Cachexia and Ageing
Cachexia is not just simple weight loss, but rather a complex condition involving wasting of skeletal muscle associated anaemia, lipolysis, insulin resistance, and anorexia and sickness syndrome. A consensus definition was developed that will allow practitioners to better define the condition.
Cachexia by definition: ‘a complex metabolic syndrome associated with underlying illness and characterized by loss of muscle with or without the loss of fat mass. The prominent clinical feature of cachexia is weight loss in adults (excluding endocrine disorders). Anorexia, inflammation, insulin resistance and increased muscle protein breakdown are frequently associated with wasting disease. Wasting disease is distinct from starvation, age-related loss of muscle mass, primary depression, malabsorption and hyperthyroidism and is associated with increased morbidity”
The optimal BMI for older persons are between 25-30, as a number of studies have shown that weight loss in the older person is associated with a marked increase in mortality risk. Apart from a very detailed explanation of the biochemical basis and pathophysiology of cachexia, this article also features some of the controversies in cachexia. Are cytokines an essential component of cachexia? The conclusion to this controversy is that while pro-inflammatory cytokines are an important roleplayer in many aspects of cachexia, they are not the only cause of cachexia.
Is fat or muscle the key tissue in cachexia? The outcome of this conference concluded that both muscle and fat play a critical role in the survival of cachectic patients, and that the one is not more important than the other one as survival depends on both protein and fat.
And is nutrition therapy necessary for the person with cachexia? There is clear data to support the administration of essential amino acids to enhance protein synthesis, eicosapentanoic- and docosahexanoic acid , to reduce inflammation and maintaining vitamin D levels above 30ng/ml to maintain muscle function and decrease falls in cachectic patients. On the contrary the presense of pro-inflammatory cytokines inhibits the ability of nutrition support alone to improve outcome. However, nutrition support remain an integral part of the medical management of the cachectic patient and even though it is not the ‘magic bullet’ without it the patient will die of starvation.
Some of the new advances in the treatment of cachexia was also discussed with a number of pharmaceutical agents seemingly improving and/or reversing cachexia. Controversy remains on the use of drugs that increases food intake as the weight gain early on is predominantly fat and not lean body mass. Novel nutrition approaches has also been developed. It is known that endotoxins can be activated through bacterial translocation from the gastro intestinal tract, a recent study showed that prebiotics (oligofructosaccharide) can decrease some of the pro-inflammatory cytokines in older malnourished patients. Evidence are increasingly suggesting that aggressive nutrition support together with new drug modalities will enhance the quality of life of the cachectic patients.
The Journal of Nutrtion health and ageing Vol 13, Number 1
Cachechexia and ageing: an update based on the fourth international cachexia meeting. JA Morley; SD Anker; WJ Evans.
