According to a 2021 study, 94% of Americans don’t consume enough fiber.
Considering the popularity of low-carb diets today, this statistic isn’t surprising; after all, fiber comes from carbohydrates. It doesn’t come from protein and fat.
What does come as a surprise to most people is the numerous aspects of health that depend on an adequate and consistent intake of fiber.
In fact, failing to get an adequate intake of fiber increases the risk of numerous diseases and even early death.
What is fiber?
As a non-digestable carbohydrate, fiber passes through the body without being broken down. This aids digestion, contributes to keeping bowel movements regular, and helps carry contaminants out of the digestive tract—among other metabolic functions.
According to Cleveland Clinic, fiber is essential for “preventing constipation, lowering cholesterol and blood sugar, and reducing the risk of chronic diseases.”
Cedars-Sanai states: “An adequate fiber intake is associated with reduced risk for heart disease, stroke, hypertension, certain gastrointestinal diseases, obesity, type 2 diabetes, and certain cancers.”
Fiber intake is so important the National Academy of Medicine has established the “adequate intake”—the amount necessary to to keep digestion optimized and bowel movements regular. Currently the recommendation is 14 grams of fiber for every 1,000 calories consumed.
Meeting this recommendation is where Americans fail dismally, with only 6% of the population consuming the adequate intake.
Fiber and the gut health
Perhaps the most important benefit of fiber is that it serves a “prebiotic” function—providing a substrate that is selectively used by microorganisms in the gut to grow and expand.
Fruits and vegetables are natural food sources of prebiotics, and since the majority of Americans favor processed foods over fruit and veggies fiber supplements have become a popular alternative.
Two notable examples are inulin and psyllium. Inulin is a naturally-occurring polysaccharide fiber that is produced by many types of plants. Industrially it is most often extracted from chicory.
Psyllium is the common name used for several members of the plant genus Plantago. Psyllium is mainly harvested for use as a dietary fiber—both medicinally and for nutritional supplements.
Unfortunately, these types of supplemental fibers, while beneficial in providing fiber, are “isolated” nutrients and lack the other health-promoting compounds (such as polyphenols) found in fruits and vegetables.
New study
But now there’s a solution. Thanks to new research we now know that special blending of a specific mix of high-polyphenol fruits and veggies provides a more effective fiber/prebiotic supplement.
In a study published in Microorganisms in March 2025, researchers from Belgium and the U.S. evaluated the impact of a proprietary blend of fruit and vegetable fibers on the gut microbiome of test subjects. The results were compared to test subjects provided purified fibers—inulin and psyllium.
Samples were assessed for acidity, gas pressure, short-chain fatty acid production, lactate, and ammonium at start time and 48 hours. Gut flora—termed as “microbial community composition”—was also assessed at regular intervals.
Superior benefits documented
The researchers found all test products fermented well in the colon as demonstrated by decreases in acidity and increases in gas pressure over time.
However these changes occurred faster with the purified fibers, while the proprietary blend of natural fruit and vegetable fibers demonstrated slow, steady changes.
In this situation slower is better, the researchers noted, because it indicates “a gentler fermentation process.” This is important since it reduces the bloating and discomfort that frequently accompanies fiber supplementing.
Short chain fatty acid production also increased more significantly over 48 hours with the fruit and veggie blend compared to the purified fibers.
Finally, overall improvement in the microbial community composition were observed with both the proprietary blend and purified fibers; however, the bacterial abundance and richness found in the interior of the gastrointestinal tract was significantly greater with the fruit and veggie blend.
The researchers reported that the positive results were demonstrated with just two grams of the fruit and veggie blend.
The proprietary natural fruit and vegetable fiber blend used in the study can be found in Optimal Complete Nutrition Plus from Optimal Health Systems. Click the banner ad on this page to learn more.
Optionally, fermented fiber has the ability to help your body regulate appetite. Find fermented fiber in Optimal Fiber GLP-1, also available from Optimal Health Systems.
– – –
Primary source: Microorganisms, March 2025.
PDF download of study available here.
