Fiber is crucial to the health of human beings and yet almost all of us under-consume this key substance. One of the reasons for this, explains a new study, is that few of us understand the importance of fiber in the first place, so the experts want to break it down.
Currently, the predominant classification of fiber is “soluble” and “insoluble,” simply separating soluble foods like lentils, seeds, and fruits like apples from the insoluble foods such as whole wheat, grains and some vegetables.
What is the Difference Between Soluble and Insoluble Fiber?
Soluble fiber absorbs water and dissolves into a gel, slowing digestion, whereas insoluble fiber is heavier and helps food to pass more quickly through the stomach and intestines. The problem? These two classifications are too simplistic. For example, fiber can also be divided into substances that easily ferment, and therefore reduce cholesterol, but it gets complicated because these fibers can be either soluble or insoluble. To that end, a team at RMIT University in Australia have published a study that seeks to highlight the many benefits of fiber that go beyond a simple two item classification.
“Quite like how different medicines target different conditions, so too do different types of fibers,” explained RMIT University food scientist Professor Raj Eri. “Our research is helping to understand which type of fibers we should eat to help address certain ailments.”
The New Way of Classifying Fiber
The Australian experts advise augmenting the current understanding of fiber by dividing it into five key features:
- Backbone structure
- Water-holding capacity
- Structural charge
- Fiber matrix
- Fermentation rate
“For example, suppose you want to promote colonic health. In that case, you identify a fiber’s properties as defined by the bottom-up approach, which align with your desired outcome – in this case fermentation rate,” said Christo Opperman, the study’s lead author. “Applying this framework can assure consumers, dieticians, clinicians and food technologists that they are receiving their desired health effect, which previously was a vague guessing game.”
Making fiber more of a fundamental part of our diet is essential. “In the countries surveyed, including Europe and the USA, every single population had a deficiency of fiber,” explained Professor Eri. “Considering fiber is one of the most important nutrients, this is extremely worrying.”
He’s right. The recommended dietary fiber intake for adults is 28-42 grams per day, but American’s only average 12-14 grams, and Europeans fair little better with 18-21 grams per day. The accessibility of fast and processed foods is moving us away from the natural whole foods that are abundant in fiber, and most people don’t even realize the trade off between convenience and maintaining a healthy diet.
“Our framework is an essential step in addressing this gap,” said Eri, pointing out that health and diet companies would then be able to tailor brand messaging around specific health benefits of fiber, reaching the consumer in a more targeted way. Work is now underway to understand these classifications and the full range of benefits better, so that they can help bolster our knowledge of this crucial nutrient.
