Milk is white colored liquid produced only by mammals to feed their young ones. Mammals produce milk through mammary glands. Milk is the primary source of food for newborns. Milk contains all essential nutrients which are required for the growth. Milk plays a major role in the diet. It is a great source of vitamins and minerals. Its composition includes major elements which are needed for body growth and healthy body. It helps the body to be saved from various health issues.
Milk composition varies from species to species. The cow’s milk is used for drinking mostly. Its primary constituents are
- Carbohydrates – Milk contains approximately 4.9 % of carbohydrates. The lactose is the main carbohydrate which is present with a micro amount of monosaccharides and oligosaccharides. Lactose is a disaccharide of galactose and glucose.
- Fat – Milk contains approximately 3.4% of total fat. Fats present in milk contains most complex fatty acids. Milk fat has over 400 fatty acids. Out of 400 only 15 to 20 fatty acids make 90% of milk fat. Milk fat contains 65% saturated, 30% monounsaturated and 5% polyunsaturated fatty acids. Milk with reduced fat has 2% of milk fat, low fat has 1% and skim milk has 0.5% of milk fat.
- Proteins – Milk contains 3.3% proteins. A human requires 9 amino acids for body growth and these are all present in milk. All milk proteins are synthesized in mammary glands, but 60% of amino acids used to build proteins which are obtained from cow’s milk. There are 2 major proteins present in milk one is casein, and other is serum or whey protein. Casein proteins contain phosphorus and will coagulate at pH 4.6. The serum or whey protein does not contain phosphorus and remains as a solution in milk at pH 4.6. In cow’s milk, approximately 82% protein is casein whereas 18% protein is present as serum.
- Vitamins – Milk is a rich source of vitamins. They play a major role in body functions such as metabolism, oxygen transport. Vitamins help the body to utilize carbohydrates, proteins and fat. Milk contains water soluble vitamins thiamin, riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid ( vitamin B5), pyridoxine (vitamin B6), cobalamin ( vitamin B12), vitamin C and folate. Milk is an excellent source of thiamin, riboflavin and vitamin B12 whereas niacin, pantothenic acid, vitamin B6 present in trace amount. Milk also contains fat soluble vitamins A, D, E and K.
- Minerals – Minerals play an important function such as enzyme function, bone formation, water balance maintenance and oxygen transport. Minerals like magnesium, selenium, phosphorus, calcium, potassium, and zinc are present in good amount. Many minerals in milk are associated together in the form of a salt such as calcium phosphate. In milk, 67% calcium, 35% magnesium and 44% of phosphate are bound with casein micelle and remaining are soluble in serum. Milk contains a trace amount of copper, iron, magnesium, and sodium is not considered as a major source of minerals in the diet.
- Enzymes – These are proteins which perform biological functions. There are many enzymes present in milk. Milk enzymes come from various sources, the native milk and airborne bacterial contamination and bacteria which is added externally for fermentation. Lipase is enzymes that degrade fats, and one of the major lipases in milk is lipoprotein lipase. Proteases are the enzymes that degrade proteins. The major source of protease is plasmin. It is important for cheese manufacturing. Alkaline phosphatase is a heat sensitive enzyme in milk that is used as an indicator for pasteurization. Lactoperoxidase is most heat stable enzyme found in milk and when it combined with hydrogen peroxidase and thiocyanate has antibacterial properties.
There are all 9 essential nutrient elements are present in milk. These nutrients make milk very healthy drink for the body.
- Calcium – required for healthy teeth and bone
- Protein – source of energy that builds and repair muscles tissue
- Potassium – helps to keep healthy blood pressure
- Phosphorus – strengthen bone and generate energy
- Vitamin – contribute to maintaining bones
- Vitamin B12 – promote healthy red blood cells and nerve tissue
- Vitamin A – maintain healthy eye sight, skin and immune system
- Riboflavin (Vitamin B 12) – convert food into energy
- Niacin ( Vitamin B3) – metabolize sugar and fatty acids
There are milk types based on the presence of fat content
- Whole Milk – It contains 3.25% milk fat by weight. 150 calories are present in 8 ounces of whole milk with 8 grams of fat.
- 2% Milk – This milk is labeled as 2% milk which means the milk fat is 2% total weight of milk. A glass of 2% milk ( 8 ounces) contains 5 grams of fat and contain all 9 essential nutrients like whole milk.
- Low-fat Milk – An 8 ounce serving of low-fat milk contains 2.5 grams of fat and 100 calories as compared to whole milk which has 150 calories in the same amount.
- Skim milk or Fat-Free Milk – This milk contains low milk fat about 0.5% of milk fat by weight but has all essential nutrients. 8 ounces of milk contains 80 calories.
- Organic Milk – Organic dairy farms produce organic milk. Cows there raised without the use of pesticides, synthetic fertilizers, antibiotic and hormones. These cows produce high-quality organic milk.
- Lactose-free Milk – it is also real cow’s milk, but the natural sugar in milk lactose is broken down. It still contains all nutrients like protein, calcium and vitamin D. This milk is good for people who are lactose intolerant.
- Raw Milk – This milk does not undergo pasteurization. It does not contain any vitamin and protein since they are all destroyed by heat. This milk cause health hazards and is not widely available.
Milk Health Benefits
Milk provides various health benefits which include bone strength, prevention of illnesses such as hypertension, smoother skin, stronger immune system, dehydration, respiratory problems, dental decay, obesity and some forms of cancers.
- Rehydration – Water makes almost 90% of body mass and balances the fluids in our body. Fluids are an integral part of our body and required for every single process to be done. Therefore they need to be frequently replenished. Milk contains a good amount of water molecule and is considered as best fluid for rehydration apart from water.
- Muscle Strength – Milk is a rich source of vitamins, fats, and proteins. Milk is a rich source of energy in the form of saturated fats which can prevent muscle mass to be used as energy. Healthy muscle mass is essential for healthy metabolism. Drinking milk can enhance muscle strength during exercise. A glass of milk gives the body what it needs to recover after exercise. It helps to maintain soreness while replenishing fluids which are lost during the workout.
- Healthy Bone and Teeth – Milk is an excellent source of calcium and essential minerals to maintain healthy bones and teeth. Milk maintain healthy bones and helps to resist tooth decay and cavities.
- Charming Skin – Milk contains all essential elements which are good for skin. It contains lactic acid which acts as exfoliator and enzymes to keep the smooth skin. Milk also contains antioxidants which used to prevent skin damage caused by environmental toxins. Amino acids present in milk help to keep skin moisturized.
- Healthy Heart – Milk has potassium which can promote vasodilation and reduce blood pressure. Consuming high potassium and low sodium decrease the risk of cardiovascular diseases.
- Prevent Cancer – Vitamin D present in milk can promote cell growth regulation and cancer protection. Cancer is an uncontrolled growth of cells. So milk may also help to prevent cancer.
- Healthy Body – The numerous properties of milk helps to lower high blood pressure and risk of stroke. It resists the cholesterol production by the liver, and it can also act as an antacid. Vitamin A and B can enhance healthy eyesight and immune system.