Look, us mere mortals never really get to find out what is going on in the world of science, well, not unless it’s (sometimes) sensationalised in the press. So, we wanted to bring you a snapshot of the latest science to whet your appetite to find out more if it’s something that piques your interest, or simply to keep you all in the “gut world” loop. Remember most of the studies are VERY new science, so keep your critical thinking cap on!
Diet plays an important role in shaping our gut bacteria composition and function which in turn affects our general health. Mediterranean diet, rich in fruit, vegetables, pulses, nuts and fish with moderate or low intake of dairy, meats, and wine, has been recommended as a way to reduce the risks of non-communicable diseases such as obesity, type 2 diabetes, heart disease or cancer. There is little information in humans on the impact of Mediterranean diet intervention on gut bacteria composition and function and metabolism.
This study was published in the Gut Journal and looked at the impact of Mediterranean diet intervention on gut bacteria and general markers of health among overweight and obese people at risk of heart disease.
Type of Study
This was a parallel randomised controlled study where overweight and obese people (men and women) were randomised into 2 groups: 43 participants consumed a Mediterranean Diet adapted to their energy intake and 39 participants maintained their usual diets (control group). This intervention lasted 8 weeks. Participants were asked not to change their physical activity habits throughout the study and they provided urine, blood and faeces at baseline (beginning of the study), 4 weeks and 8 weeks. They kept dietary records that assessed their compliance with the dietary intervention (Mediterranean or control diet).
People on the Mediterranean diet showed a decrease in blood cholesterol levels as a result of their diet when compared to people who were on their usual diets (control group). These benefits were even more obvious among people with higher Mediterranean diet adherence. As a result of consuming more plant-based foods, the number of gut bacteria associated with fibre intake increased whereas gut bacteria associated with inflammation were in lower amounts. Analysis of blood and urine chemicals showed lower levels of bile acids (chemicals associated with intake of meat and fatty foods) and higher insulin sensitivity (lower risk of type 2 diabetes).
The intervention lasted 8 weeks and didn’t have a follow-up and therefore the long-term consequences of the Mediterranean diet on lipid levels, metabolism and gut bacteria composition are unknown. In addition, body weight and composition (fat and muscle masses) were not assessed throughout the study and so we don’t know whether the Mediterranean diet intervention affected these characteristics.
This study indicated that short term adoption of the Mediterranean diet leads to lower cholesterol levels, changes in gut bacteria composition (more bacteria that consume dietary fibre and fewer bacteria associated with inflammation) and lower levels of chemicals associated with meat foods. It’s a great study because it shows how good changes in our diets, even brief ones, affect the gut bacteria composition which in turn benefits our health.
About the Author
Monica Mischie obtained an Msci in Human Genetics from University College London in 2018. She is now doing a Ph.D. on the gut microbiome and dietary fibres at Imperial College London. She loves cooking, discovering new flavour combinations, and visiting farmers’ markets.
If you want to learn more on this topic, gut in touch and simply put “Mediterranean diet and the gut” in the subject matter, we’ll know what you mean 😉 and add it to our content tally mark wall chart. You can also contact us if you’d like a copy of the study.