Soluble Fibre is Magic and it Could Save Your Life or Ruin It
There are two kinds of fibre in the foods we eat. Many people think of fibre as stringy, flaky, tough things like bran, brown rice, or apple skins. Need more fibre in your diet? Eat brown bread!
These fibres are called insoluble fibre. I always made the connection between edible fibre and usable fibre like linen or wood pulp. Fibre must be tough, substantial, and flexible.
That’s only half the story with edible fibres, though, and if you’re having digestive problems, you need to learn about soluble fibre.
“Soluble” in the name means it is a fibre that dissolves in water. When I learned this, it changed my world. If you take a teaspoon of powdered soluble fibre, like inulin, and put it in a cup of water, it will dissolve! You’ll end up with a slightly sweet and maybe slightly tinted cup of water. If you add enough (like a whole container of inulin), you’ll get a gel-like substance.
How is this even fibre and how does it help my guts?
First, let’s go back to insoluble fibre. The digestive tract doesn’t break down these types of fibres. They add bulk to your stool and help your intestinal tract digest other foods properly while preventing constipation. If you’ve ever had to go on a low-residue diet, you’ll know that insoluble fibres are banned.
Many guides on low-residue diets have misleading wording like “avoid high fibre food.” What they mean is: avoid food high in insoluble fibres because these fibres aren’t easily digested in our intestines.
Soluble fibre, however, is helpful for low-residue diets because they help things move along without moving too fast and without leaving anything behind.
Insoluble fibres help lubricate your guts and move things along smoothly—they work by creating a gel that moves through your system as food is digested and helps you have predictable, smooth bowel movements. The gel is formed over time in your guts as the fibre reacts with your stomach chemistry, which causes it to bind together and essentially create a mesh of molecules that traps water.
You have probably seen this gel-formation happen yourself on the stove top. Some soluble fibres bind together very easily. Put on a pot of rolled oats and it will form a creamy, sticky substance. Oatmeal! Add maple syrup and you’ve got breakfast. The same goes for the creamy liquid you get when boiling a pot of rice.
Soluble fibres is basically magic. Having a hard time on the toilet? Add soluble fibre to lubricate the tubes! Having fire hose from your but hole on the toilet? Add soluble fibre to gelatinize some of that liquid.
Fibre and FODMAPs
I have allergies and various FODMAP intolerances, so learning about fibre has been essential to my gut health. Fibres are great, but some fibres are a gut punch for FODMAPs! This means that “more fibre” isn’t always the answer to gut problems because some fibres make things worse for me.
FODMAPs are short-chain carbohydrates that the guts have a hard time absorbing. There is a whole range of science and pseudo-science around FODMAPs that I’ll write about another day. The acronym is often lost on me but the key carbs we care about in FODMAPs are: fructose, lactose, mannitol, sorbitol, galactooligosaccharides (GOS), and fructan. Every person with FODMAP sensitivities has a different experience, so it’s taken me a bit of time to figure out that my top offenders are fructose, sorbitol, and GOS.
This means that I can eat a tiny bit of these carbohydrates and be okay but if consistently eat them I’ll have a very bad time. If the FODMAP is in an insoluble fibre like wheat bran, it can take days to clear the symptoms from my system.
Here are the fibres that have been lifesavers for my flavour of gut issues:
- Carrots: keep the skin on and you get both soluble and insoluble fibre.
- Blueberries: have both types of fibres and taste yummy! Add them to your porridge, yogurt, or salad! Make a compote for your turkey sandwich, or drizzle on your pancakes.
- Chia seeds: not the most exciting on their own but I like the texture of a maple chia pudding (mix chia with milk and maple syrup and place in the fridge overnight). Some people hate the mouth-feel of chia pudding! So treat carefully.
- Agave inulin: this comes in a powder form and can be added to a glass of water or a smoothie. Just let it sit for a few minutes to fully dissolve otherwise it clumps up a bit.
- Oats: rolled or steel cut, but steel cut is my favourite.
Here are some sneaky fibres that have sent me off to the bathroom too many times:
- Apples are a great source of soluble fibre. Boil down an apple and the fibre, pectin, will gelatinize your apple sauce. Yum! Apples are also high in fructose, which destroys my guts. Not Yum!
- Mystery inulin: inulin can come from many sources, artichokes, beans, and chicory to name a few. All three of this hit either an allergy or FODMAP for me. Chicory inulin, for example does THE EXACT OPPOSITE of giving my bowls a smooth ride.
- Metamucil. Big lol at this stuff. How is it even allowed to be marked as The Solution to Your Fibre Needs™. I guess it works for most people but it is PACKED with FODMAP carbs that annihilate me.
- Chicory: I’m adding this to the list twice because it sneaks in to other things. Chicory makes a nice coffee-like flavour when toasted. You wouldn’t think that drinking a nutty tea, or coffee substitute would destroy you. But it does.
On Gluten
Many people say the have gluten sensitivities. This may be true, but it might be more accurate that they have GOS or fructan sensitivities. FODMAP sensitivities are a different challenge from Celiac Disease. While there is some overlap in the symptoms, they require different management techniques.
Gluten is something entirely different from the FODMAP carbohydrates. Gluten is a protein that is created either during baking and cooking, or in the digestive tract. When you knead dough two proteins in flour bind together to make the smooth, elastic texture of the dough. Celiac Disease is an autoimmune disease that causes the body to treat gluten as an enemy foreign substance.
Wheat flour isn’t the only source of gluten. Gluten can be formed by barley, rye, and other cultivars of wheat that claim to be “low gluten.”
For people with FODMAP sensitivities, gluten free grains like buckwheat can set off their symptoms and low gluten grains like spelt can alleviate them. If you suspect you have a gluten sensitivity and it is alleviated by eating spelt breads, you likely have a GOS or Fructan sensitivity instead.
On Lactose
Lactose is a FODMAP but lactose intolerance is different from FODMAP intolerances in general. Lactose intolerance is cause by the body not producing enough enzymes to break down lactose. You can compensate for this by reducing your dairy intake or taking an enzyme supplement.
Conclusion
“Eat more fibre” is bad advice without the rest of the dietary picture. “Eat good fibres” is the better answer and what makes up a “good” fibre might be different for my guts than yours.
I haven’t posted any references in this post because I’ve written this off the top of my head with years of personal experience.
The Monash University’s FODMAP App has been my primary source of research over the years.