Vet360 Vol 03 Issue 03 June 2016 | Page 13

ONCOLOGY cer patients have a tolerance range for dietary intake of various nutrients e . g . lactate 1 , this homeostatic reservoir is narrower than for healthy patients .

Essentially , malignancy causes alterations in the major nutritional axes as follows :

• PROTEINS – patients have skeletal muscle loss due to increased activity of proteolytic ( catabolic ) pathways and processes , even though liver protein synthesis increases . This causes protein metabolism to be shifted toward the tumour ( s ), and not replacing the muscle loss ( sarcopenia ). The altered liver metabolism is typical of the “ acute phase protein response ” seen in many inflammatory diseases . οο

Clinical consequence – if protein intake does not match requirements , poor wound healing and immunity and altered GIT function result .

• FATS / LIPIDS – the cachexia seen with malignancy is also due to reduce fat synthesis with concurrent lipolysis , driven by various cytokines and chemicals . Insulin resistance caused by various cytokines and tumour-derived factors may be an important driver of this altered lipid state . 2 In addition , the finding that some tumour cells have only a limited ability to utilise fats for gluconeogenesis ( the generation of glucose from non-carbohydrate sources ) leads some to believe a higher fat diet is physiologically appropriate to cancer patients . In fact , dogs allowed to self-select foods according to the satisfaction of energy intake , will tend to select a diet that is 30 % protein , 63 % fat and only 7 % carbohydrate . 3 In addition , the type of fat eaten seems to be important , with diets higher than 5 % in ω3 fatty acids advised by veterinary nutritionists . 4 οο

Clinical consequence – patients with inadequate lipid intake may experience alterations in energy status , increased usage of muscle amino acids to drive gluconeogenesis ( further sarcopaenia ), altered lipid-soluble vitamin homeostasis ( Vit A , D , E and K ) and greater susceptibility to oxidative damage of other organs .

• CARBOHYDRATES – at the centre of many arguments about cancer metabolism are carbohydrates ( CHO ). In this respect we are not discussing fibre , which is discussed below . Carbohydrate is an energy source used by all cells , but less effectively in cancer , due to insulin resistance at the cell membrane . This is aggravated by a relative or absolute hyperlactataemia which may be worsened by administration of Ringer ’ s Lactated intravenous solutions 1 , 5 Malignancy sufferers express embryonic versions of certain enzymes and have

Protein , Fat & Carbohydrate Percentage Dry Matter Contents of Various Diets Recommended Values from Roudebush et al ( 2004 )

Issue 03 | JUNE 2016 | 13