Fructans are a type of carbohydrate found in a wide variety of commonly consumed foods. While these plant-based compounds offer certain health benefits, their digestion can be challenging for some individuals. This can lead to digestive discomfort, prompting a closer look at how these carbohydrates are processed within the human body. This article will explore the nature of fructans and the biological processes involved in their breakdown.
Understanding Fructans
Fructans are carbohydrate polymers primarily composed of fructose units. These units are typically linked together, often with a glucose molecule at one end of the chain. Fructans function as energy storage carbohydrates in many flowering plants, similar to how starch or sucrose serve this role in other plants.
Many common foods are significant sources of fructans. These include grains such as wheat, barley, spelt, and rye, which are major dietary contributors. Fructans are also abundant in various vegetables like onions, garlic, leeks, asparagus, artichokes, and Brussels sprouts. Certain fruits, including watermelon, persimmon, and ripe bananas, also contain these carbohydrates. Additionally, fructans like inulin are sometimes added to processed foods to increase fiber content, acting as prebiotics.
The Enzyme Responsible for Fructan Breakdown
The human digestive system does not produce the specific enzyme required to break down fructans in the small intestine. The enzyme capable of hydrolyzing the complex bonds within fructans is known as inulinase, also referred to as fructan hydrolase.
Inulinase is a type of hydrolase that breaks the complex bonds within fructan molecules. This enzyme is primarily found in plants and various microorganisms, where it helps in the metabolism and degradation of fructans. Without this particular enzyme in the human small intestine, the long chains of fructose in fructans remain intact as they continue their journey through the digestive system.
The Digestive Process of Fructans
Undigested fructans travel to the large intestine, where they encounter resident gut bacteria.
The gut bacteria ferment the fructans, using them as a food source. This fermentation process leads to the production of various gases, including hydrogen, methane, and carbon dioxide. Additionally, short-chain fatty acids are produced, which can be beneficial to gut health.
However, the gas production, along with fructans’ ability to draw water into the large intestine, can lead to uncomfortable symptoms. These symptoms commonly include bloating, increased gas, abdominal pain or cramps, and altered bowel habits such as diarrhea or constipation. Such digestive discomfort is particularly noticeable in individuals with conditions like Irritable Bowel Syndrome (IBS).
Supporting Fructan Digestion
To help manage the digestive discomfort associated with fructan consumption, external means can be considered. Enzyme supplements containing fructan hydrolase (inulinase) are available. These supplements provide the enzyme the human body lacks, assisting in the breakdown of fructans into simpler sugars before they reach the large intestine, which can lessen fermentation and associated symptoms.
These enzyme supplements may be beneficial for individuals who experience digestive issues after consuming fructan-rich foods, such as those with fructan intolerance or IBS. While enzyme supplementation focuses on aiding breakdown, dietary strategies also play a role in managing fructan intake. A low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) diet is one approach that involves reducing the consumption of foods high in fructans and other fermentable carbohydrates. This dietary approach can help identify specific food triggers and provide relief from symptoms.