[Milk and health]

Milk has been an important part of Norwegian nutrition for generations. The article is a review of literature concerning research on milk and health.Relevant literature with results that were confirmed by others were chosen from acknowledged journals from Pubmed in the period 1977-2006, by using the search words milk, fat, atherosclerosis, omega-3, omega-6, cancer, allergy, trace elements, iodine and selenium.Milk and milk products contain many essential nutrients. The content of oleic acid, conjugated linoleic acid, omega-3 fatty acids, short- and medium chain fatty acids, vitamins, minerals and bioactive compounds may promote positive health effects. Certain studies indicate that a moderate intake of milk fat reduces the risk of cardiovascular disease, possibly through reduced formation of small dense LDL-particles, despite of its inherent tendency to increase total cholesterol. For individuals with genetic metabolic defects, milk proteins, fat and milk sugar may cause health problems. The low pH in fermented milk and the formation of substances during the fermentation process may have a beneficial effect. Full-fat milk and fermented milk lead to delayed gastric emptying, and thereby to reduced glycaemia and reduced appetite. Harmful substances may be formed when proteins react with sugar, especially at a high temperature; a fact that should be considered with an increasing use of sweetened milk products. The cow's diet affects the milk's content of many nutrients as for example fatty acids, iodine and selenium. The composition of milk for commercial use should be investigated.