Lactose intolerance
RETHINKING COWS’ MILK: IS IT REALLY GOOD FOR US?
Dr Justine Butler, Senior Researcher and Writer
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This article looks at the history of milk consumption, evolution and lactose intolerance. The links between dairy and a range of other illnesses are examined along with the role cows’ milk in bone health. Milk is frequently referred to as a fundamental component of a healthy diet. Why is this? Is milk the only source of some essential nutrient, or is milk unique in that it contains all the nutrients that we require? No other animal on the planet continues to drink milk beyond weaning and, not just that, drinking milk taken from another species that is often pregnant. This unusual practise has become a concern for some scientists. The origins of dairy farming
Dr Justine Butler is a Senior Researcher and Writer at Viva!Health. Justine holds a PhD in Molecular Biology, BSc Biochemistry and Diploma in Nutrition. She has published an extensive list of reports, guides and factsheets for Viva!Health and written many articles for health journals, regional and national press.
Sheep, cattle and goats were domesticated in parts of the Middle East and central Asia over 9,000 years ago, but it is thought that the use of animals for milk was not practiced until between 6,000 to 8,000 years ago in Asia Minor or Turkey (1). Although this sounds like a long time ago, in evolutionary terms it is very recent history. Hominid (modern human) fossils date back to nearly seven million years ago. If this is represented as a 12-hour clock, starting at midday, humans would have started dairy farming less than one minute before midnight! Dairy farming today
Like humans, cows don’t produce milk unless they have recently given birth. However, the modern dairy cow is routinely impregnated whilst she is still producing milk (this ensures that the
milk yield is kept high). At least twothirds of cows’ milk in the UK is taken from pregnant cows (2). This inevitably affects the levels of hormones found in milk. There are 35 hormones and 11 growth factors in milk (3). Some scientists are particularly concerned about the oestrogen content of cows’ milk (4), suggesting that cows’ milk is one of the important routes of human exposure to oestrogens. Milk production is big business, estimated to be worth £3.8 billion in the UK (5). Although the numbers of dairy cows in the UK have fallen year by year, the milk yield has continued to rise. Over the last 10 years, selective breeding and high protein feed has increased the yield per cow from just under 18 litres per day to over 20 litres per day. The increase in milk yield far offsets the fall in the number of dairy cattle (6). There is a clear trend; fewer cows are being forced to produce more milk, what the cost is to human health remains to be seen. What lies beneath…?
The composition of mammalian milk reflects the requirements of the species producing it, be it buffalo, badger, dog or rat - the best milk for them is that of their own species. While whole cows’ milk contains four percent fat, milk from the grey seal contains over 50 percent fat because seals need a lot of body fat to survive in cold water (7). Whole cows’ NHDmag.com February 2015 - Issue 101
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