Pilot study links One.bio oat fiber to metabolic, gut and mental health benefits

A 14-day pilot study on One.bio’s oat fiber reveals that the ingredient is a well-tolerated and functional source of fiber with benefits in metabolic, digestive, and mental health. 

Matt Amicucci, Ph.D., co-founder and chief science officer of One.bio, tells Nutrition Insight that the study’s breadth, in a healthy adult population and a short open-label trial, indicates that the biological activity of One.bio 01 oat fiber is “real and measurable.” 

“The result that stands out most is the time-in-range data,” he adds. “Participants taking 10 g or 20 g per day increased the time their blood glucose stayed within healthy ranges by about 14 percentage points over two weeks, reaching approximately 95% of the time in range. This is a significant metabolically meaningful outcome for a fiber ingredient.” 

Amicucci details that the company developed the ingredient in the lab by predicting which fiber structures would feed which microbes, and what those microbes would do in the body. He underscores that the study is the first peer-reviewed clinical evidence for this process, with measurable health outcomes in real people. 

“The predictions held up in a human trial. That’s what makes the work ahead repeatable and scalable.”

Moreover, he adds that the biological processes driving these changes, such as microbiome adaptation, short-chain fatty acid (SCFA) production, and GLP-1 stimulation, deepen with continued use. 

Amicucci says One.bio 01 oat fiber improves blood glucose time-in-range by 14 points through microbiome adaptation.The pilot study evaluated the gastrointestinal tolerance and functional benefits of One.bio 01 oat fiber in 63 healthy adults, who received 5, 10, or 20 g of the fiber per day. 

Metabolic health impacts

The research paper notes that both 10 g and 20 g daily doses “were associated with significant improvement in glycemic metrics.” These included reductions in glucose mean, all glycemic excursions, and an increase in time-in-range.

“There are two mechanisms that we are looking at here — though more extensive in vivo work will have to be done to prove out each of their contributions to the big picture,” adds Amicucci. 

“One mechanism runs through the gut microbiome. When One.bio 01 oat fiber reaches the large intestine, it selectively feeds microbes that produce SCFAs, particularly butyrate.” 

“Butyrate triggers receptors in the gut lining that stimulate the release of GLP-1, the same hormone that the most-prescribed appetite-regulating drugs are designed to mimic, which also promotes insulin regulation. Fiber restores the biological process that those pharmaceuticals are trying to replace.” 

Amicucci says that the second mechanism is microbiota independent, pointing to a 2024 study by the company that demonstrated that short-chain beta-glucans can inhibit the activity of starch-degrading enzymes and glucose transporters in the gut. He notes this slows glucose digestion and absorption. 

“The clinical data align with these proposed mechanisms,” he adds. “At the 20 g/day serving, participants saw statistically significant reductions in peak post-meal blood glucose after a standardized rice challenge.” 

Moreover, at 10 and 20 g per day, glucose variability improved over the two-week research, he highlights. 

“The effect was dose-dependent and time-dependent, which is exactly what you’d expect from a mechanism that works through microbiome adaptation rather than direct pharmacological action.”

Mental wellness support

Exploratory analysis in the study suggested that One.bio’s fiber may improve mental health and concentration. 

An exploratory secondary analysis on mood found improvements in irritability, depressed mood, life difficulty, worry, and concentration.Amicucci cautions that these findings warrant careful interpretation, as they were drawn from a subgroup reporting mild symptoms at baseline, without a placebo control. “What they do is validate the direction of further research.”

He details that, in this analysis, participants with mild symptoms at baseline reported improvements across domains, including irritability (35% reduction), depressed mood (43%), life difficulty (44%), worry (64%), and trouble concentrating (34%). 

Although these “striking signals” don’t establish causality due to the study’s design, he notes that they indicate that the targeted pathway is “active and worth rigorous investigation.” He adds that a placebo-controlled trial focused specifically on gut-brain outcomes is a clear next step.

According to Amicucci, the biological rationale for this effect is well-established. “Butyrate, produced when gut microbes ferment One.bio 01 oat fiber, has been shown in preclinical work to stimulate the production of brain-derived neurotrophic factor (BDNF), a protein that supports neuronal health and growth.” 

“Butyrate also reduces systemic inflammation, and inflammation is increasingly understood as an upstream driver of mood disruption, brain fog, and cognitive fatigue,” he adds. “The gut-brain axis is a documented bidirectional signaling pathway, and the microbes living in the large intestine have a measurable influence on how the brain functions.”

