Milk is supposed to be a complete food providing almost all nutrients needed by the body and the very fact that a new born baby depends entirely on its mother's milk for growth and development is a standing testimony to the wholesomeness of milk. Of course mother's milk differs from cow's milk in some aspects but still latter is one of the most balanced and nutritive products known to man. If this is so why do we see in the super markets processed milk products like mineralized milk, Vitamin C milk, milk fortified with several vitamins and minerals, calcium fortified milk, omega-3 milk, milk fortified with vitamins A and D, etc vying for the attention of the consumers? Obviously the answer is "business"!
Pasteurized milk products containing added vitamins A and D are the most frequently encountered on the market shelves and addition of calcium and/or omega-3 fatty acid is a later development. A fortified food by definition refers to food with addition of essential nutrients to levels higher than those normally found in that food. In the case of milk, it is deficient only with regard to iron, copper, manganese and vitamin C and there may be some justification if their levels are brought up to make it a complete food. But for an adult why should milk contain all the essential nutrients? After all it is only a supplementary food and forms part of a diet containing cereals, pulses, oil seeds, meat, fish, poultry, fruits and vegetables and spices which can provide the deficient nutrients. In order to get omega-3 acids equivalent to that present in 50 gm of salmon, one will have to gulp at least 2 liters of milk! A recent survey in the US brought out the ground reality that paying a higher price for a branded fortified milk product does not bring any additional benefit to the consumer as compared to generic milk.
Partly technology has to be blamed for enabling the industry to incorporate such difficult nutrients like iron, ascorbic acid, omega-3 acids. vitamin A and D into an aqueous emulsion like milk which is sensitive to pH changes affecting the protein stability. While addition of vitamins A and D to skimmed milk is understandable, full fat milk contains adequate quantities to serve as a supplementary food. Scientifically vitamin D fortification is acceptable because of the role it has in increasing absorption of calcium and phosphorus by the body, though vitamin D is synthesized in vivo from the precursors through exposure to sun light. Efforts to add iron were aimed at delivering this critical nutrient to rural masses, most of them being anemic due to poverty conditions, as a part of government intervention programs. Nestle, one of the dairy giants with global presence developed products like Nido, Ninho. Nespray, Klim, Bear brand and ideal which are milk powder preparations fortified with iron, zinc, vitamin A and some other micro nutrients for African population but how far these products are affordable to those who need them is a matter of conjecture.