Most people are well aware that fibre is a nutrient we want to eat enough of. Fewer know that there are two distinct types: soluble fibre and insoluble fibre. Both play different but equally valuable roles in your body. Does fibre make you poop? You bet. But as hyped as those particular powers may be, there’s actually a lot more to appreciate about this food group, both in its soluble and insoluble forms.
In an effort to give fibre its full due, we broke it all down with the help of a few nutrition experts. Here’s everything you need to know about the two types of fibre, including what they do in your body, the foods where you can find them and the health benefits they offer.
What actually is fibre?
Fibre, sometimes called dietary fibre, is a type of carbohydrate found in plant foods. Its structure is formed by a bunch of sugar molecules, bound together in a way that makes it hard to readily break down and use as energy. The small intestine can’t digest fibre in the same way as other kinds of carbohydrates, so unlike sugar or starch, for instance, fibre is not a great source of fuel for the body. But it still plays a crucial role in a healthy diet.
What foods are high in fibre generally?
Lots of kinds of plants. Nearly all plant foods (which include vegetables, fruits, whole grains, legumes, seeds and nuts) contain a combination of both soluble and insoluble fibre, according to the FDA. Sometimes, the two types are listed separately on nutrition labels, but often, they’re lumped together as ‘fibre.’ Take an apple, for instance. Its flesh contains some soluble fibre, while the skin is full of insoluble fibre, Whitney Linsenmeyer, an assistant professor in the department of nutrition and dietetics at Saint Louis University’s Doisy College of Health Sciences and a national spokesperson for the Academy of Nutrition and Dietetics (AND), tells us.
Where both types of fibre don’t always show up is in fibre supplements (like psyllium husk products) and fibre-fortified foods (like high-fibre protein bars), which often contain large amounts of added fibre that consists of just one type or the other, Lisa Young, a nutrition counsellor and adjunct professor in the department of nutrition and food studies at New York University, says. That not only denies you the benefits of both types, but can also be less than ideal for your stomach, as we’ll get into in a bit.
What is soluble fibre and what does it do?
Soluble fibre is fibre that is able to dissolve in water. While there are “typically fewer rich sources of soluble fibre in our food supply than insoluble fibre,” Desiree Nielsen, a recipe developer with a focus on plant-based nutrition, explains, you probably still have plenty of decent options sitting in your pantry. Soluble fibre is found in grains (like barley and oats), legumes (like beans, lentils and peas), seeds (like flaxseeds and chia seeds), nuts (like peanuts and macadamia nuts) and some fruits and vegetables (like bananas, avocados, citrus fruits, strawberries and carrots, okra and eggplant). It’s especially concentrated in berries, artichokes, broccoli and winter squash, Kim Larson, a board-certified health and wellness coach, tells us.
