first, depending on what they see as the underlying problem.
I find that a course of probiotics can be a useful adjunct to many behavioural therapy treatment plans, particularly in those cases where dogs have experienced gastrointestinal upset and received antibiotics as part of their treatment.