Gut bacteria may hold the key to helping people benefit from healthy foods

An analysis of more than 50,000 individuals worldwide found that carriage of intestinal Blastocystis, a single-celled organism commonly found in the digestive system but classified as a parasite or harmless organism, was associated with indicators of better cardiovascular health and reduced body fat.

This study cell The study was conducted by an international team led by researchers at Massachusetts General Hospital (MGH).

“Although the health and disease effects of Blastocystis are controversial and likely context-dependent, our study suggests that Blastocystis may play a beneficial role in how diet influences human health and disease,” said co-first author Long H. Nguyen, MD, a physician-investigator in the Clinical and Translational Epidemiology Unit and Department of Gastroenterology at MGH and assistant professor of medicine at Harvard Medical School. “At the very least, its ubiquity may suggest a nonpathogenic role.”

Nguyen, who is also a Transformational Scholar in the Chen Institute School of Medicine at MGH, and his colleagues sought to establish the relationship between Blastocystis in the gut, nutrition, and subsequent cardiometabolic health outcomes such as overweight/obesity, type 2 diabetes, and cardiovascular disease.

To do so, the researchers conducted a large-scale study combining and harmonizing data on nearly 57,000 individuals from 32 countries across North and South America, Europe, Asia and Africa, focusing on Blastocystis and investigating whether its presence alters the effects of different diets on an individual’s cardiometabolic health.

“We found that the presence and abundance of Blastocis varies from region to region and is influenced by diet,” Nguyen said.

Blastocystis was associated with the consumption of certain foods and an overall dietary pattern favouring healthier plant-based and less processed foods. Furthermore, Blastocystis was rarely found in newborns, suggesting it was likely acquired later in life, and it was found in a stool from AD 595, suggesting that it is not strictly a marker of modern microbiome composition.

Notably, higher levels of Blastocystis were associated with better short-term indicators of cardiometabolic health. For example, the team observed that people with higher levels of Blastocystis had more favorable blood glucose and lipid profiles, suggesting that this may be in addition to the effects of a healthy diet, which may have a positive impact on cardiometabolic health. Lower levels of Blastocystis were also associated with longer-term outcomes, such as obesity.

Additionally, improvements in diet quality were associated with subsequent increases in Blastocystis prevalence and abundance in adults participating in a 6-month individualized dietary intervention study.

“Overall, our findings suggest a potentially beneficial regulatory role for Blastocystis, which may help explain differences in individual responses to diet and digestive health depending on the presence and levels of Blastocystis,” Nguyen said.

“Our findings also suggest that Blastocystis is not a parasite with harmful effects on the host, but rather may be a beneficial component of the human gut microbiome.”

Similar to the growing body of research investigating the effects of modulating gut bacteria to prevent a variety of medical conditions, further research is needed to determine whether increasing levels of Blastocystis is a viable disease prevention strategy.