What is Inulin?
Inulin is a type of carbohydrate indigestible in the stomach and small intestine. It is, however, fermented in the large intestine (colon) with the help of bacteria. Inulin is nutritionally important because it is a soluble fiber and a prebiotic. It is a low energy (calorie) food. Compared to the same units of digestible carbohyrates, it provides only 25 - 35% calorie. It is found in a wide variety of plants such as vegetables, fruits and cereal grains.
Health Benefits of Inulin
Inulin is a dietary fiber, a soluble fiber. When you eat food high in inulin, you reduce the calorie gain, since it passes the small intestine undigested and thus reduced supply of calorie to the body. Also because of its soluble fiber nature, it reduces risks of constipation and increases stool bulk. Scientists estimate for every 1 gram inulin consumed, there is an increase by 1.5 - 2 grams of wet feces.
Inulin may help lower LDL and total cholesterol level. As a prebiotic, it is promotes gut bacteria growth and as a result, it improves overall health.
Inulin may also increase the absorption of minerals from diet. Studies on rats fed with inulin showed higher absorption of calcium and magnesium.
Inulin is important ingredient in processed foods including dairy, meat and breakfast cereals. It is used as fat and sugar replacement, increase fiber content and prebiotic.
Foods High in Inulin
Inulin is a component of plant cell walls and therefore, it is found in a variety of vegetables, fruits and cereal grains. Chicory is high in inulin and is a major inulin source for the food processing industry. Other good inulin sources are artichokes (Jerusalem), banana, dahlia. Below is a list of high inulin food sources and their approximate inulin content.
| Inulin source | Inulin content (g/ 100 g food) |
| Yacon (jicama) roots | 35 |
| Sweet leaf (stevia) | 18 - 23 |
| Garlic, Chinese garlic, bulbs | 14 - 23 |
| Barley grains | 18 - 20 |
| Chicory roots | 11 - 20 |
| Jerusalem artichoke tubers | 11 - 19 |
| Asparagus | 15 |
| Dahlia roots | 10 - 20 |
| Brazilian ginseng (suma) | 11.5 |
| Onions and shallots | 5 - 9 |
Sources:
Shoaib M, Shehzad A, Omar M, Rakha A, Raza H, Sharif HR, Shakeel A, Ansari A, Niazi S (2016). Inulin: Properties, health benefits and food applications. In: Carbohydr Polym. 2016 Aug 20;147:444-454.
Chaito C, Judprasong K, Puwastien P (2016). Inulin content of fortified food products in Thailand. Food Chem. 2016 Feb 15;193:102-5