Dairy products – lauded by some as a fat loss tool or essential for bone health, but considered akin to poison by others. What approach should you take? Here is a quick guide:
Allergies and intolerances
It is possible to have a reaction to milk protein, and/or to be intolerant to milk sugar (lactose). Lactose intolerance is due to an absence or reduced amount of the enzyme required to break down the sugar – in this situation it ferments in the intestine, causing gas build up, bloating, discomfort and diarrhoea. In some populations (e.g. East Asia), lactose intolerance is almost universal, as dairy products are not traditionally part of the diet. Rates of lactose intolerance are generally low in Northern Europe, but there is a wide variation within Europe, with an estimated 70% of Sicilians having some degree of lactose intolerance, for example. This means that whilst needing to avoid dairy may have become “fashionable”, depending on ethnic background, many people may indeed have some difficult processing lactose.
The best way to determine this is simply through trial and error. Some people are able to tolerate almost any amount of dairy foods. Others can tolerate cheeses (where most of the lactose is fermented out), but not cream or milk, or they may have a quantity threshold, above which eating dairy produces symptoms. In others, the ability to break down lactose may fluctuate – so on some occasions you may be able to enjoy ice cream, whereas on other occasions the same dose may have you dashing to the toilet, or feeling sub-optimal the next day. If this is the case be cautious, and avoid large intakes of dairy products around important events or when you want to look and feel your best.
Some studies have suggested that dairy products may improve fat loss – this is thought to be due to the high calcium content – and the Dukan Diet (see Reviews) includes daily dairy. However, whilst being generally low in sugar, dairy products have a larger impact on insulin than would be expected, and can therefore contribute to fat gain!
The fat loss effects may be also partially due to dairy products being quite satisfying – eating a yogurt may mean a person trying to lose fat is less likely to snack on sweets and crisps. If fat loss is your goal, it is unlikely that you will achieve it through consumption of large amounts of cream – but there is no reason to completely avoid occasional good quality dairy products if you can tolerate them and if you enjoy them. They can be useful when viewed as condiments – a little grated cheese or dollop of creme fraiche can add variety to meals and prevent boredom or the feeling of constantly restricting oneself.
Dairy for women
A 2007 study linked intake of low fat dairy products to anovulatory fertility – the effect was not thought to be due to differing levels of vitamin D, calcium or lactose. Conversely, high fat intake from dairy was thought to potentially decrease the risk of anovulatory infertility.
Dairy is promoted as being important for preventing osteoporosis due to its calcium content – but there is not a simple relationship between dairy or calcium intake and decreased risk of osteoporosis or osteoporotic fractures. There is often a variance in what is measured in studies – whether it is bone density or actual fracture, which means it can be difficult to make comparisons. There are a number of studies that report little or no effect of high dairy or calcium intake on the risk of osteoporotic fracture in postmenopausal women, as well as studies that suggest that vitamin D3 may be of great importance for bone health. Many other factors are implicated in bone health, however, including protein intake. Research suggests that rather than causing bone loss through acidification, high protein diets actually improve bone health (J Am Coll Nutr. 2005 Dec;24(6 Suppl):526S-36S.), and low protein intakes in the elderly may be a key factor in the development of osteoporosis.
Finally, there are conflicting results from studies regarding dairy intake and breast cancer. Some studies suggest decreased breast cancer risk amongst women who regularly eat dairy products (this may be due to vitamin D content), whereas others propose a link between the hormones and growth promoters in milk and breast cancer. Low dairy intake has been proposed as one reason for low breast cancer rates in Japan (although soy, green tea and mushrooms have also been suggested). Milk is intended as a growth stimulating food, and so the idea that substances within it can stimulate dysregulated growth of dividing cells is logical – add to this the fact that many cows are treated with hormones and antibiotics means that it may be wise for dairy consumption to be limited.
Dairy and mucus
People with asthma and hayfever, or those suffering from temporary respiratory problems such as colds or sinusitis often find relief through avoiding dairy. Dairy products are considered “mucogenic”, although no mechanism has been proposed for this.
What should you do?
There are enough reasons to avoid consuming large amounts of dairy – it may increase cancer risk, can cause fat gain, add to respiratory tract irritation and cause digestive disturbances. Its role in bone health is not as clear as we are led to believe – other foods may be more important.
If you find dairy products difficult to tolerate, it makes sense to avoid them. Do not be tempted to replace with soy – high intakes of soy products can adversely affect thyroid and other hormones. Experiment with oat milk, hemp milk and nut milks instead.
If you can tolerate dairy products to some degree, and enjoy them, consider them to be condiments, or see if you can easily go without them. Avoid large quantities of any dairy product. Using small amounts a few times per week in cooking, or as an occasional snack is a better idea. Choose the best quality products – straight from the organic farm is the best option, and choose full fat, whether fertility is an issue or not, as low fat dairy products are more processed and often have added sugar. Avoid commercial yogurts and other commercial products.