What is this study about?

The importance of carbohydrates in the diet is well established. Their role in caloric transfer is critical to human health, but this simple view does not accurately reflect their important biological activities. Increased consumption of carbohydrates that resist digestion by the host, typically termed “dietary fiber,” has been associated with a reduced risk of obesity, type 2 diabetes, certain gastrointestinal disorders, and coronary heart disease1. Even monosaccharides, the smallest carbohydrate unit, have their own inherent activities in the body2,3. More recently, the ability of indigestible carbohydrates to influence the gut microbiome has become of considerable interest for human health4, 5.

The reality is that carbohydrates are a very large number of compounds, each with their unique structural variations and potentially specific activities7. Thus, the advice “eat more fiber,” is unclear because fiber from two different sources of food can have completely different monosaccharide compositions, bond linkages, degree of polymerization (number of single monosaccharides linked to one another), and in turn, biological functions. Some important functions of carbohydrates include guiding the gut microbiome and through this mechanism protecting the host from pathogens, educating the immune system, regulating metabolism, and fueling nerve growth and repair. The key is to understand the interactions between structures of food carbohydrates and intestinal functions and health.

The purpose of the GENIUS Study is to generate an annotated library of the structure-function relationships of a diverse gut microbiome of stool from healthy adults and plant-derived carbohydrates using specialized chambers in the laboratory called bioreactors. This annotated library will help us identify the foods to use in our future feeding and gut microbiome studies designed to determine the foods to eat to support a healthy gut microbiome.


  1.  Anderson, J. W.; Baird, P.; Davis Jr, R. H.; Ferreri, S.; Knudtson, M.; Koraym, A.; Waters, V.; Williams, C. L., Health benefits of dietary fiber. Nutrition Reviews 2009, 67 (4), 188-205.
  2.  Gonzalez, P. S.; O’Prey, J.; Cardaci, S.; Barthet, V. J. A.; Sakamaki, J.-i.; Beaumatin, F.; Roseweir, A.; Gay, D. M.; Mackay, G.; Malviya, G.; Kania, E.; Ritchie, S.; Baudot, A. D.; Zunino, B.; Mrowinska, A.; Nixon, C.; Ennis, D.; Hoyle, A.; Millan, D.; McNeish, I. A.; Sansom, O. J.; Edwards, J.; Ryan, K. M., Mannose impairs tumour growth and enhances chemotherapy. Nature 2018, 563 (7733), 719-723.
  3.  Koszinowski, U. H.; Kramer, M., Selective inhibition of T suppressor-cell function by a monosaccharide. Nature 1981, 289 (5794), 181-184.
  4.  Riaz Rajoka, M. S.; Shi, J.; Mehwish, H. M.; Zhu, J.; Li, Q.; Shao, D.; Huang, Q.; Yang, H., Interaction between diet composition and gut microbiota and its impact on gastrointestinal tract health. Food Science and Human Wellness 2017, 6 (3), 121-130.
  5.  Barratt, M. J.; Lebrilla, C.; Shapiro, H.-Y.; Gordon, J. I., The Gut Microbiota, Food Science, and Human Nutrition: A Timely Marriage. Cell Host Microbe 2017, 22 (2), 134-141.
  6.  Tungland, B.; Meyer, D., Nondigestible Oligo‐ and Polysaccharides (Dietary Fiber): Their Physiology and Role in Human Health and Food. 2006; Vol. 1, p 90-109.
  7.  Slavin, J., Fiber and prebiotics: mechanisms and health benefits. Nutrients 2013, 5 (4), 1417-1435.