Most people know they should eat more fiber, but getting enough fiber is only part of the picture.
Different types of fiber work differently in the digestive tract.
Some help support regularity. Others are fermented by gut bacteria. Some ferment relatively quickly, while others resist fermentation longer as they move through the digestive tract.
That is why experts recommend getting fiber from a variety of foods rather than relying on a single source.
Fiber Does More Than Support Regularity
Fiber plays several important roles in digestive health.
Depending on the type, fiber can:
- Add bulk to stool
- Help support regular bowel movements
- Absorb water
- Support normal digestive function
-
Help nourish certain beneficial gut bacteria
These effects can vary from one type of fiber to another.
That means two foods can contain the same number of grams of fiber and still behave differently in the gut.
Some Fibers Work Fast. Others Go Farther.
One important difference between fibers is how quickly gut bacteria ferment them.
Some fermentable fibers are used relatively quickly, while others resist fermentation longer and may remain available farther along the colon.
Because fibers are fermented differently, including multiple types can provide the gut microbiome with a wider variety of substrates.
This is another reason relying on a single fiber source may not provide the same variety as a more diverse approach.
Your Gut Bacteria Have Favorites
Your gut contains a diverse community of microorganisms, and different microbes can utilize different types of carbohydrates and fibers.
Certain fibers may support specific groups of gut bacteria, while others may be utilized by different microbial populations.
This helps explain why consuming a variety of fiber sources is generally encouraged.
Instead of thinking only:
“Did I eat enough fiber?”
Try thinking:
“How many different sources of fiber did I eat?”
How to Get More Fiber Variety
Try including fiber from several food groups throughout the week.
Whole grains:
Oats, barley, quinoa and whole-grain breads
Legumes:
Beans, lentils, chickpeas and peas
Fruits:
Berries, apples, pears, kiwi and bananas
Vegetables:
Broccoli, leafy greens, carrots, asparagus and artichokes
Nuts and seeds:
Chia seeds, flaxseeds, almonds and walnuts
Resistant starch sources:
Beans, oats, green bananas and certain cooked-and-cooled starches
Rather than relying on one fiber source, aim to include a variety of fiber-rich foods regularly.
Fiber Quantity Still Matters
Fiber needs vary by age, sex and calorie intake, but common adult recommendations fall around 25 to 38 grams per day.
But instead of getting most of those grams from the same source, try to spread your intake across different foods.
For example:
Breakfast: oats, berries and chia seeds
Lunch: beans, vegetables and whole grains
Snack: fruit and nuts
Dinner: lentils, greens and another whole-grain or vegetable source
This can help increase both your total fiber intake and the variety of fiber you consume.
A More Complete Approach to Fiber.
Fiber is not one single nutrient that works the same way throughout the gut.
Different types can:
- Perform different functions
- Interact with different gut bacteria
- Ferment at different rates
- Be fermented at different points within the colon
That is why including a variety of fiber sources can offer a broader range of functions within the digestive system.
Different fibers have different properties, ferment at different rates, and interact differently with the gut microbiome.
Both fiber quantity and fiber variety matter.