Fiber tolerability

The study finds that the fiber was “exceptionally well tolerated across all doses,” with groups consuming 5 or 10 g experiencing significant reductions in abdominal symptoms and a decrease in constipation compared to baseline. 

Amicucci says this means the fiber is gentle at low servings and beneficial at higher ones, highlighting that this level of tolerability marks the difference between a fiber that has a beneficial effect and those that can be used in products, as most commodity fibers, such as inulin and polydextrose, have a practical ceiling. 

The study finds that the fiber was well tolerated across all doses, with reduced abdominal symptoms for those consuming 5 or 10 g.“At the servings needed to deliver a real benefit, they produce gastrointestinal discomfort that makes daily use unworkable for most people. That ceiling is the reason fiber supplementation has such high discontinuation rates.”

However, Amicucci underscores that One.bio 01 oat fiber “has no such ceiling.” The study used Total Gastrointestinal Symptom Rating Scale scores — a measure of digestive symptoms including bloating, abdominal pain, constipation, and diarrhea — which he stresses did not increase at any serving level, including 20 g/day. 

“For manufacturers, this matters enormously,” he adds. “Formulating at the serving that delivers a glucose benefit, 10 to 20 g per day, is now feasible without the tolerability tradeoff that has constrained category growth.” 

In addition, he says that the One.bio 01 fiber is flavorless, odorless, colorless, and water-soluble, which means it can be added to beverages, foods, and supplements without altering sensory properties. 

Filling the fiber gap

Amicucci highlights One.bio 01 ingredient’s potential in filling the fiber gap. He says that in the US, average fiber consumption amounts to 15 g a day, even though the US Department of Agriculture recommends 25–38 g and emerging research even suggests an optimal intake of around 50 g. 

“The gap between what people eat and what the gut microbiome needs to function is enormous, and it is a food-system failure,” he stresses. “Modern food processing removed the fiber that nature packaged with sugar and starch. One.bio’s work is about restoring what was taken out — at the molecular level, in forms people can actually eat, backed by science that holds up to peer review.”

According to Amicucci, One.bio 01 oat fiber’s tolerability and organoleptic profile make it accessible across a wide range of consumer groups and foods and beverages, without sensory compromise. He says this “removes the behavioral barrier” that historically prevented fiber supplementation from scaling. 

He highlights people with insufficient fiber intake as key target consumers for the ingredient, which he notes amounts to 95% of adults in the US. “Even participants with minimal gastrointestinal symptoms at baseline saw improvement, which suggests the benefit isn’t limited to those with diagnosed digestive conditions.”

“The glucose findings are most relevant for the large and growing population managing blood sugar within a healthy range who want to stay there — people with prediabetes, those with a family history of metabolic disease, or anyone whose diet has drifted toward the low-fiber, high-refined-carbohydrate pattern that now describes most of the industrialized world.”

Amicucci says that the One.bio 01 fiber can be added to beverages, foods, and supplements without altering sensory properties.Moreover, Amicucci says that the study’s exploratory mental health signals point toward people experiencing mild anxiety, low mood, or cognitive fatigue — a population that is “enormous and underserved” by existing nutritional interventions.

What’s next?

The researchers are preparing a follow-up publication on microbiome composition and SCFA data from the same study population, says Amicucci, which aims to explain the mechanisms behind the glucose and gastrointestinal outcomes. 

“We are kicking off our next clinical trial later this summer that takes a deeper look at these metabolic benefits with a larger population and over a longer duration,” he adds. “This next study will be double-blind and placebo-controlled.” 

On the commercial side, he says that One.bio is working with supplement and packaged food companies to integrate the fiber into products their consumers already use. Currently, consumer access runs through One.bio’s brand of ready-to-drink products, GoodVice. 

Moreover, Amicucci highlights developments on the company’s innovation platform, which it used to build its fiber ingredient. 

“The same approach that produced One.bio 01 oat fiber is already pointed at the next generation of fibers. The Glycopedia, One.bio’s proprietary database linking fiber molecular structure to microbiome function and downstream health outcomes, has cataloged more than 4,000 natural fiber sources and has over 100 candidate fibers in biological screening.”

He concludes that the company’s goal with this platform is to develop a growing portfolio of structure-specific fibers, each validated for a defined health outcome and entering the market backed by peer-reviewed data.