Shashya Diyapaththugama,Wayamba University Undergraduate, BSc in Food Science and Nutrition, Applied Nutrition Department,
Most of us start the day with a cup of milk. Some of us drink milk in the evening or at night which means many of us consume milk or milk tea twice a day. As Sri Lankans, we mostly consume powdered milk. According to data retrieved from the Census and Statistics Department, milk production (cow and buffalo) in 2018 stood at a staggering 471,592,800 litres. According to the data from FAO, Sri Lanka is currently 15-20% self-sufficient with milk products. Imports are estimated to account for some 80% of domestic consumption. However, in the present context, there are concerns as to whether milk consumption is healthy or not.
Nutritive value of milk
In Sri Lanka, we commonly speak of cow’s milk in terms of drinking. Milk provides carbohydrate, protein, fat, calcium, vitamins A and D and a small concentration of vitamins B and C.
Changes in nutritive value during processing
Milk is available in the market in either liquid or powdered form. The liquid form of milk is either pasteurised or sterilised. These are heat treatments during which the nutritive value of fresh milk alters. During pasteurisation, vitamins C, B1 and B12 are lost in certain percentages. During sterilisation, more of these vitamins are destroyed. Powdered milk is the most common form of milk available in Sri Lanka, but developed countries mainly consume liquid fresh milk. Spray drying is the common technique used to convert liquid milk into powdered milk. Mainly water is removed in this process. According to customer requirements, the milk fat content can be changed. Therefore, market contains full-cream, low-fat and non-fat milk products.
Is milk essential?
Milk is a rich source of calcium and protein. Protein is required in tissue growth and calcium for bone growth. To obtain calcium, milk is the most convenient source.
Infants up to six months should be fed only breast milk which contains necessary nutrients in correct proportions. After six months, the child should receive proper food for growth.
Calcium is needed for growing children for bone growth. As they grow taller, the length of bones must also increase. For a healthy bone to grow, these children must have adequate calcium in their diets. Bone growth does not occur throughout lifespan. A bone gradually grows as the child grows and bone mass reaches a peak by about 35 years. Later, bone mass begins to decline, which means bones start breaking down. If you did not have a well-grown bone by the age of peak bone mass, you are at the risk of getting osteoporosis at older ages. Osteoporosis is the condition in which your bone becomes porous due to lack of calcium deposition. Therefore, the age before you reach your peak bone mass is critical and you should consume adequate calcium to facilitate proper bone growth and to prevent from getting osteoporosis at older ages.
Issues associated with commercially-available milk powder
Every now and then, issues come into discussion with regard to milk powder which may or may not be proved to be true. Once there surfaced a rumour that milk powder was adulterated with melamine. Certain farmers add water to liquid milk to increase its volume. As a result of this dilution, milk has a lower protein concentration. Therefore, to increase the nitrogen content, melamine is one possible but illegal additive in milk. Melamine is an organic chemical used in plastics, adhesives, dishwashers and whiteboards. Its health effects on humans are not experimentally tested. It is believed to cause kidney stones and also cancer. Another issue that recently came into discussion was the addition of lard/pork fat into milk to increase milk fat. The original milk fat is said to be removed to make butter and, to compensate the loss, pork fat is said to be added. However, these issues are not proven and yet open for debate.
Substitutes for milk
In these circumstances, one may be unwilling to consume milk powder. In terms of nutritive value, fresh milk is the richest and safest, but as fresh milk spoils sooner, refrigerators are needed for storage. Comparatively high in cost, milk powder is most commonly used in Sri Lanka. Milk is the most convenient source of calcium for us. But there are other calcium rich food such as sprats, small fish with bones, salmon with bones, woodapple, green leaves and other calcium fortified food. Also, there are dairy options such as yoghurt, cheese, curd, paneer and condensed milk a person could consume subject to availability and affordability. For instance, one glass of milk made with three teaspoons of milk powder can be replaced with 80ml of yoghurt or three tablespoons of curd.
Disorders related to milk
Lactose intolerance is one common condition where some people lack lactase enzyme in their bodies to digest milk. As a result, they develop diarrhoea, vomiting, bloating and abdominal pain conditions. Although this is common in Europe, it is very rare in Sri Lanka. If you are lactose intolerant, you should avoid milk but consume fermented milk products such as yoghurt, curd and cheese. Some may have allergies to milk and should hence avoid it.
Does milk cause phlegm?
Some people habitually reduce the consumption of milk and dairy products when they catch a cold or cough. Some believe the body produces more phlegm/mucus due to milk. But research has proved that there is no such association between milk intake and symptoms of mucus production in healthy adults.
Is it a must to drink milk?
You must obtain adequate protein and calcium for proper growth and good health. Calcium must be taken adequately until you reach the age of about 35 years, where you reach your peak bone mass. Yet, some people have doubts whether milk powder is safe or not and for which there is no proven answer. Also, those who are keen on reducing their fat consumption can select low-fat and non-fat milk products. There is no hard and fast rule to drink milk as long as you select alternative sources to obtain adequate nutrients. Nevertheless, fresh milk can be theoretically listed as a convenient source of calcium. The quality and safety of milk powder are uncertain.