The influence of nutrition on canine behaviour

The idea that the food that we eat can affect our emotional state, behaviour or even our medical health has been around for centuries. Most of us know of individuals who say that they experience adverse reactions to, for example, milk products, pork, citrus fruit, red wines, certain colouring agents and preservatives. The reactions people report include headaches, itching, diarrhoea, vomiting and amongst a few children some rather dramatic behavioural problems. This is a controversial area for clinical research in human medicine and psychiatry because of the highly individual nature of these food reactions. But Worsley and Crawford for instance, two Australian authors recently estimated that some 8 per cent of Australians were so affected. This was based on a random survey they did of 5,000 Australians, the question being ‘do foods, and if so which foods, adversely affect your behaviour’. This 8 per cent of the human food-consuming population can be a powerful lobby even though they only represent a minority of consumers. Parents of children who react to one of the commonly-used food additives, tartrazine, have led the food industry to reformulate their convenience foods, like chocolate and ice cream to be yellow, but without tartrazine, using biologically-based, rather than synthetic dyes. There has been no such specific or systematic interest in diet and canine behaviour. If it is a tricky area to work with in human nutrition, it must be a great deal more difficult with dogs. Humans can report on their fitness, well-being or illness, but dogs are mute. We really should be considering what is inside the stomach when considering how a dog is behaving. There is a tremendous amount of social interaction between the puppies and the dam in the first few days of life. A large proportion of the time the family unit is together is spent in consuming food and the main purpose of that food is simply to maintain metabolism and achieve growth. A number of psychologists and biologists have studied the effects of chronic and in some cases acute food deprivation upon the development of the mammalian brain and general behaviour. In the laboratory rat for instance, Rosenweig and Leiman in the ’60s showed that chronic food deprivation did affect the development of the Central Nervous System and in particular, at critical periods such as the stage when the long nerve fibres were being myelinated. Acute food deprivations at such a time, say day 10 in the rat