Dairy products are, from a conventional nutritional perspective, very much a ‘double-edged sword.’ On the one hand, we are told, they provide the body with valuable calcium for healthy bones. On the other, they can be rich in ‘artery-clogging’ saturated fat and cholesterol. The answer, we are assured, it to consume dairy products in low-fat form. Skim/skimmed milk and low-fat yoghurts and cheese are now the order of the day.

Yet, our appetite for such products is based on extremely wonky evidence. For a start, the amount of calcium derived from dairy products appears to have little bearing on bone health (including in women and children). Also, the idea that eating saturated fat or cholesterol causes heart disease is not supported by the evidence either.

Over the last few years we’ve seen plenty of evidence come to light which fails to link saturated fat with an increased risk of heart disease. More importantly, though, is the mountain of evidence we have that shows that moving from saturated fat to ‘healthier’ polyunsaturated fats (including ‘vegetable’ oils) does not confer health benefits.

Recent times have seen at least some shift in thinking away from saturated fat and cholesterol as a cause of heart disease towards something altogether different – inflammation. Inflammation is what causes an ingrowing toenail to be red, hot and painful. However, low-grade inflammation throughout the body may have no obvious symptoms, but is implicated in heart disease, as well as other chronic diseases including obesity and type 2 diabetes.

Some may therefore argue that the impact a food has on health has little (if anything) to do with its impact on cholesterol levels in the bloodstream, say, and much more to do with its propensity to promote inflammation. We might want to emphasise anti-inflammatory foods (such as so-called omega-3 fats found in fish such as mackerel, herring, sardine, trout and salmon) and avoid over-consumption of ‘pro-inflammatory’ foods.

Previous work has linked the consumption of dairy products with higher levels of markers of inflammation in the body. However, such studies (so-called ‘epidemiological’ studies) only tell us that two things are associated with each other, not that one thing is causing the other. To know if dairy products actually cause inflammation we need to give people these foods and see what happens to levels of inflammation in the body.

This week saw the publication of a study where researchers gathered together relevant studies in this area [1]. Eight studies were found. In four of these, dairy products had a favourable effect on markers of inflammation. In the other four, they appear to make no difference.

Overall, therefore, this review provides evidence that dairy products are not particularly pro-inflammatory. However, that does not necessarily mean they should be eaten with gay abandon.

One of the problems I see quite frequently in practice is ‘food sensitivity’ – unwanted reactions to food that can cause diverse issues including digestive problems, asthma, eczema, joint pain, headaches and fatigue. I have to say, I do find dairy products are frequent offenders.

As a general rule, though, I do find raw (unpasteurised) dairy products appear to be better tolerated than pasteurised, and I also find in practice that yoghurt is better tolerated than milk. This probably has to do with the fact that the bacteria deployed in the fermentation process that forms yoghurt partially digest milk proteins, making them easier to digest and less problematic. I also find butter to be generally very well tolerated, perhaps on account of the fact that it has relatively little protein in it and no lactose (another potential problem) to speak of. If milk and cheese is to be consumed, I find goat’s and sheep’s products to be generally better tolerated than cow’s.

References:

1. Labonté ME, et al. Impact of dairy products on biomarkers of inflammation: a systematic review of randomized controlled nutritional intervention studies in overweight and obese adults. Am J Clin Nutr epub 28 Feb 2013