IMPORTANCE OF MILK IN DIET
Compiled, & shared by-DR. RAJESH KUMAR SINGH, (LIVESTOCK & POULTRY CONSULTANT), JAMSHEDPUR Post no 1407 Dt 20/09//2019
JHARKHAND,INDIA 9431309542, rajeshsinghvet@gmail.com
Milk has been part of the human diet for millennia and is valued as a natural and traditional food. Milk and dairy foods are considered to be one of the main food groups important in a healthy balanced diet, and as such feature in the majority of national food-based dietary guidelines from the British Eatwell and Australian plate model , to the Chinese Pagoda and the Japanese Spinning top , the US pyramid , the Guatemalan pot and many others. As milk provides a substantial amount of vitamins and minerals in relation to its energy content, it is considered a nutrient dense food . Cows‟ milk provides a wide range of essential nutrients to the diet. Whilst milk as a source of calcium is often recognized, it is perhaps less commonly known that milk and milk products are also an important source of good quality protein, the B vitamins, B2 (riboflavin) and B12, and the minerals iodine, potassium and phosphorus . Milk consumption has been called a marker for an overall healthy diet because of its association with increased nutrient intake . There is some data to show that nutrient intake is enhanced when dietary patterns include milk and dairy products. For example, in an 18 month randomised controlled trial, British girls in the intervention group were asked to drink extra milk, whilst the control group maintained their usual diet. Consuming an approximate additional glass (186ml) of milk every day significantly increased intakes of protein, calcium, phosphorus, magnesium, zinc and riboflavin, whilst milk consumption and nutrient intake were unchanged in the control group . In a US study of milk drinkers, both flavoured and plain, intakes of vitamin A, calcium, phosphorus, magnesium, potassium were significantly higher than non milk drinkers. Indeed the Dietary Guidelines for Americans advisory committee report determined that without milk products, 19-50 year old women would reach only 44% of calcium recommendations, 57% of magnesium recommendations and 57% of potassium recommendations . For all age groups in the UK, milk and dairy are major contributors to calcium, riboflavin (vitamin B2), phosphorus and iodine intake in the diet.
Nutrients in Milk
Vitamins and minerals
B Vitamins
Milk is a good source of the B vitamins, riboflavin or B2 and B12.
Significant amounts of riboflavin are present in milk . Riboflavin is necessary for the release of energy from foods and the health of the body‟s membranes including the skin. It is also crucial for the maintenance of normal vision, normal red blood cells and functioning of the immune system. Riboflavin further contributes to the protection of DNA, proteins and lipids from oxidative damage. Milk and milk products are the main sources of riboflavin in pre-school children‟s diets and the diets of school children and adolescents (4-18 years), adults (19-64 years), and the elderly (65 years and over) . A 200ml glass of semi-skimmed milk provides 45% of an adult‟s (19-50 years) daily requirement for riboflavin . Vitamin B12 is required for the maintenance of healthy nerves and red blood cells, as well as normal energy production and cell division. It is also needed for normal function of the immune system, neurological and psychological function, and reduction of tiredness and fatigue . Milk products are the main sources of B12 in the diets of pre-school children diets, children and adolescents (4-18 years) and adults (19-64 years) . A 200ml glass of semi-skimmed milk will provide both a 6-year-old child and adult with their entire vitamin B12 daily requirement .
Calcium
Milk is an excellent source of calcium8 which, as commonly recognized, is essential for the healthy growth and maintenance of teeth and bones. Calcium is also important for normal blood coagulation, normal energy yielding metabolism, normal muscle and nerve function, normal digestive function and normal regulation of cell division and differentiation . Milk and milk products are the main sources of calcium in pre-school school children and adolescents (4- 18 years), adults (19-64 years) and the elderly (65 years and over) . A 200ml glass of semi-skimmed milk can provide a 6-year-old child with over half (55%) of his or her calcium requirement and can provide an adult (19-64 years) with over a third (35%) of his or her daily calcium requirement
Iodine
Milk is also a good source of the mineral iodine8 . Iodine is required for the production of the thyroid hormones and normal thyroid function, for normal energy yielding metabolism and contributes to the maintenance of normal skin . The main sources of iodine in the UK diet come from milk and dairy products in all age groups from preschool children to the elderly. A glass (200ml) of semi-skimmed milk will provide a child of 6 years with 96% of their daily requirement for iodine and an adult (19-50 years) with 44%, but there is some seasonal variation in the iodine content of milk .
