- It is general knowledge that the gut microbiome plays an important role in a person’s overall health.
- What we eat is what helps shape the composition of our gut microbiome.
- Researchers from Università di Trento have found that regardless of what type of diet you follow, it’s the food quality and diversity that appear to have the biggest impact on the structure of the gut microbiome.
Over the last few years, it has become general knowledge that the gut microbiome plays an important role in a person’s overall health.
Past studies show that an imbalanced gut microbiome may lead to health issues such as inflammatory bowel disease (IBD), type 2 diabetes, cardiovascular disease, and
“We know that the gut microbiome, with its roles in breaking down certain compounds and synthesizing other molecules, mediates part of the effect that diet has on our body and our health,” Nicola Segata, PhD, professor and principal investigator at the Department of Cellular, Computational, and Integrative Biology (CIBIO) at Università di Trento in Italy explained to Medical News Today.
“So understanding how diet shapes our microbiome and consequently how the combined effect of diet and the microbiome regulates our metabolism and ultimately our health is of primary importance,” he said.
“However, each person’s microbiome is very ‘personal’ — two individuals may share over 99.9% of their human genome, but they usually share less than 5% of the genetics of their microbiomes — and also each person’s diet is both complex and unique,” Segata continued. “Therefore, it is very difficult to map the specific links between diet and the microbiome. So while we know that diet hugely influences our microbiome, we are still far from a clear and precise understanding about how it is influenced.”
Segata is the senior author of a new study recently published in the journal Nature Microbiology, which suggests that whether you’re following a vegan, vegetarian, or omnivorous diet that includes both plant and animal-based foods, it may be the quality and diversity of the diet — rather than the dietary pattern itself — that impacts the structure of your gut microbiome.
For this study, researchers analyzed the gut microbiomes of more than 21,000 people following vegan, vegetarian, or omnivorous diets living in the U.S., U.K., and Italy.
The personalized nutrition program company ZOE Limited partly funded the research, and Segata is on its advisory board and a consultant. Several other study authors have affiliations with or financial interests in the company, while others declare no competing interests.
When comparing the gut microbiomes of participants following the three different diets, scientists observed that those following an omnivorous dietary pattern had higher concentrations of bacteria associated with meat digestion, as well as bacteria associated with IBD and an increased risk of colon cancer, such as Ruminococcus torques and Bilophila wadsworthia.
“It’s important to underline that individuals with increased amounts of those microbes do not generally have IBD and colorectal cancer, but according to other studies those microbes might be a sign of an increased risk for developing those conditions. It is well-known that red meat is a risk factor for colorectal cancer, for example, and the microbes we found higher in individuals eating more red meat could be part of the reason, even though our work did not focus directly on the effects of the microbes on health.”
— Nicola Segata, PhD
The researchers observed that species diversity was lower in vegetarians and vegans than in omnivores. This might sound concerning, but diversity may not be the best measure of microbiome health, as it does not consider the types of microbes present. For example, if an individual has a greater variety of harmful bacterial species, they may have a more diverse but unhealthy gut microbiome.
In fact, when examining the gut microbiomes of vegans, the researchers observed that they included several species of helpful bacteria, such as Bacteroides and Firmicutes phyla. These bacteria aid in producing
The participants’ gut microbiome signatures were also associated with cardiometabolic health, with vegans and vegetarians having microbiome signatures linked to more favorable cardiometabolic health markers than omnivores.
“Our study indeed confirmed that plant-based foods boost microbes that — based on what we know from other studies — are generally able to produce immunomodulatory metabolites,” Segata said. “While some of these microbes are relatively well known, others were previously unidentified or even completely unknown to microbiologists, and our study provides a much more comprehensive map of such microbes. Interestingly, some of these newly associated microbes are so little characterized that they lack a formal name, which underscores the need for further research.”
“Importantly, it is not necessarily the vegan dietary pattern itself that boosts short-chain fatty acid producers, but rather the amount and diversity of plant-based foods consumed. This was confirmed in omnivores because omnivores, as those with higher proportions of plant-based foods in their diet also had higher levels of short-chain fatty acid producers,” he explained.
More fiber, more diversity in gut bacteria“The greater the variety of plant-based foods we consume, the greater the diversity of beneficial microbes in our gut. This is because different plant-based foods contain different types of fiber, and each fiber can stimulate the growth of different types of health-promoting microbes. These microbes work together to improve our gut health, so the more diversity of health-associated microbes in our gut microbiome, the better our chances of good gut health.”
— Nicola Segata, PhD
MNT spoke with Rudolph Bedford, MD, a board certified gastroenterologist at Providence Saint John’s Health Center in Santa Monica, CA, about this study.
Bedford indicated that the gut microbiome profile of vegans and vegetarians might contribute to improved food digestion and better health outcomes.
“Something called metabolic syndrome seems to be less in vegans (and) cardiovascular diseases are also less in vegans, all (seemingly) based upon the change in the gut microbiome itself,” he noted.
Bedford said it is important for researchers to continue to examine how different diets might impact the gut microbiome as medical professionals may one day be able to tell what particular diet to follow to mitigate various diseases.
“If you can explore the genetic variations that influence the gut microbiome in response to these diets, you can essentially personalize nutritional recommendations, and therefore even change the Health of individuals,” he added.
MNT also spoke with Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, for tips on what readers should eat to keep their gut microbiomes as balanced and Healthy as possible.
Richard said that she emphasizes to her clients and patients the importance of diversity and quality in the diet in order to nourish and nurture gut Health and microbiota flora.
“Food groups such as vegetables are important but also the variety within those food groups are key. For example, the Brassicas (Brassicaceae) family (brussel sprouts, cauliflower, kale, collards, cabbage) have numerous benefits related to gut and immune Health, whereas a small amount of iceberg lettuce shreds will not have the same level of beneficial nutrients and interaction in the gut. Most Americans are not consuming the recommended amount of servings of fruits, vegetables, and whole grains in a day and are often over-consuming animal, dairy and ultra-processed foods,” she explained.
How to divide your plate“A visual recommendation is to think about our plate in four equal quadrants. One being for lean protein (fish, poultry, beans, etc.), one for whole grains or a starch (oats, quinoa, potato), one for vegetables (cabbage, broccoli, carrots), and one for fruit (berries, pineapple, apples). If each of these quadrants is represented by different foods within the food groups per meal and possibly enhanced with the added benefits of spices or herbs our nutritional needs will be met and gut bacteria may be doing a happy dance.”
— Monique Richard, MS, RDN, LDN
“Remember, what is good for your body, is good for the gut. It is not about eliminating entire food groups, having a pristine ‘clean’ diet or feeding the gut bugs — it is about nourishing your body from the inside out and the outside in with quality and love,” she added.
