Dairy is possibly my favourite food group. Milk, yoghurt and cheese make regular appearances in my day, and between my porridge and yoghurt obsession alone, I generally reach the recommended target of 2.5 daily serves without even trying.
Dairy is a rich source of calcium, accounting for around 60% of that mineral in the average Australians’ diet. Calcium, as you probably know, is essential for strong bones and teeth, as well as playing a role in nerve and muscle function.
Around 2% of our body is made of calcium, with the majority residing in the skeleton. During childhood and adolescence, it plays a key role in developing and strengthening bones until Peak Bone Mass is reached in the early twenties; thereafter, it remains vital in maintaining bone density. When the body is not taking in enough calcium, these functions suffer – this in turn can potentially lead to grim consequences, such as the degenerative disease osteoporosis (literally, ‘porous bones’).
So why dairy?
While it’s true that dairy is not the sole source of calcium available to us, it is the richest source of the mineral, and is more efficiently absorbed than others of plant or animal origin. Here are a few common sources:
|FOOD SOURCE OF CALCIUM||CALCIUM LEVEL PER 100G|
|Fish with bones||200mg|
And why not dairy?
But while dairy may have much to recommend it, not everyone is in agreement over the much-loved food group. Among the many reasons for this disinclination to dairy include:
It’s high in fat, and therefore can cause high cholesterol and cardiovascular disease:
It’s true that dairy products are naturally high in saturated fats, but with a wide range of reduced-fat products available there is no reason that cholesterol or cardiovascular disease should result from their consumption. Current recommendations are that reduced-fat varieties of milk, yoghurt and cheese should be consumed by those over 2 years of age. Evidence has actually shown that in fact dairy consumption may protect against cardiovascular ailments: a cross-sectional study of over 500 adolescents from 8 European cities discovered that, of all food groups, dairy was the highest predictor of a decreased cardiovascular disease risk.
It’s linked to cancer
There is some suggestion that dairy consumption is linked to both breast and prostate cancer, but not so much as to worry the experts. The Cancer Council Australia states that although dairy has been linked to both protective and harmful effects, the overall health benefits outweigh any potential risks.
It is the cause of allergies and mucus:
An ‘allergy’ to dairy products – or more precisely, lactose intolerance – is a condition in which an individual lacks the enzyme (lactase) responsible for digesting the milk sugars in dairy products. Largely determined by genetics, lactose intolerance is particularly common in those of Asian, Middle Eastern and African descent, and manifests itself through diarrhoea, abdominal pain and swelling (bloating). Such unpleasant symptoms are mainly brought on by the fermentation of lactose in the intestines by bacteria, due to the absence of lactase, and anything undigested is sent along the digestive tract.
But those with lactose intolerance needn’t steer clear entirely of dairy, as lactose free options are available (such as Liddel’s and Paul’s Zymil). Besides, contrary to popular belief, small amounts of dairy are usually tolerated – particularly yoghurt and cheese, which are lower in lactose than milk.
Then there’s the mucus myth, the idea that consuming dairy (particularly milk) can cause an increased production of mucus in the body. Feelings of oral or nasal discomfort have no scientific basis in relation to dairy, but allergy specialist Dr Ray Mullins suggests the sensation may be felt due to the viscous consistency of milk.
The calcium-osteoporosis link in negligible
This is a difficult one. On the one hand, there is decades of strong evidence showing that calcium – in the form of dairy – is correlated with positive bone health. On the other hand, dairy’s detractors will point to the contradictory results of The Nurses’ Health Study, which followed over 70,000 women over 12 years and concluded that increased consumption of milk actually resulted in more osteoporotic fractures.
But before you jump to conclusions and clear your fridge of dairy for good, it’s worthwhile remembering that osteoporosis is a multi-factorial condition – and that calcium consumption, while vital, is still only one aspect. Regular weight bearing exercise, adequate consumption of Vitamin D (which aids in the absorption of calcium) through both sunshine and the diet – these are also important considerations. Furthermore, the consumption of calcium early on in life – and the attainment of peak bone mass – will set the baseline for an individual’s risk of the disease.
Those who reject the calcium-osteoporosis link will also point to the low rates of osteoporosis in countries such as China and Japan, whose people traditionally consume little dairy compared to Australia, USA and the UK. Again, this doesn’t hold up to scrutiny. The International Osteoporotic Foundation points out that disease is greatly undiagnosed and undertreated in Asia, particularly in rural areas, and that the rates may therefore be much higher than documented. Indeed, as people of Asian descent are more susceptible to lactose intolerance, they are particularly at risk of calcium deficiency.
Milk is highly processed, and therefore bad for our health
Most milk sold in Australia undergoes two main processes before it reaches our supermarkets shelves: pasteurisation and homogenisation.
Pasteurisation is required by law, and describes the process in which milk is heated to 72 degrees Celsius for 15 seconds, then immediately cooled to 4 degrees or less. This process destroys harmful bacteria and ensures milk is safe for consumption, as well as extending its shelf life.
Homogenisation has made the iconic layer of cream at the top of the milk bottle a thing of the past, as milk is passed through a sieve-like instrument at high pressure to create uniform fat globules and a consistent texture.
These are the two processes all conventional milks undergo, and their purpose is to produce milk of a high quality, both in terms of health and sensory properties. Neither poses a risk to our health.
The use of hormones in milk production is prohibited and antibiotic use is highly regulated, with routine checks made to ensure that no milk for human consumption contains antibiotics from a treated cow.
Finally, genetic modification (GM) has very little involvement in the dairy industry, aside from the production of certain cheeses using a bacteria-derived enzyme (chymosin) as a processing aid. This is used as an alternative to the traditional chymosin, derived from animal sources, in order to make the product appropriate for vegetarian consumption.
How much should we be eating?
But what’s the recommended target, and what even is a serving size?
According to the newly revised Australian Dietary Guidelines, men and women aged between 19 and 50 years are encouraged to consume 2 ½ serves of dairy or alternatives a day.
|1 cup (250ml) milk|
|2 slices (40g) hard cheese, such as cheddar|
|½ cup ricotta cheese|
|¾ cup (200g) yoghurt|
The case against dairy is pretty weak, so with all those myths cleared up, there’s no excuse to be skimping on the ever-important food group!
Categories: fact or fiction