Phosphorus
plays a vital role in the maintenance of healthy bones and teeth, as well as cell membrane structure and regulation of the body’s rate of energy metabolism. The main sources of phosphorus in the UK diet come from milk and milk products throughout all age groups. A 200ml glass of semi skimmed milk will provide a child of 6 years with 55% of their daily requirement for phosphorus and an adult (19-50 years) with 36% .
Potassium
Potassium is important for helping to maintain normal blood pressure and helps maintain muscular and neurological function . Milk and milk products are the main sources of potassium in the UK diets of pre-school children and the elderly (65 years and over), and the second largest contributor, after potatoes, in the diets of school children and adolescents (4-18 years) . A 200ml glass of semi skimmed milk will provide a child of 6 years with 29% of their daily requirement for potassium and an adult (19-50 years) with 9%
Macronutrients
Protein
Milk is a good source of high quality protein . Milk and milk products are the largest source of protein in pre-school children and the second largest contributor further to meat and meat products in all other age groups . Cows‟ milk contains about 3.5% protein by weight, and of this total protein, 80% is casein and 20% whey. Casein is the dominant protein in milk and can be fractionated into four major components: alpha, beta, gamma and kappa-casein. Whey protein is composed predominantly of beta-lactoglobulin and alphalactalbumin, but other whey proteins include serum albumin, immunoglobulins (IgA, IgG, IgM), protease peptones, lactoferrin and transferrin30 .
Carbohydrate
The principal carbohydrate found in milk is lactose. Cow‟s milk contains about 4.5g lactose per 100g milk and there is some evidence that lactose is the least cariogenic of the common dietary sugars. In addition, various other components of milk have been considered to be protective against dental caries .
Fat
The fat content of milk varies depending on whether milk is whole, semi-skimmed or skimmed. Despite a misconception that milk is „fattening‟, even whole milk contains only around 3.5% fat (3.5g/100g). Semiskimmed milk contains 1.7% fat (1.6g/100g or 1.7g/100ml). Skimmed milk contains only 0.1% fat (0.1g/100g or 0.1g/100ml). Since January 2008 1% milk, which as the name implies contains 1% fat, is now available on the market . Milk fat contributes unique characteristics to the appearance, texture, flavour and satiability of dairy foods. Dairy fat is a source of energy, essential fatty acids, fat-soluble vitamins, and several other components, such as conjugated linoleic acid (CLA) and sphingolipids30 . About a quarter of the fat in milk is monounsaturated . The remainder is mostly saturated fat, although some polyunsaturated fats and other minor fatty acids are also present. Palmitic, stearic and myristic acids are the major saturated fats found in milk . Dairy fat is also comparatively rich in the short and medium chain saturated fats. Research continues to unravel the complexities associated with individual fatty acids and fats from different sources and it is becoming increasingly apparent that not all fatty acids, or saturated fatty acids, have the same biological effects. There are a variety of saturated fatty acids in milk and many of these have no effect on plasma cholesterol. Conclusion Milk is a naturally nutrient rich and affordable product, with a high nutrient to energy ratio. Milk and dairy products are an important food group in many national dietary guidelines and may play a role in dietary quality. Whilst conclusive cause and effect relationship between milk and dairy intake and chronic disease has not been established, there is little evidence of any harmful effect and indeed some studies suggest milk and dairy products in the context of a healthy balanced diet may have some health benefit.
