by Manisha Kashyap, PhD
A recent study published in Cell (August 29, 2024) has provided a much broader insight into the microbial communities present within the foods we regularly consume and their impact on our human microbiome. Now, a multi-institutional research team has analyzed more than 2,500 metagenomic samples from three different fecal sample collections to identify gut microbes—microorganisms that live in the digestive tracts of animals—specifically associated with the consumption of specific foods. The results have significant implications for food safety, public health, and future study. The open-access Cell article is titled “Unexplored Microbial Diversity from 2,500 Food Metagenomes and Links with the Human Microbiome.”
A Comprehensive Survey of Food Microbes
In this extensive study, led by Niccolò Carlino of the University of Trento (Italy), researchers integrated data from newly sequenced and publicly available food metagenomes to generate curated Food Metagenomic Data (cFMD), a resource that contains metadata, analytical tools, and visualizations for the two major bacteria domains and 30 genera most relevant for processes in foods published by Food Science & Nutrition. The database now comprises more than 10,000 bacterial and fungal food metagenome-assembled genomes (MAGs).
What is very interesting, however, is that 320 of the species identified had never been described before in any other reference database—a large fraction of our knowledge concerning the microbial communities within our food is largely unknown. One intriguing aspect of this work was that almost half the species the researchers found did not have reference genomes. While this means that the study has likely only scratched the surface of which microbes are in our food, it introduces new questions about how these microbes might impact food safety and human health.
Connecting Food Microbes to the Human Gut
But perhaps one of the most important results from this study is connecting food microbes to their potential impacts on the human gut microbiome. Figures reveal that microbes from food account for about 3% of the bacteria found in the average adult gut microbiome. This small percentage, though seemingly modest, plays a crucial role in maintaining the diversity and functionality of gut bacteria.
This study also reveals that certain food-associated bacteria, such as Lacticaseibacillus paracasei, can efficiently engraft in the human gut. This shows that the composition and health of our microbiome are directly influenced by the other organisms we consume in our food, a finding that could literally reshape how we think about diet and nutrition.
Food Safety and Public Health Implications
The broad range of previously undiscovered microbes in food raises the question of how they might affect food safety. Most existing safety guidelines are oriented toward the usual suspects, but finding so many undescribed organisms means that potential new threats could be flying under the radar and need to be explicitly tested. It is possible that this research will make the food safety industry reassess its practices and include these new microbes in their monitoring efforts.
In addition, the metagenomic data integrated within the cFMD resource can serve to develop new tools for food quality and authenticity control. A better understanding of the microbial signatures that distinguish different foods could facilitate traceability, improve our ability to detect food contamination, and even enable targeted interventions that would increase the safety and nutritional value of our food.
Broader Implications for Food Science
The significance of this research initiative goes beyond immediate food safety concerns. The development of the cFMD database is a major advance in the field of food microbiology, providing a curated wealth of data for those studying the microbial communities associated with the production and preservation of foods, as well as how they influence human health.
This new knowledge, discovering hundreds of never-before-seen microbial species, points to a tremendous gap in our understanding that could illuminate the study of microbial specialization on foods. These microbes likely don’t benefit us in any obvious way yet, but they could turn out to be the basis for interesting new probiotic strains or food processing techniques that have yet to be discovered. This research has vast potential implications for both the science of food and its effects on human health.
How Food Microbes Figure into Life
More broadly, the study gives a new perspective on how food microbes engage with the human microbiome in different life stages. This demonstrates to what extent dietary microbes can colonize the intestines in early childhood: whereas this group of microorganisms constitutes only a small fraction of the microbiome in adults, newborns carry them within their gut-residing microbial community from birth on. This early exposure might be important for the development of a healthy gut.
Though the composition of our food-borne microbiome changes as we age, it continues to play a part in gut health throughout life. Other species, like those of the genus Bifidobacterium, are found in all age groups, suggesting a crucial role for long-term gut health, and potentially influencing better protection against different diseases.
Understanding the Study’s Focus on Diet, Microbes, and the Human Microbiome
The relationships between diet and the microbiomes of the human host discussed in this study suggest the importance of looking at nutrition more holistically. The microbial content of our food, not just vitamins and minerals, may be key to the vitality required for well-being. It could spur new dietary guidelines not just for the foods we eat but also for the microbiota we must nurture.
The results of this study also carry potential implications in the formation of public health strategies to curb and manage gut-related diseases. Suggesting that we can combat the obesity and diabetes epidemics by promoting foods that favor a healthy gut microbiome is a case in point, as would be addressing inflamed bowel diseases to critical manipulations on gut microbes.
Discussion
This study successfully introduced the cFMD resource, significantly expanding our understanding of food microbiomes by integrating thousands of newly sequenced metagenomes. The resource highlights 320 newly identified species and shows a meaningful overlap between food and human microbiomes, pointing to a potential evolutionary link.
However, challenges remain in pinpointing direct microbial transmission from food to humans, complicated by person-to-person transmission. Future studies, including targeted interventions and strain-level analysis, are needed to clarify these transmission pathways. Additionally, expanding the diversity of sampled foods could further refine our understanding of food-associated microbes, enhancing food safety, and quality control efforts.
This work lays a solid foundation for further exploration of the intricate relationships between diet, microbes, and human health.
Takeaway Message
Carlino and his colleagues have contributed to our understanding of the way in which diet affects the composition and activity of gut microbes. The research, by mapping out the microbial content of food, uncovers a dimension of diet that had previously gone unnoticed. Given that there is so much to learn from the microbiota of our food, the future in terms of food safety and human health looks bright! This is a huge leap for our knowledge in supporting a healthy microbiome and how good food benefits our health as their interaction.
About the Writer
Dr. Manisha Kashyap (Dr. MK)
BDS (Hons), MSc, PhD (Healthcare)
Manisha Kashyap earned a BS in Dentistry (Gold Medalist) and an MS in Clinical Research, and she is a driven PhD scholar in Health Policy and Management.
With a rich background as a Drug Safety Analyst for top-tier bio pharmaceutical companies, she blends clinical expertise with a passion for advancing healthcare accessibility and innovation through her writing career for the love of science and technology via MedKnow Research Writing Solutions.
Dr. Kashyap’s PhD thesis is on “Artificial Intelligence (AI) and Public Health: Harnessing the Power of AI for Enhanced Public Health Policy and Management.”