Research links specific gut microbe to healthier diets and improved cardiometabolic markers

02 Aug 2024 --- International scientists determined that people with gut Blastocystis — a single-celled organism commonly found in the digestive system — also met indicators of good cardiovascular health and decreased body fat. The team also linked healthier plant-based diets to higher Blastocystis levels. Additional studies are needed to determine if increasing Blastocystis levels could be a viable disease-prevention strategy. 

However, the new study suggests a potentially beneficial role for Blastocystis. While the gut microbiome is critical in the “diet-health axis,” the authors note that the role of micro-eukaryotes (a fraction of microbes) such as Blastocystis is underexplored. They add that their work may help explain personalized host responses to diet, disease causes and development. 

Nutrition Insight discusses the study’s results with two authors, Nicola Segata and Francesco Asnicar, professors and researchers at the Cellular, Computational and Integrative Biology Department of the University of Trento, Italy. 

“For a long time, Blastocystis has been considered a parasite with detrimental effects on host health, while more recent studies found some associations between its presence and better cardiometabolic profiles. However, these studies were limited in size, and the ecological and clinical role of Blastocystis was still considered controversial,” explain Segata and Asnicar. 

“Our work is the first one that gathered and analyzed more than 50 thousand microbiome samples and showed at an unprecedented scale that Blastocystis is commonly present in the gut of healthy individuals and that its presence is linked with healthier diets and lower weight.”

“We hope our results can fuel future research to unravel the role of Blastocystis in our gut microbiome.”

Heart health  
For the study published in Cell, the researchers integrated and harmonized data from 56,989 microbiome samples from people from 32 countries in North and South America, Europe, Asia and Africa. They found that “human Blastocystis exhibits distinct prevalence patterns linked to geography, lifestyle and dietary habits.”

Moreover, higher Blastocystis levels were linked to better short-term markers of cardiometabolic health. For example, the researchers found more favorable blood sugar and lipid profiles in this group, suggesting a potential positive impact on cardiometabolic health beyond a healthy diet. 

Higher Blastocystis levels were linked to better cardiometabolic health markers, e.g., blood sugar and lipid profiles, and lower body fat.Segata and Asnicar explain: “We cannot specifically single out the impact of Blastocystis on better cardiometabolic health profiles. However, we observed that, among individuals with comparable diet quality, Blastocystis-positive individuals tended to have better biomarker values than negative ones.” 

They underscore that this was held when they compared individuals with the same diet quality to rule out the possibility that the effect was an outcome of the diet quality. 

“In addition, we showed that when Blastocystis is present, bacteria associated with favorable cardiometabolic health are also present. Thus, there is more to study about this cross-relationship with Blastocystis and the bacterial species that might impact diet responses and cardiometabolic health together.”

In the long term, lower Blastocystis levels were linked to lower rates of obesity and disorders related to altered gut ecology. 

Dietary patterns 
The study linked Blastocystis levels with dietary patterns favoring healthy, plant-based and minimally processed foods. Moreover, the researchers discovered that the organism was “hardly ever found” in newborns, which suggests that it is acquired later in life. 

The team posits that Blastocystis is not a marker of modern microbiome configuration as it was also found in stool from 595 AD. 

“We analyzed extensive cross-sectional data on dietary habits and observed that people who consume higher quantities of unprocessed, fiber-rich and plant-based foods (such as nuts, seeds, legumes and cruciferous vegetables) have a higher prevalence of Blastocystis,” comment Segata and Asnicar.

“Conversely, Blastocystis-negative individuals tend to consume more frequently highly processed foods (such as fried potatoes, candies and artificially sweetened beverages).” 

Personalized dietary program 
Additionally, the scientists conducted a six-month diet intervention study with 1,124 individuals. During the program, participants received individualized dietary recommendations, and the research team conducted pre- and post-intervention stool sampling. 

Participants improved their diet quality as assessed by a healthy plant-based dietary index and a healthy eating index. Moreover, they lost weight — 0.5 kg monthly, on average.  

People who consume higher quantities of unprocessed, fiber-rich and plant-based foods had a higher prevalence of Blastocystis.These improvements were linked to increased Blastocystis prevalence (31.32% to 33.81%) and abundance. 

Segata and Asnicar add that in the diet intervention, “we observed that the individuals who gained Blastocystis had a significant increase in fiber and fat intake.” 

“However, we have yet to pinpoint which specific food items can foster Blastocystis acquisition or increased abundance in the gut. Indeed, we still don’t know how Blastocystis is acquired and retained in the human gut.”

Inspiring further research 
The scientists underscore that most research on the human gut microbiome focuses on studying the role of bacteria in relation to diet and host health. 

“At the same time, studying other microorganisms such as fungi, micro-eukaryotes and viruses, as well as their role in host health, is often overlooked. With this work, we are showing that the non-bacterial fraction of the microbiome (Blastocystis is a unicellular micro-eukaryote) has an impact on the whole microbial ecosystem and potentially on host health, and thus should be given more attention in future microbiome studies.”

Although Segata and Asnicar note that “Blastocystis presence is positively associated with more favorable cardiometabolic profiles and negatively associated with disorders linked to altered gut ecology,” it is too soon to determine the potential therapeutic implications of the organism. 

“Further research should focus on characterizing genes and underlying functional mechanisms of Blastocystis potentially affecting host health. Moreover, future studies collecting longitudinal data on disease incidence (not available at the moment) may help clarify whether Blastocystis presence impacts disease development.”

By Jolanda van Hal