Prebiotic Fiber Syrups - Keto Friend or Foe?

I've noticed the inclusion of prebiotic fiber syrups in more and more low carb recipes and retail products, as of late.  These syrups are usually clear, while others are amber, or "gold," and they all consist primarily of IMO, or isomalto-oligosaccharides, a type of plant-derived, prebiotic fiber.  The natural form of this type of long-chain carbohydrate is found in fermented soy, for example.  However, the majority of the IMO syrups contain the processed version; the IMO is extracted from the starch found in various types of grains, and likely genetically modified grains, at that.  IMO’s inclusion by numerous protein bar companies is both frequent and abundant.  Quest Nutrition is no longer one of these companies, though.  Some years ago, in fact, Quest Nutrition deliberately switched from using IMO, to using SCF, or soluble corn fiber, another genetically modified, plant-derived prebiotic fiber.  This was due to a few reasons, including that: 1) SCF extends shelf life, and 2) IMO, per a study conducted by the European Union, raises blood sugar levels comparably to glucose.  

A study in 2003, comparing the digestibility of IMO and two other types of prebiotic fibers, found that IMO was “readily hydrolyzed by small intestinal enzymes” (Oku & Nakamura, 2003).  This finding supports the reliability of a previous finding, by a 1992 study, which saw that IMO is not only absorbed in the gut, but that it also elicits both an insulin response, and a rise in blood sugar (Kohomoto, et. al., 1992).  So, while it's well established in scientific literature that IMO may encourage the growth of "good" gut bacteria, and while these syrups are marketed in America as being both “low glycemic,” and “low-carb friendly,” IMO is likely not the best option in terms of supplemental fiber, let alone as an alternative to sugar.  

At The Ketogenic Baking Company, we feel that the fiber found in many non-starchy whole plant foods, such as avocados, coconuts, nuts, and seeds, are sufficient for good gut health while consuming a ketogenic diet, paleo diet, or any diet, for that matter.  Gra-POW! Cookie Granola contains a nominal dose of fiber per serving when compared with the 28g of fiber that just one serving of a particular brand of IMO contains, but the fiber found in Gra-POW! is of the best kind of source: whole food.


Kohmoto, T., Tsuji, K., Kaneko, T., Shiota, M., Fukui, F., Takaku, H., Nakagawa, Y., Ichikawa, T., Kobayashi, S. (1992). Metabolism of 13C-isomaltooligosaccharides in healthy men. Bioscience, Biotechnology, and Biochemistry (Japan), (6), 937.

Oku, T., & Nakamura, S. (2003). Comparison of digestibility and breath hydrogen gas excretion of fructo-oligosaccharide, galactosyl-sucrose, and isomalto-oligosaccharide in healthy human subjects. European Journal of Clinical Nutrition, 57(9), 1150-1156. doi:10.1038/sj.ejcn.1601666

Bianca Maxwell