Milk is produced by mammals in order to feed their new born to grow. Such milk is the only diet available to the young mammals till such time they gather fodder to feed themselves and grow on their own.
The history of milk consumption
However from time immemorial humans have started to domesticate certain animals for their milk primarily and for meat, beef etc. Cows, Buffaloes, goats and sheep are the top four mammals which humans rear for their milk. Although you can consume milk from camels, reindeer, yak, horses and donkeys as well, they are both difficult to procure and unpleasant to drink and hence are less common. Milk from various brands is now a substitute or supplementary food in addition to manufacturing various food products for preservation and consumption at the appropriate time.
World milk production
The total milk production by the world population is above seven trillion tons. As per the year 2011 data, the per capita milk consumption by various countries ranges from 9.1 liters by China,39.5 liters by India and 135.6 liters by Ireland with many other countries falling anywhere in between. Most of the countries are now self-sufficient in production of milk. The last country to attain self-sufficiency in milk production is China.
Whenever breast milk is insufficient in providing the required energy to human new born babies, cow or buffaloes milk is the substitute food. These days however, doctors recommend formula milk. But the fact is that humans have been consuming milk ever after becoming adults, although this was not an ancient practice.
Benefits of milk for adults
Research studies establish the benefits of consumption of milk by adults. Similarly there are research studies which contradict, or rather reject the benefit theory and pronounce that consumption of milk by adults do more harm than good.
Calcium and Potassium
The first and most important benefit of milk is that it provides good amount of calcium and potassium which are essential for human health. Calcium is to maintain the mineral density of the bones. Calcium is indispensable to protect the body from arthritis, osteoporosis, pre-menstrual syndrome and obesity. Since milk is a readily and easily available affordable source of food containing high amount of calcium, it is good for people of all ages.
Brain cells functioning
For effective functioning of brain cells in adults a powerful antioxidant called glutathione is required, which is available in milk. Being a natural source of good quality protein milk helps in muscle building and maintenance of body weight.
Maintaining bone density
When milk is fortified with vitamin D, it is more helpful in maintaining the bone density. The other important nutrient in milk is potassium which maintains the blood pressure by which heart related diseases are prevented. Low fat milk is preferred to vegetable to get the required amount of potassium. For the required quantity of potassium large quantities of vegetables have to be consumed whereas three glasses of milk is sufficient.
Dietary research on milk consumption shows that milk provides the easiest and fastest way of obtaining the recommended daily amount of calcium of 1000mg, which is required to maintain the bone health.
What is lactose intolerance?
Lactose intolerant people cannot take milk because they lack the necessary enzymes to break the sugar in milk and are not able to digest the milk, causing flatulence or diarrhea.
The problems due to consuming milk
Some are found to be allergic to milk and the allergic antibody created by the immune system may lead to vomiting or wheezing.
The other types of milk allergies are asthma, eczema, bleeding, pneumonia and migraines. Milk is an acidifying animal protein. Casein, a protein found in milk is found to be difficult to digest by a large number of people. The symptoms of casein or lactose intolerance are similar. It has to be identified only with a blood test.
Impact of drinking milk on the kidneys
Consumption of higher quantities of milk leads to high level of potassium intake which is detrimental to the health of the kidneys. If the potassium is not removed by the kidneys and excreted through urine, the kidneys may be damaged. The high calcium intake increases the risk of prostate cancer.
Is milk really good for the bones? – The other theory
In one of the studies it was found that, ironically, if the calcium in the milk especially in pasteurized milk is not absorbed by the body, it reduces the calcium already available in the bones thereby weakening the bones. The calcium loss in the bones is due to the acidifying effect of the milk which tend to neutralize the calcium intake and the reserve too.
Consumption of milk and other dairy products, particularly at the age of 20, is associated with an increased risk of hip fracture in old age (American journal of epidemiology). Some studies establish that osteoporosis rate is higher in countries where consumption of milk is high, (or where consumption of calcium is high).
Milk procured from cattle that are unconventionally raised contain more beneficial fatty acids as they freely roam in fields and consume grass or other organic food. In other words the benefit derived from the milk is proportional to the healthy food intake by the cattle.
In the early years of 20th century only raw milk was consumed. But now the milk is pasteurized and processed, on account of which the milk becomes more acidifying and weakens the bones. However unsweetened and fermented dairy products like yogurt and cream are acid neutral and can be consumed.
In some places in order to increase the yields from the milk animal antibiotics and a genetically engineered growth hormone are injected which has harmful effect of causing breast cancer.
Should one consume milk or dairy products at all depends on the circumstances and other food availability or habits. For example taking a glass of milk with breakfast may give sufficient protein required for people who do not consume eggs, beans or meat. People who are lactose intolerant must look to other sources that provide enough calcium.
There is no reason to conclude that milk is detrimental to adults but the over consumption of milk is. The solution is to go in for non-dairy nutrient foods as alternate sources of calcium, protein and potassium and make up the shortfall with milk or dairy products.
It is desirable to consume raw milk compared to pasteurized or processed milk. Even while consuming raw milk it may be ensured that the cattle is not administered with antibiotics to increase milk yield.
With more than 7 trillion tons of milk produced and a majority of human population world over already consuming milk, there is no alarming reason to stop consumption forthwith. But one need to be judiciously selecting the milk or dairy products and prudentially restricting the quantity of intake to stay healthy.