Nutritional criteria of milk and their benefits on health
8 July 2016
Milk is an essential aliment throughout life. Its nutritional quality comes from its peculiar composition:
- Lactose: most impostant component of milk dry matter. Milk owes its smooth and slightly sweet taste to lactose, a glucid which acts as a fuel especially for brain and muscles. Lactose also has an additional nutritional advantage: it improves dairy calcium utilisation by the body, by increasing its intestinal absorption and the assimilation of dairy proteins.
- Lipids: lipids play an energetic role. Milk fat features:
- Saturated fatty acids: they have interesting characteristics. Short chain saturated fatty acids are particularly well digested and are rapidly used as an energy source by the body. Others with long chain play a role in children nervous system development.
- Unsaturated fatty acids: they are composed of mono-unsaturated fatty acids, that are known not to impact cardiovascular system, and of poly-unsaturated fatty acids. Milk contains few unsaturated fatty acids but its contribution to essential fat intake must not be neglected (linoleic acids and a-linolenic acids help maintaining membrane structures).
- Proteins: Milk proteins are numerous and have high nutritional values, milk is a vital aliment thanks to these proteins. Our body uses indeed proteins to maintain a healthy state. Every day, throughout its life, the body destroys and renews part of the proteins especially during growth, pregnancy, nursing and old age in order to create new tissue.
- Minerals: milk contains most of the minerals essential to the body, the most important are:
- Calcium: 2 g.l-1 : Calcium circulates in the blood and helps renewing all body cells, throughout life. It fulfils many functions for vital organs and plays an important role to maintain bones.
- Phosphorus: 0.9 g.l-1
- Potassium: 1.5 g.l-1
- Magnesium: 0.13 g.l-1
- Vitamins: milk is a natural source of vitamins from the B-group:
- B1-vitamin or thiamine, essential to proper running of nervous and muscular systems and to blood sugar metabolism (glucids).
- B2-vitamin or riboflavin, essential to renew and maintain tissue. It is also indispensable to transform food into energy. It plays a role in vision and encourages growth.
- B9-vitamin or folic acid, helps creation of red globuls and of nervous cells. It also prevents certain forms of anemia (iron deficiency).
- B12-vitamin or cobalamin, helps creation of nervous cells.
- Milk also provides fat-solubles vitamins:
- A-vitamine or retinol: is active in transmitting light to the retina, it plays a role in protecting skin and mucous membranes and encourages growth.
- D-vitamin or calciferol: is the anti-rickets vitamin. It helps calcium and phosphorus metabolism.
Various kinds of milk exist
Varioius kinds of milk are defined by two main criteria (fat content and heat treatment):
- Whole milk: more than 3.5% fat by liter
- Semi-skimmed milk: 1.5 to 1.8% fat by liter
- Skimmed milk: less than 0.5% fat by liter
- Milk with peculiar fat percentage: fat content must be clearly indicated.
- Raw milk: milk undergoes no treatment except for refrigeration after milking.
- Microfiltered fresh milk: milk is treated by microfiltration (filtration by a porous membrane to retain microbial flora of skimmed milk without modifying physicochemical composition).
- Pasteurised milk: milk is heated at 72°C for at least 15 seconds before being cooled at less than 6°C
- Sterilised milk: milk is heated at 115°C for 15 to 20 minutes before being cooled.
- UHT-sterilised milk: Ultra-High-Temperature sterilisation, milk is heated at 140°C for 2 seconds.
Other criteria may influence milk classification:
- Nutrient enrichment (vitamins, proteins, minerals…),
- Lactose content modification,
- Organic farming,
- Condensed milk (sweetened or not),
- Dry milk (milk powder),
- Infant milk that comes from complex recipes in order to meet specific needs of infants and young children.
Click here to discover the numerous types of milk offered by FIT.