Aneela Hameed, Raheel Suleman & Saeed Akhtar
Milk has truly been considered as nature's single most complete food and we can never deny the significance of milk because it contributes essential nutrients in considerable amounts than any other single food. If we consider milk as a food, it fulfills the requirements in broad prospectus: (a) growth, (b) reproduction, (c) supply of energy, (d) maintenance and repair and (e) appetite satisfaction. The need of these groups can vary person to person, and in some cases not all the stated functions of the food need to be served, e.g. adults no longer require food for growth whereas infants do.
As a nutritional point of view, the functions of a food are served particularly through the different vital components, consisting of carbohydrates, proteins, lipids, minerals, vitamins and water. Milk is a wonderful source of calcium and phosphorus for the growth of bones and teeth, and it also contains riboflavin, vitamins B6, A, B1 and B12 (antipernicious anaemia vitamin) in considerable amounts.
Proper nourishment plays an imperative role for achieving physique and fitness objectives. When the body is physically pushed, the demand for protein can considerably increases; this increased demand can make it unwieldy to meet protein needs. From studies, it has been confirmed that milk proteins have importance over vegetable proteins in terms of promoting muscle hypertrophy after hectic trainings. Animal milk proteins have ability to promote muscle protein synthesis to some extent through activation of the mammalian target of rapamycin pathway and they are considered as complete proteins.
Milk proteins are important components of milk; they play significant role in many functions in human body and are of great therapeutic value as well. When we consume a protein source, our body utilized the 20 amino acids (key components of “protein”) to repair our bones, muscles, organs and almost every body part and tissue in the human body. Milk proteins are outstanding sources of essential amino acids (i.e. amino acids that must be obtained in the diet because the body cannot make them using other amino acids), and easy to digest. It is a complete protein that contains all 20 amino acids and all nine essential amino acids (phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine).
Milk proteins have been classified into casein (phosphorus-containing proteins) consisting of about 76-80% of the total milk proteins, which is considered significant as technological point of view and the serum proteins, comprising roughly 20-24%, has valued as Immune power. Serum proteins and whey proteins are generally similar but technically difference is that, whey protein containing k casein fractions found in whey a byproduct separated with k casein fractions during cheese manufacturing and has unique nutritional status. Serum proteins are naturally a mixture of beta-lactoglobulin (~65%), alpha-lactalbumin (~25%), bovine serum albumin (~8%) and immunoglobulins.
A mammary epithelial cell of animal udders is a place where milk components are synthesized and large quantities of blood flow through the udder. One liter of milk is obtained, when 800-900 L blood moves around the myoepithelial cells. Major milk proteins, caseins, α-lactalbumin and ß-lactoglobulin are synthesized in myoepithelial cells of mammary glands and are only produced by this, whereas milk immunoglobulin and serum albumin are absorbed from the blood. Moreover a limited amount of immunoglobulin is synthesized by lymphocytes which exist in the mammary tissue (called plasma cells).
Milk Serum proteins may have anti-inflammatory or anti-cancer properties. If we talk about human health then potential effects of these proteins are of great interest and are currently being explored as a way of reducing disease risk, as well as a possible additional treatment for several diseases. According to recent researches, it serves as a functional food in controlling the conditions such as hepatitis B, cancer, cardiovascular disease, HIV, osteoporosis and even chronic stress.
Research on whey protein concentrate is opening up a new window for researchers by discovering relationship among cancerous cells, glutathione (GSH) and whey protein. High concentrations of sulphur-containing amino acids (cysteine and methionine) in whey proteins are leading to enhance immune function through intracellular conversion to glutathione1. The role of glutathione is as antioxidant that protects the body against some toxins and free radical damage. Animal studies have proved anticancer potential of whey proteins, believed to derive mainly from the antioxidant, detoxifying and immune enhancing effects of Glutathione. And lactoferrin has also preventive effects on hepatitis C and B viruses. In vitro study results have also been showing inhibition of growth of cancer cells in human breast after treating with the Protein Bovine serum albumin (BSA).
Whey can be used for Nutritional Therapy by health professions with purpose as gastrointestinal supporters. Whey protein is quickly digested; make it ideal to help in refueling recovering muscles immediately before and after work. It is not recommended for consumption during rest time when body normally goes without food for hours. During sleeping hours, protein in slow digestion is more favorable to muscle repair and re-growth and casein may serve this purpose as it is slow absorbing protein that takes 3-4 hours to reach peak levels in blood amino acids and protein synthesis, and 7 hours to become fully absorbed. Casein also makes body feel less full than whey and it offers a great, between-meal protein snack.
Serum proteins takes less time for absorption but not fully digested and some of the intact proteins particularly ß-lactoglobulin may stimulate a localized intestinal or a systemic immune response referred to as milk protein allergy.
It’s true, God has blessed humans with many gifts of nature and one of those gifts is “Milk.” After reviewing plethora of scientific studies it is concluded that properties naturally present in milk have made it a complete diet for everyone regardless of age and gender.
– Department of food science and technology, Bahauddin Zakariya University, Multan.