Milk and milk product consumption in India was a dietary essential for over 8000 years. It is well documented in many of the ancient literature. Milk was also strongly recommended to be consumed daily according to Ayurveda.
Milk and dairy products are an excellent source of good quality protein with all essential amino acids, high digestibility thus having the highest PDCAAS value of 100. Protein is a critical component of growth and development particularly in children and adolescents and sustains good health in adults including the elderly. Infants until six months of age are to be exclusively fed on human milk and animal milk is recommended only after one year of the child. Human milk is further advised to be continued till the child is 2 years.
Protein in milk helps in satiety and may be an aid to weight loss. A glass of milk was considered as a quick, healthy and sustaining food for children who were in a hurry. Milk and dairy are also known to improve lean body mass (Abargouei et al Int J Obes, 2012). There is an inverse association between total dairy and Yoghurt intake and risk of Diabetes Mellitus. There may be multiple mechanisms including the effect of fermented milk products on gut microbiome or the effect of branched chain amino acids on Insulin and glucose metabolism. (Frid AH et al Am J Clin Nutr, 2005). A diet high in milk and dairy reduces risk of childhood obesity and improves body composition in adults provided it has no added sugars (Thorning et al ,Food Nutr Res, 2016). Moderate milk and dairy intakes of 200-300ml / day may not increase risk of cardiovascular disease. Even whole milk is considered unrelated to CVD.
Bone health in childhood and adolescence is better in those who consumed milk and dairy. However, for adults the overall incidence does not support high dairy consumption for reduction of fractures. These were based on US data (Willet et al , NEJM, 2020).
There have been some reports on milk intake and cancer risk but neither Prostate Cancer, Bladder, Pancreas or Lung have been conclusively linked. On the contrary there could be a reduced risk of colorectal and breast cancer in women (Thorning et al 2016). Plant based milk equivalent and milk comparisons may not be valid since they are nutritionally entirely different. There are also no long-term comparative studies on several health risks.
Data on total mortality from 29 cohort studies showed that milk and dairy consumption were not associated with increased overall mortality (Astrup et al Eur J Epid, 2017). Studies comparing protein sources and mortality showed plant proteins were associated with lower mortality than milk and dairy, but milk and dairy had less mortality than eggs and processed meat but was comparable with poultry, fish and unprocessed red meat. (Willet et al NEJM, 2020). One should not apply this data to India where despite high production the per capita consumption of milk is still low. Even these authors recommend that in low-income countries dairy foods can improve nutrition. The present recommendations do not emphasize on use of low-fat milk but recommends to avoid any kind of sugar sweetened milk or dairy products. This is applicable in our country due to the rapidly increasing incidence and prevalence of overweight/ abdominal obesity and the consequent Diabetes.
There may be a proportion of the population who may genetically have primary lactase deficiency that leads to clinical Lactose intolerance. Even these individuals can tolerate low lactose milk or fermented milk products. In India a study showed lactose intolerance be as high as 66% in Southern India vs 27% in the north (Tandon et al Am J Clin Nutr 1981) . A study by Gallego Romero (Romero et al ,Mol Biol Evolution, 2011)quoted by Rob Mitchum from Univ of Chicago (uchicagomedicine.org) found that the mutation in lactase gene among Indians was similar to the one in Europeans, linking the gene to migration. The article stated that only 18% of Indian population digest milk. However, the clinically identifiable symptoms are not so frequent possibly due to a greater GI tolerance in our population or the lesser volume of milk consumed or due to higher fermented milk product intake.
Milk protein allergy is another issue seen in 1.5% to 3% of infants and falls to < 1% by 6 years of age (Gupta RK et al IAP treatment guidelines committee 2022) There are studies to show that even in those children the allergy may resolve with time. They may be the severe IgE mediated or the milder Non IgE mediated.
Another matter of concern is the morbidity associated with A1 type of cow’s milk protein. Fortunately, all our Indian breed of cows as well as buffalos yield only A2 milk (NDRI).
Overall, the benefits of milk significantly outweigh the risks seen in some individuals. These risks are also identifiable and manageable.