Milk and its products are one of the most important foods of the human being after domesticated animals since it is a unique and complete food for the early stages of the life of the newborn of mammals. Milk is a complete food in macronutrients, and yogurt also. Cheese, from the food side, is a first-rate alternative to meat, one of which is rich in proteins of high biological value. It is important to be part of our diet, which should be varied. Nutrient nutrients, which provide high biological value proteins and trace elements in easily absorbable forms, can benefit both nutritionally vulnerable individuals (children, the elderly, the patient) and healthy individuals.
What milk and its products offer us.
Proteins.
Foods of animal origin are an important source of proteins of high biological value (index greater than 90% and digestibility greater than 95%). They contain all the essential amino acids and are rich in the amino acid histidine, which is particularly useful in the body of young people. In addition, serum proteins promote bone formation and inhibit bone degradation. There are also a number of bioactive peptides derived from the proteins and formed during the fermentation of milk by microbes, during cheese maturation or during digestion. These peptides-based studies have anti-microbial activity and regulatory role in inflammatory responses (Immunoglobulins, Lactoferrin), prevent the development of inflammatory bowel disease (EGF growth factors, TGF-b), have antihypertensive activity (PP & VPP peptides in fermented milk) have a regulatory role in appetite by reducing food consumption (Casoxin) and enhancing calcium absorption (caseinophosphopeptides).
Fat.
They are also good sources of fatty acids. Milk fat is an important source of energy for fast-growing young people, is easily absorbable and has a high energy content (~ 9kcal per gram). In addition, it contains several essential fatty acids with important role in the body such as palmitoleic and oleic acid, linoneliko acid (reduces total and LDL cholesterol), arachidonic acid is a precursor of eicosanoids (prostaglandins, thromboxanes, leukotrienes), alpha-linolenic acid (reduces cardiovascular risk by multiple mechanisms), and long-chain polyunsaturated fatty acids EPA, DPA & DHA which reduce the risk of sudden death by multiple mechanisms and have beneficial effects in nerve system, development, and health. Finally, in milk and dairy products, there are unique fatty acids such as CLA, which has anti-cancer properties and reduces body fat in growing organisms.
Carbohydrates.
As far as carbohydrates are concerned, their variety of milk and its products are limited. The only sugar found in a considerable amount of milk is lactose disaccharide. The latter plays an important role (in combination with vitamin D) in the absorption of calcium from the intestine. In addition, it is an important structural element of the brain, it helps the metabolism of magnesium and, finally, the production of lactic acid during the breakdown of lactose by acid bacterial bacteria, contributes to the good functioning of the intestine, creating an unfavorable environment for the development of pathogenic bacteria
Vitamins and trace elements.
Milk and dairy products remain one of the main sources of calcium, magnesium, selenium, riboflavin (B2), vitamin B12 and pantothenic acid (B5) in human diets around the world, and are also good sources of zinc vitamins A, C, D, and B6 depending on the origin of the milk. In addition, the bioavailability of some nutrients such as calcium is higher than that of other foods.
What we have to look out for.
Allergies.
Allergy in milk usually occurs in infants and infants, so their introduction into the infant’s diet should be planned and gradual. At older ages, allergic reactions may be milder and each person should know what products they can consume. Allergies are due to the sensitization of the organism to certain milk albums, especially α-lactalbumin and β-lactoglobulin. However, it should be noted that allergic effects also appear after consumption of milk that may contain antibiotic residues. In this case, the allergy is due to the presence of antibiotics and not to milk proteins.
Poor absorption-lactose intolerance.
This is a pathological condition due to the reduced activity of the enzyme lactase in the small intestine. Thus, lactose remains undisturbed, accumulates in the intestine in large quantities, increases osmotic pressure and water concentration and leads to the induction of colic and diarrhea. It is the most widespread disorder associated with milk consumption.
Galactose-galactosemia intolerance.
