It seems like a lot of nutrition messaging centers around the macros: protein, fat, and carbohydrates. But there's a subset of carbohydrates that's worth paying attention to—fiber. There are two types of fiber with a wide range of distinct functions—soluble fiber and insoluble fiber—and here, we'll dig into the superpowers of each one.
Even though fiber might be one of those things that you remember seeing in a canister on your grandma's countertop, it's an important dietary element no matter what your age. Here are answers to some of the most frequently asked questions about fiber.
What is soluble fiber? Functions and benefits
Soluble fiber attracts water and expands into a gel-like texture. Have you ever made a chia pudding or a vegan egg replacement using ground flax and water? Then, you've seen soluble fiber in action.
How does that translate when you eat it? Soluble fiber works in your body by attracting water into your digestive tract, while binding a portion of the fat and cholesterol. As a result:
- You may not absorb as much fat and cholesterol as you consume alongside it
- Slower digestion may lead to lower blood sugar
- Over time, you may see improved blood sugar markers
As a bonus, soluble fiber feeds friendly gut bacteria, and a strong microbiome does wonders for overall well-being.
Soluble fiber food sources
Foods that contain soluble fiber include:
- Chia seeds
- Citrus fruits
- Artichokes, and other fruits and vegetables.
Psyllium husk also contains soluble fiber, which is why it’s a common ingredient in fiber supplements.
What is insoluble fiber? Functions and benefits
Insoluble fiber does not dissolve in water. This type of fiber is found in wheat bran, whole grains, and some fibrous vegetables. Insoluble fiber helps to add bulk to the stool, which could help if you're dealing with loose stools, and at the same time helps keep things moving if you're dealing with constipation.
Benefits of insoluble fiber include:
- Helps make your waste elimination more efficient
- May improve lower digestive system
- May help with constipation
- Could help you avoid certain conditions associated with inefficient bowel function
- May reduce the appearance of bloating if bloat is a result of inefficient elimination
Sources of insoluble fiber
Sources of insoluble fiber include wheat bran, rice bran, some vegetables, and nuts.
Choosing wheat bread over white bread, or wild rice over white rice will help you get a little extra dietary fiber.
Which is better, soluble or insoluble fiber?
Is one type of fiber better than the other? The short answer is no. Even though they are both classified as fiber, soluble and insoluble fiber have distinct functions and are both important for maintaining a long list of body functions.
Your best bet is to eat a combination of both by working a wide range of fruits, vegetables, grains, nuts, and seeds into your diet.
How much fiber do you need?
The USDA recommends 14 grams of fiber per 1000 calories of food. They do not specify which type of fiber should be included and in what proportion.
The Cleveland Clinic breaks out fiber recommendations according to gender and age as follows:
- Women under 50 should consume at least 25 grams of fiber per day
- Women older than 50 should try to get at least 21 grams of fiber per day
- Men under 50 should aim for 38 grams of fiber per day
- Men older than 50 should consume at least 30 grams of fiber per day
Some sources suggest you eat three times as much insoluble fiber as soluble. Other experts favor soluble fiber because of the long list of health benefits. There are no formal dietary guidelines recommending you go either way. Your overall fiber count is more important.
Your individual needs may be different, so talk to your doctor or a registered dietitian to find out what your ideal targets are.
Can you have too much fiber?
It is possible to have too much fiber. Getting too much fiber can cause bloating, gas, and belly pain.
You're more likely to go overboard with fiber in the form of supplements than from food sources. A big pile of vegetables or a giant bowl of whole grains will likely make you feel full before you consume so much fiber that you start to feel any unpleasantness from it.
The bottom line is, fiber is just as important to be aware of as protein, fat, and other carbohydrates. Most people don’t need to track grams, but aiming to get more fiber is usually a good idea. You can never go wrong with eating more vegetables!