THE growing problem of pet obesity and what to do about it still appears to dominate much of the current nutrition-related research and scientific endeavour. The classical approach of decreasing caloric intake along with increasing energy expenditure still holds true, with the commercially available diets for weight loss mostly taking the approach of restricting fat and calories. It’s recognised that without subsequent modification of the diet, this can lead to hunger and subsequent begging. The strain this puts on the owner’s attitude towards the diet and the effect on compliance shouldn’t be underestimated. Hence, much of the nutritional research carried out by pet food companies has been aimed at finding ingredients which produce better satiety and reduce begging behaviour. Increasing dietary fibre to help with gut distension has been shown to cause stretch of satiety-related receptors, leading to a feeling of fullness. Further work has shown that increasing the levels of protein has an additional satiety-inducing effect through triggering the release of cholecystokinin as well as helping to preserve lean muscle mass. Gram for gram, protein produces a greater post-prandial thermogenic effect, with the result that fewer calories are subsequently available as excess to be laid down as fat. Recent studies show that combining these approaches and increasing fibre and protein together, have the most marked effect and lead to an improvement in weight loss in obese dogs.
Weight regain
Sadly, weight regain following weight loss is common and known to occur in about 50% of dogs. The reason for this isn’t clear at this time, though it’s postulated that following a return to an ideal, lean weight, the body’s maintenance energy requirement may be lower and therefore any ongoing dietary manipulation needs to take account of this lowered need. In a recent study, dogs fed a purposeformulated weight loss diet regained less
weight than those switched to a standard maintenance food.
As with ourselves, the initial hurdle of weight loss must be accompanied by continued monitoring and dietary adjustment or the hard work may have been in vain.
Hyperthyroidism in cats
Elsewhere in the world, attention has been focused on the feline, with several recently published abstracts showing that feeding a diet restricted in iodine levels resulted in normalisation of T4 levels in cats with hyperthyroidism. limiting the dietary iodine (to less than or equal to 0.32ppm) lowered the serum total thyroxine in a group of cats with naturally occurring hyperthyroidism and returned them to a euthyroid state. The serum total T4 concentrations decreased three weeks after feeding this low-iodine food, and remained within the T4 reference range with no adverse effects seen within the study period. Hill’s has launched Prescription Diet y/d feline Thyroid Health in the US, as the first commercial diet of this type to help manage hyperthyroidism. Crucially, the company recommends that no other food is fed whilst on this diet as additional iodine from treats, food scraps and other pet foods can lead to it becoming ineffective, hence compliance is very important.
MCTs for brain ageing
In dogs, another recently published article in the British Journal of Nutrition lends more weight to the argument for the role of food in cognitive decline in dogs. Previous studies showed that supplementing the diet with antioxidants and omega-3 fatty acids appeared to help manage the behaviourally manifested signs of brain ageing in dogs. This more recent study appeared to confirm that Medium Chain Triglycerides (MCT’s) could also impart benefits, with a group of older dogs whose diet was supplemented with MCTs showing better performance in cognitive based tasks. It’s thought that the ability of the brain to use glucose, its preferred energy source, decreases with age. Ketones can provide an alternative energy source; the increased level of ketones derived from the MCTs may help to boost the brain’s energy supply, leading to an improvement in cognitive performance.
Fifth vital assessment
Perhaps the biggest news in the last year in small animal nutrition has been the WSAVA’s initiative to recommend the inclusion of a nutritional assessment into the standard physical examination for every pet. The nutritional assessment guidelines, published earlier this year in the JSAP, come as a set of recommendations from the WSAVA Fifth Vital Assessment Group. They have adapted the American Animal Hospital Association’s guidelines into what they consider to be a globally
applicable, easy-to-use tool. Including the assessment in every pet consult helps to provide optimal patient care, and takes a proactive stance to ensuring adequate nutrition throughout the pet’s lifetime in health and disease. The guidelines recommend looking at the pet’s nutritional status by considering animal-specific factors, dietspecific factors and feeding management and environmental factors. A screening evaluation should be performed on all pets visiting the clinic, with an extended evaluation introduced where risk factors for disease are identified. BCS is a key part of the assessment, along with a muscle condition scoring system (MCS) which is currently under development, and validation. A more proactive approach to
nutritional assessment is already in daily use at the RVC’s Queen Mother Hospital. The Nutritional Support Service, headed by US nutrition diploma-holder Dan Chan, is a formalised clinical service which monitors and ensures adequate nutritional support of hospitalised patients, as well as providing nutritional consultations to other specialists at the referral centre and clinicians in private practice. A similar service has been set up at the Royal (Dick), headed by Dr Marge Chandler. It’s hoped that the recognition of the vital role of nutrition in pet healthcare by these institutions will trickle down and inspire practices to take a similarly proactive stance.
References
Diez, M. et al (2002) Weight loss in obese dogs: evaluation of a high protein, low-carbohydrate diet. J Nutr 132: 1,685S- 1,687S.
Weber, M. et al (2007) A high protein, high fiber diet designed for weight loss improves satiety in dogs. J Vet Intern Med 21: 1,203-1,208. German, A. J. et al (2010) A high protein high fibre diet improves weight loss in obese dogs. Vet J 183: 294-297. German, A. J. et al (2011) Long-term follow-up after weight management in obese dogs: the role of diet in preventing regain. The Veterinary Journal May. Melendez, L. M., Yamka, R. M., Forrester, S. D. et al (2011) Titration of dietary iodine for reducing serum thyroxine concentrations in newly diagnosed hyperthyroid cats [abstract], J Vet Intern Med 25: 683. Melendez, L. M., Yamka, R. M. and Burris, P. A. (2011) Titration of dietary iodine for maintaining serum thyroxine concentrations in hyperthyroid cats [abstract], J Vet Intern Med 25: 683. Yu, S., Wedekind, K. J., Burris, P. A. et al (2011) Controlled level of dietary iodine normalizes serum total thyroxine in cats with naturally occurring hyperthyroidism [abstract], J Vet Intern Med 25 :683-684. Pan, Y., Larson, B., Araujo, J. A. et al (2010) Dietary supplementation with mediumchain TAG has long-lasting cognitionenhancing effects in aged dogs. Brit J of Nutr; doi:10.1017/S0007114510000097, Published online by Cambridge University Press, 9th February.
