Is dairy ACTUALLY bad for our gut?

This is important. There are a lot of #guthealth facts and fads floating around and this is one we really need to understand better because the depth of this is getting serious. One of the first things most people are told to do in the pursuit of #guthealth is cut dairy (and gluten - another topic another day) now this message isn’t just coming from influencers, this is coming from professionals and even gastroenterologists. The message is that dairy plays a role in poor gut health and that the elimination of dairy is beneficial in creating a healthy gut microbiome. So let’s go over the science and set some records straight.

There are a few things to cover before we delve into this topic. 

  1. I am not pro or anti diary. I do not get paid by dairy companies, I have no personal interest in whether people choose to consume or avoid dairy. I am pro-evidence, pro science. 

  2. We will not be covering environmental or ethical reasons why one might choose to avoid dairy in this article. That is another conversation for another time. 

  3. I am not discussing the ability or inability for some people to digest lactose in this article, that doesn’t appear to be the context in which this argument is made and if it was then lactose-free dairy would be a suitable equivalent. We can talk more about lactose intolerance in another article. 

Okay so let’s delve in then.. There are no studies, zero, zilch, nudda that show a negative effect of consumption of cows dairy on the human gut microbiome. In fact the research shows quite the contrary. Fermented dairy products have time and time again been shown to be beneficial for the gut microbiome. The live cultures found in these fermented dairy products have been shown mostly survive digestion and make their way live to the large intestine.

So where the hell is this notion that dairy is bad for the gut coming from? What is the reason for this false information being spread? When I tried to understand the claims it appears they fall back on the statement that high consumption of animal protein and saturated fats isn’t good for the microbiome. Now this is true. We do have science for this. A diet that helps achieve a diverse, thriving microbiome is one that is rich in fibre, predominantly plant based proteins, unsaturated fats and limiting animal protein and saturated fats. BUT what we do know is that you do not have to be vegan to have these benefits, so what that means is that having SMALL amounts of animal protein and saturated fats does not harm the gut microbiome, especially in the context of a fibre rich, plant based diet. Dairy is also not for many people a significant contributor to saturated fats. Full fat dairy milk is 5% saturated fat, coconut oil is 90%, macadamia nuts are 12% regular beef mince 11%  (not saying these are bad just showing that dairy is relatively low on the sat fat spectrum). 

There was one study in 2016 that was done in hamsters (definitely not humans) that showed when soy protein milk was compared with dairy protein consumption that there was a significant improvement in the diversity of the microbiota of those hamsters that had the soy and a negative effect on the gut microbiome in those fed the dairy protein. However, we can’t actually draw conclusions from this. In the study the soy or the dairy protein was the ONLY protein that these animals consumed. So it is like comparing an animal protein diet to a plant protein diet and we know a plant protein diet is better for the microbiota but that takes the whole dairy argument out of context. When humans consume dairy protein it isn’t their only source of protein. Also, hamsters are hamsters, not humans.


What does this mean for you?

It means moderate consumption of fermented dairy products like yoghurt, kefir and some cheeses may in fact be beneficial for the gut microbiome, especially when consumed in the context of a predominately plant based diet. It means that a diet high in animal protein is not optimal for our gut, but it does not mean that cutting out dairy is going to benefit your gut, especially if your dairy consumption is from fermented food sources.

Now I always welcome science-backed feedback so if by chance I have missed some high quality, evidence that dairy consumption in humans does negatively effect the microbiome please send it to me. I want to read and review it. I’ve seen the saturated fat the animal protein evidence and we’ve discussed it so if you know of papers that specifically show that when a human consumes dairy it has a negative effect on the gut microbiome please send it through.

Next time you see someone stating dairy is inherently damaging to the gut microbiome, ask them to send through their research. If you liked this article and think others might benefit from reading it then please share it on your facebook or instagram page. 

Chat soon, 

Marika x

Dustie N Butteiger, Ashley A Hibberd, Nancy J McGraw, Nida Napawan, Janine M Hall-Porter, Elaine S Krul; Soy Protein Compared with Milk Protein in a Western Diet Increases Gut Microbial Diversity and Reduces Serum Lipids in Golden Syrian Hamsters, The Journal of Nutrition, Volume 146, Issue 4, 1 April 2016, Pages 697–705

Singh, R. K., Chang, H. W., Yan, D., Lee, K. M., Ucmak, D., Wong, K., Abrouk, M., Farahnik, B., Nakamura, M., Zhu, T. H., Bhutani, T., … Liao, W. (2017). Influence of diet on the gut microbiome and implications for human health. Journal of translational medicine15(1), 73. doi:10.1186/s12967-017-1175-y