It is a hereditary metabolic disorder that is not very common and occurs in 3 forms, two of which cause disease. The former is due to the lack of the enzyme galactokinase. The infant can not digest galactose and is rapidly led to cataracts and blindness if it is not immediately perceived and is not on a lactose-free diet from the first few days after birth. The second form is classical galactosemia, which is due to the existence of an enzyme that is necessary for the incorporation of galactose into the glycolysis cycle. This leads to the accumulation of galactose in the cells in the form of galactose phosphate. This causes damage to the liver and central nervous system, cirrhosis, cataracts, delayed growth and irreversible mental retardation.
How much we should consume.
Many countries have developed nutritional recommendations or guidelines based on the availability of local food, the cost, the nutritional status of the population, consumption and eating habits. Because of these various factors, the recommendations vary, but most recommendations suggest at least one portion of dairy products every day, with some countries recommending up to three servings per day. In Greece, the recommendation is two servings per day. However, it is of particular importance to choose the dairy product.
Milk.
A glass of milk (250 ml) can be consumed daily by all people over 24 months of age if they do not have any form of allergy or intolerance. Toddlers do not recommend daily consumption, especially if they are replacing breast milk, mainly because of possible allergic reactions but also because of their low iron content.
Milk and heart health
Cow’s milk is a source of potassium, which can enhance vasodilation and reduce blood pressure.
Increasing potassium intake and decreasing sodium can reduce the risk of cardiovascular disease, according to a study led by Dr. Mark Houston, director of the Hypertension Institute at St. Thomas Hospital in Tennessee.
The study showed that those who consumed 4069 mg of potassium per day had a 49 percent lower risk of death from ischemic heart disease compared with those who consumed around 1000 mg per day.
According to the National Health and Nutrition Examination Survey, fewer than 2 percent of US adults meet the daily 4700 mg recommendation.
Potassium-rich foods include cow’s milk, oranges, tomatoes, lima beans, spinach, bananas, prunes, and yogurt. A dramatic increase in potassium intake can have risks however, including heart problems, so any changes in diet or use of supplements must be discussed first with a physician.
Cow’s milk also contains a high amount of saturated fat and cholesterol, which have been linked to an increased risk of heart disease.
Milk and cancer
Vitamin D might play a role in cell growth regulation and cancer protection. Research shows that there is a higher risk of dying from colorectal cancer in geographic locations that receive the least amount of sunlight. Milk, too, contains vitamin D that can offer similar protection.
The National Cancer Institute (NCI) states that “Research results overall support a relationship between higher intakes of calcium and reduced risks of colorectal cancer.” They note, however, that the results of studies have not always been consistent.”2
The NCI also points to some studies that suggest an increased intake of calcium and lactose from dairy products may help to prevent ovarian cancer.
Milk and depression
Adequate vitamin D levels support the production of serotonin, a hormone associated with mood, appetite, and sleep. Vitamin D deficiency has been associated with depression, chronic fatigue, and PMS. Cow’s milk and other foods are often fortified with vitamin D.
Milk and muscle building
Cow’s milk is designed to help baby cows grow fast, so it makes sense that humans who drink cow’s milk can also bulk up quickly. Cow’s milk is a rich source of high-quality protein, containing all of the essential amino acids. Whole milk is also a rich source of energy in the form of saturated fat, which can prevent muscle mass being used for energy.
Maintaining a healthy amount of muscle is important for supporting metabolism and contributing to weight loss and weight maintenance. Sufficient dietary protein is needed to preserve or increase lean muscle mass. Dairy protein can support muscle growth and repair.
Cow’s milk does not seem to significantly help with weight loss. One analysis of studies found that increased consumption of cow’s milk in the short-term and without calorie restriction had no benefit for weight loss, with only modest benefits seen in long-term studies with energy restriction.
Low-fat milk can provide the benefits of milk while supplying less fat.
Milk and osteoarthritis
Osteoarthritis of the knee currently has no cure, but researchers say drinking milk every day has been linked to reduced progression of the disease. Their research was published in the American College of Rheumatology Journal Arthritis Care & Research.
