N-3 fatty acids, cancer and cachexia: a systematic review of the literature.

Use of n-3 fatty acids (FA) has been reported to be beneficial for cancer patients. We performed a systematic review of the literature in order to issue recommendations on the clinical use of n-3 FA in the cancer setting. A systematic search was performed in MEDLINE, EMBASE, Cochrane and Healthstar databases. We selected clinical trials or prospective observational studies including patients with cancer and life expectancy >2 months, in which enteral supplements with n-3 FA were administered. Parameters evaluated individually were clinical (nutritional status, tolerance, survival and hospital stays), biochemical (inflammatory mediators), and functional (functional status, appetite and quality of life (QoL)). Seventeen studies met the inclusion criteria; eight were of high quality. The panel of experts established the following evidence: (1) oral supplements with n-3 FA benefit patients with advanced cancer and weight loss, and are indicated in tumours of the upper digestive tract and pancreas; (2) the advantages observed were: increased weight and appetite, improved QoL, and reduced post-surgical morbidity; (3) there is no defined pattern for combining different n-3 FA, and it is recommended to administer > 1.5 g/day; and (4) better tolerance is obtained administering low-fat formulas for a period of at least 8 weeks. All the evidences were grade B but for 'length of treatment' and 'advantage of survival' it was grade C. Our findings suggest that administration of n-3 FA (EPA and DHA) in doses of at least 1.5 g/day for a prolonged period of time to patients with advanced cancer is associated with an improvement in clinical, biological and QoL parameters.

Nutrición, fibrosis quística y aparato digestivo

The prevalence of hyponutrition in cystic fibrosis is high although it may vary according to the different studies. Detection of hyponutrition should be done by combining different methods, depending on their availability. However, the simplest and most validated criterion is to measure at each visit the weight (and height in children) in order to calculate the body mass index and categorizing hyponutrition according to absolute criteria: in adults < 18.5 kg/m(2), and in children as percentiles of the body mass index. Worsening of the nutritional status is directly related with the decrease in lung function parameters and it has been proposed as a morbidity (and even mortality) predictive factor in people with cystic fibrosis, independently of the level of pulmonary dysfunction. Exocrine pancreatic insufficiency is present is approximately 70-90% of the patients with cystic fibrosis and the genotype-phenotype correlation is high. Most of the patients with exocrine pancreatic insufficiency tolerate a high-fat diet provided that they are treated with pancreatic enzymes at appropriate doses. The prevalence of diabetes increases with age, reaching up 40% of the cases in patients older than 30 years. Clinical liver involvement is less prevalent (it approximately affects 1/3 of the patients). Other intestinal complications such as meconial ileus, gastroesophageal reflux, obstruction of the distal intestine, or fibrosing colon disease may also condition malnourishment. In patients with cystic fibrosis, a usual high-fat diet providing 120%-150% of the recommended calories is advised. If the nutritional goals are not achieved or maintained with diet modifications, artificial supplements may be added, although the recommendation for their use has not been endorsed by solid scientific evidences. The most frequently used preparations usually are polymeric or hypercaloric. The indications for enteral (through a tube, especially gastrostomy) or parenteral nutritional support are similar to those used in other pathologies. Dietary and nutritional control should be included in a multidisciplinary program allowing the improvement of the functional capacity and the quality of life and reducing, at least from a theoretical viewpoint, the morbimortality associated to malnourishment in these patients.