South Korea Fiber Program Cuts Blood Sugar in 6 Weeks

A study from South Korea suggests that combining a specific dietary fiber supplement with nutritional coaching and continuous glucose monitoring may meaningfully improve blood sugar control in adults at risk for type 2 diabetes — and it only took six weeks to see results.

What Researchers Did

Scientists at Maeil Health Nutrition Co., Ltd. in Pyeongtaek, South Korea, enrolled 29 adults between the ages of 20 and 55 who had fasting plasma glucose (FPG) levels of 100 mg/dL or higher — a threshold that places individuals in the prediabetes or early diabetes range according to both Korean and American standards. About 80% of participants were male, and roughly 75% were classified as overweight or obese.

For six weeks, participants followed a three-part program:

• Partially hydrolyzed guar gum (PHGG), sold as Sunfiber®, at 12.5 grams per day
• Weekly nutritional coaching sessions
• Continuous glucose monitoring (CGM) devices to track real-time blood sugar

What They Found

Among the 17 participants who closely followed all program requirements, the results were statistically significant. Fasting plasma glucose dropped from 113.06 mg/dL to 106.24 mg/dL (p < 0.05), and HbA1c fell from 6.08% to 5.87% (p < 0.05). All 29 participants showed improvements in nutritional quality scores, and approximately 82% reported positive changes in gut health, including digestion and bowel regularity.

What Is Partially Hydrolyzed Guar Gum?

PHGG is a soluble dietary fiber derived from guar beans. Unlike some fiber supplements, it dissolves easily in water without thickening, making it relatively simple to add to food or beverages. It works by slowing glucose absorption in the gut, which helps blunt blood sugar spikes after meals. Sunfiber® is the commercial brand used in this study and is available in the United States as well.

How This Compares to US Guidelines

The American Diabetes Association (ADA) recommends that adults with prediabetes — defined as FPG between 100–125 mg/dL or HbA1c between 5.7%–6.4% — pursue structured lifestyle interventions including dietary changes, increased physical activity, and weight management. The South Korean program mirrors this philosophy but adds a clinically studied fiber supplement and real-time CGM feedback, tools that are increasingly discussed but not yet universally included in standard US prediabetes care plans.

Why This Matters for US Patients

More than 96 million American adults have prediabetes, yet the majority are unaware of their status. This South Korean research is valuable because it tests a low-barrier, multi-tool approach that patients can realistically follow. The fiber supplement used (Sunfiber®) is already sold in the US, CGM devices are now available without a prescription, and nutritional coaching is increasingly covered by insurance under diabetes prevention programs. The study suggests that combining these three accessible tools — even briefly — may move the needle on blood sugar before a prediabetes diagnosis progresses to type 2 diabetes.

It is important to note this was a small pilot study with no control group, so results should be interpreted cautiously. Larger randomized trials are needed to confirm these findings.

The Bottom Line

A six-week South Korean program combining a soluble fiber supplement, dietary coaching, and glucose monitoring produced measurable blood sugar improvements in adults with elevated fasting glucose. For US patients in the prediabetes range, this research points to a practical, combinable strategy worth discussing with your healthcare provider.

Source: Park, Jeong, Hong. "Effects of a multi-component program based on partially hydrolyzed guar gum (Sunfiber®) on glycemic control in South Korea: a single-arm, pre-post comparison pilot clinical trial." Korean Journal of Community Nutrition, 2025. DOI: 10.5720/kjcn.2024.00276. PMID: 41030495.