Paleo diet: does it really benefit gut microbiome?

Some of you may have had at some point an experience with Paleo diet as it’s been a popular dietary plan the past years. Short for Paleolithic diet, Paleo requires eating only foods our ancestors would eat, mimicking their nutritional habits. This means no bacon, chips and generally no processed foods and dairy, which is a good thing. At the same time, though, healthy food groups like legumes and whole grains are also excluded and there’s a lot of emphasis in animal protein through meat consumption, which takes us far away from a plant-based model of nutrition, which is scientifically beneficial for gut microbiome and immune support.

What is rather ironic is that Paleo diet was considered for years an ideal choice for gut health, but with no actual research behind this statement. Until this Australian published research in European Journal of Nutrition (July 2019) set things straight, proving that following a strict Paleo diet can be far from beneficial for the gut. In fact, it’s harmful. (1).

There were three groups in this long-term, cross-sectional study: a Paleo group of 44 people divided in two, where one group followed a strict Paleo diet (22 people) and the other, the pseudo-Paleo (also 22 people), was rather loose, and also a control group, consisting of 47 people which followed a typical diet based on national Australian recommendations. The objective of the study was to determine the association between diet and markers of gut health, microbiome and serum trimethylamine-N-oxide (TMAO), which is a gut-derived metabolite associated with cardiovascular disease.

The good, the bad and the… gut
Researchers found that there were three types of bacteria in the three groups in different proportions, with the control group being significantly different in their presence in the gut than the other two Paleo groups.

More specifically, healthy bacteria Bifidobacteria and Roseburia, which play an important role in gut homeostasis and health (2), help metabolize complex carbs to produce short-chain fatty acid, protect form obesity and IBS (3), leaky gut while they promote anti-inflammatory bacteria and tune in our immune system, were found in greater quantities in the control group, while the Paleo groups were short of them.  

Roseburia bacteria which fight inflammatory bowel diseases like Crohn’s disease and ulcerative colitis were also found in greater abundance in the control group, but what’s even more interesting is that among the two Paleo groups, the one which followed the strict Paleo diet had lower levels of the good bacteria in relation with the other Paleo group, which was more loose in the Paleo recommendations.

But when it comes to unhealthy bacteria in gut microbiome, the results are once again against the Paleo dieters. TMA-producer bacteria Hungatella, which leads to trimethylamine-N-oxide or TMAO production (an organic compound formed after the consumption of choline, a nutrient found in red meat, eggs, fish, and poultry) was found in significantly higher levels in the two Paleo groups, compared with the control group, raising the possibility of coronary artery diseases, kidney diseases, type 2 diabetes, stroke, Alzheimer’s and other serious chronic conditions.

It seems that Hungatella leads to higher TMAO levels and although the three groups consumed more or less the same quantities of meat, the lack of whole grain consumption in the Paleo groups seemed to play an important role. While the control group consumed meat, the consumption of whole grains led to lower levels of TMAO, as serum TMAO concentrations and Hungatella abundance were inversely associated with total and whole grain consumption. This inevitably indicates that these food groups may downregulate the ability of Hungatella to dominate or interfere with the production of TMA. Whole grain consumption was also linked to greater abundance in healthy Roseburia and Bifidobacteria.

The Pesudo-paleo group which consumed more fibre than strict Paleo group came in second with lower levels of TMAO compared to strict Paleo, which shows that following a strict Paleo diet is certainly not good news for gut microbiome and immune system.  

There are certainly some good points in Paleo diet, as processed foods are excluded, but the exclusion of legumes and whole grains is certainly harmful for gut health. Stick to a whole food plant-based diet with lots of fruit, vegetables, whole grain, legumes, seeds and nuts in varieties and you’ll soon realize you need nothing more -and nothing less- in your plate and your system.

Whether you have gut problems or want to support your immune system by eating healthier and adopting an immunity-friendly lifestyle, click on our website and you’ll fine everything you need.