Is Your Dog's Diet Contributing to Behaviour Issues?

A diet that is high in protein can certainly affect behaviour in some dogs. Dogs on a commercial complete diet containing too much protein can suffer from anxiety, aggression, restlessness, light sleep and depression. Too much protein in the diet can also exacerbate existing mental health/nervous system issues such as post-traumatic stress disorder. This is due to a lack of serotonin in the brain which regulates mood. Serotonin production relies heavily on the amino acid tryptophan which is found in many ingredients such as fish, eggs and chicken. Unfortunately in an excessively high protein diet this essential amino acid – tryptophan- has to compete with other amino acids also found in proteins. Competing in this way can result in low levels of tryptophan and therefore difficulty producing serotonin and in turn cause instability of mood. Most dogs are quite happy on a high protein diet, but some dogs may have insufficient serotonin production as a baseline and it is these individuals that may benefit from the trial of a lower protein diet.

The average protein content of a middle of the road ‘one size fits all’ dog food marketed as a maintenance food for an adult dog usually contains around 25% protein. An adult dog’s average protein requirement for weight maintenance is around 18%, most working dogs require around 25% and a racing sled dog during work requires around 35%. So for a dog in a pet home the maintenance diets available would appear to be only suitable to the athletic working dog due to the elevated protein content, or are they? Unfortunately manufacturers of pet foods are geared towards profit, to this end the ingredients list can be very misleading. There are vast differences in the qualities of different protein sources with some generically termed proteins being difficult or impossible for the dog to metabolise. Any protein termed as ‘animal’ ‘meat’ or ‘poultry’ is generally speaking likely to be of a very low quality, look instead for specifics such as ‘chicken’ ‘beef’ or ‘lamb’. Although the vast proportion of complete pet foods available appear to have too high a protein content this is not always the whole truth and they could actually be of a very low ‘useful-protein’ value contrary to the company marketing insinuations. Careful analysis of the labelling of a food is required to make sense of the confusing terms, unfortunately a full breakdown of ingredients is often not available on the packaging – however details are usually available on the manufacturer’s website or upon request.

There are a vast myriad of complete foods to choose from but there appears to be a huge gap in the market as I have found to my irritation. Most foods that contain high quality, easy to absorb protein tend to be very expensive and excessively high in protein making them only entirely suited to very active dogs in full time work, whereas the cheaper lower protein foods available, although initially appear ideal, are virtually all made up of exclusively low grade protein meaning that the already low protein content is very much lower than initial analysis would suggest. The only way I have found to comfortably match the protein requirements of my particular pack has been to find a 23% chicken protein food and to keep the dog’s exercise on the vigorous end of the scale! In summer when this level of exercise is not really practical due to the dog’s thick double coats I reduce the protein content by reverting to the same brand’s ‘mature’ food which is almost identical in every respect but includes less calories and only 19% chicken protein, in this way I allow for the more sedate period without changing the composition of the food too much. This works for me but finding a solution entailed a lot of research in order to cut through the different terms and marketing jargon.

As tryptophan is found in abundance in poultry and eggs a good way to ensure that your dog is getting enough is to feed a chicken based food of suitable overall protein content rather than one based on red meat, or to supplement a standard food with egg white. Egg white is an excellent source of protein and contains over 40 different proteins including all 20 proteogenic amino acids required for protein synthesis. It is the best ‘dog suitable’ source of tryptophan and as it has a low calorific content is a good solution for adjusting the intake of tryptophan and other amino acids without the need to adjust the calorie intake/amount food, this is a way of introducing a good balance of amino acids without increasing the calorie intake/exercise requirements. There are also some excellent supplements available that maximise serotonin production.

B6 is required for the conversion of tryptophan and supports the nervous system. Other B vitamins are required for the efficient absorption of B6 so the addition of a B vitamin complex to the diet can help where dog continues to exhibit symptoms despite appropriate adjustments to protein content in the diet. In addition to this some disorders such as post-traumatic stress disorder can severely deplete levels of serotonin, put simply, due to the dogs elevated and frequent perceived need for a fight or flight response. In cases where dogs are experiencing anxiety to the level where the skin is dry and flaky (this can be a side effect of stress), a good alternative to/addition to albumen is oily fish such as sardines, these are good for replacing the oils in the coat and skin during periods of stress as well as being a good source of tryptophan, if sardines are tinned in oil and the oil is to be given too, the addition of sardines should be limited to once or twice a week to avoid digestive upsets.

It should be noted that very low protein diets may stunt growth in younger dogs and compromise the immune systems of all, a total of 22 essential amino acids are required for a healthy diet and reducing the protein content of the diet severely is not recommended, a diet with 18% being of a good quality protein is the ideal to trial if serotonin production is thought to be a factor, as a maintenance diet for an adult dog that is not in work.

Lowering protein in the diet is unlikely to eliminate aggressive or anxious behaviour entirely but in some cases will allow the dog to achieve the correct brain chemistry and enable a more successful outcome to any programme of behaviour modification.