Understanding Polyols: The 'P' in FODMAP and Their Impact on Digestion

Polyols, the ‘P’ in FODMAP, consist of engineered sugars (or sugar alcohols) that are chemically similar to naturally occurring sugars but tend to have less calories. Before diving into this article, don’t forget to catch up on fermentable oligosaccharides (‘FO’ in FODMAP), disaccharides (‘D’ in FODMAP), and monosaccharides (‘M’ in FODMAP). 

Commonly used polyols include sorbitol, mannitol, and xylitol. Sorbitol is commonly found in diet sodas, xylitol is often seen in sugar-free candies and gums, and mannitol is often found in protein powders and ‘sugar-free’ baked goods. You will find these alcohols most commonly in sugar-free products as they are included as a sugar substitute. You won't often utilize sugar ingredients in a home-cooked meal but will likely find them in processed and packaged foods. 

These sugar alcohols can also help prevent blood sugar spikes. Yale New Haven Hospital expands on this further; sugar alcohols are converted to glucose more slowly and require very little or no insulin to be fully metabolized. Without the glucose spike, these products are a favorite amongst individuals with diabetes or those hoping to cut out sugar from their diet. They are now commonly used in so many products that you probably consume them without even knowing it. A quick side note: not to worry about the title ‘sugar alcohol’; there is no ethanol in these products as opposed to alcoholic drinks. 

Polyols and Digestion: Incomplete Absorption and Potential Gut Discomfort

Unlike regular sugar, polyols are not fully absorbed by the small intestine. This can lead to fermentation by gut bacteria, causing gas,bloating, and diarrhea in some individuals. While the benefit of avoiding a blood sugar spike is great, the potential gastrointestinal side effects are not. For those already responding sensitively to FODMAPs, reducing sugar alcohol ingestion would be a handy intervention to trial. 

According to the National Library of Medicine, if polyols are consumed in too high amounts, water can flood into the intestine in an attempt to dilute the solution, resulting in abdominal cramping, gas, and, ultimately, diarrhea. Sorbitol will likely cause the most severe symptoms (if consumed in high enough amounts), but all polyols can be guilty. 

Xylitol: A Potential Ally with Caveats

Xylitol is often better tolerated than other polyols and might even have some dental health benefits. It can be used as food by the bacteria that live in our gut and can support good microbiome diversity. According to the Microbiome journal, xylitol can also enhance the concentration of short-chain fatty acid propionate, which in turn can help restrict the amounts of Eschiera and Staphylococcus in our guts (bacteria that, if left unattended, can grow out of proportion and cause infections).  

Managing Polyols in Your Diet

Not everyone experiences digestive discomfort from polyols, and individual tolerance can vary. The best course of action is to diligently check food labels, especially if you are already dealing with FODMAP sensitivity. If you are curious to see how you respond to polyols, try consuming one food that contains a sugar alcohol on its own and wait an hour or so before consuming anything else. The key here is consuming them in small amounts and monitoring your gut reaction. 

Another easy way to track polyols is by using FODMAP-friendly applications. If you are looking for more information and guidance, several apps are available. The Spoonful App is helpful at grocery stores, offering a barcode scanning feature to analyze foods on the spot. Additionally, the Monash University FODMAP Diet app provides easy-to-digest FODMAP information and is constantly being updated.

1. _{Eat Any Sugar Alcohol Lately?. Yale New Haven Health Yale New Haven Hospital. (n.d.). https://www.ynhh.org/services/nutrition/sugar-alcohol} 
2. _{Xiang, S., Ye, K., Li, M., Ying, J., Wang, H., Han, J., Shi, L., Xiao, J., Shen, Y., Feng, X., Bao, X., Zheng, Y., Ge, Y., Zhang, Y., Liu, C., Chen, J., Chen, Y., Tian, S., & Zhu, X. (2021, March 18). Xylitol enhances synthesis of propionate in the colon via cross-feeding of gut microbiota. Microbiome. https://pmc.ncbi.nlm.nih.gov/articles/PMC7977168/}