Studies in humans and rats indicate that selected nutraceuticals can assist in reducing the presence of neuro-chemicals associated with stress. As a result of this, manufacturers propose that diets enhanced with such nutraceuticals can support the management of behavioural responses associated with stress. A number of studies have suggested that the addition of a range of such nutraceuticals to the diet of animals can assist in altering and managing their behaviour. Punica granatum from the pomegranate has been used to treat insomnia and anxiety in rats. The roots and rhizomes of Valeriana officinalis (the common valerian plant) have been used to treat mild sleep disorders and ‘nervousness’ in mice and extracts for the rosemary bush (Rosmarinus officinalis) have been found to have antianxiety activities in a species of mouse. L-Theanine from green tea leaves has been widely reported to reduce stress and to reduce the heart rate during chronic anxiety in humans and many studies suggest that a lack of l-tryptophan is associated with anxiety and depression. In addition, studies on a range of species have linked a lack of omega-3 with mood and behavioural disorders, and the presence of free radicals to long-term harm to organ systems, including the brain. However, none of these nutrition-based studies have been performed on dogs.
The range of veterinary nutraceutical products to aid anxiety-related behaviour change in dogs is considerable, but the support for their use has been based on studies on individual ingredients in other species or on case studies. Peer-reviewed research has been absent from the sales armoury. But the Veterinary Record has recently published a randomised controlled clinical evaluation of a nutraceutical enhanced canine diet: Effects in dogs with behavioural disorders of a commercial nutraceutical diet on stress and neuroendocrine disorders (Sechi et al http://veterinaryrecord.bmj.com/content/early/2016/11/24/vr.103865.full).
The study from the University of Sassari (Italy) Veterinary Department, took 69, approximately 3-year-old dogs of mixed breeds and assigned them randomly to a control diet or to the nutraceutical diet, over a period of 45 days. Both diets fulfilled The European Pet Food Industry's nutritional requirements and were approximately identical in nutritional composition regarding protein, oil/fat, fibre, moisture, vitamin, mineral and energy content. In addition, the nutraceutical diet contained Punica granatum, Valeriana officinalis, Rosmarinus officinalis, Tilia (lime) species extracts, Crataegus oxyacantha (from the Hawthorn), l-Theanine and l-Tryptophan.
Blood samples from each dog were analysed both pre-diet administration and after 45 days of the diet. After the 45 day trial, serotonin (associated with a feeling of wellbeing in humans), dopamine (which drives reward motivated behaviour) and beta-endorphins (with natural analgesic properties) were found to be significantly increased in the dogs that had received the nutraceutical diet in comparison to the normal diet. In addition, the dogs fed the nutraceutical enhanced diet had reduced levels of the neurochemicals noradrenalin and cortisol, that would normally be associated with stress.
This is the first randomised, controlled evaluation assessing the use of nutraceuticals and neuroendocrine blood parameters in dogs with behavioural disorders and its authors consider that it demonstrates the significant positive effects, obtained within a short 45-day period, of feeding a diet enhanced with a combination of hydrolysed fish proteins, rice carbohydrates, P. granatum, V. officinalis, R. officinalis, Tilia species, C. oxyacantha, green tea extract and L-tryptophan and omega-3/6.
Now all we have to do is to work out which manufacturer is producing the diet that was studied and, of course, which of the array of ingredients were actually responsible for the observed endocrine changes! So, despite this very interesting study, the veterinary profession need to ensure that while supporting their patient's needs through nutraceutical use, a patient's recovery from distress and depleted emotional welfare is not being left to chance by limiting support to dietary changes.