Efficacy of green jackfruit flour as a medical nutrition therapy replacing rice or wheat in patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled study

T2DM is a chronic metabolic disorder with rising prevalence in India, projected to affect ~100 million people by 2030. Medical nutrition therapy (MNT) is a key component of glycemic management alongside medications. Jackfruit (Artocarpus heterophyllus) is rich in fiber, vitamins, and minerals; concerns about its suitability in diabetes stem from the sweetness of ripe fruit. Preclinical and limited clinical evidence suggest antidiabetic properties of jackfruit components, potentially via antioxidant and insulinotropic pathways. An assessment in Kerala suggested reduced antidiabetic medication demand during jackfruit season. No randomized controlled trials had evaluated green jackfruit flour for glycemic control in T2DM. This study aimed to test whether replacing an equal volume of rice or wheat flour in daily meals with Jackfruit365 green jackfruit flour improves glycemic control in adults with T2DM.

Jackfruit contains carotenoids, proanthocyanidins, flavonoids, volatile acids, sterols, and tannins. Antidiabetic effects have been reported in vitro and in vivo, attributed in part to high proanthocyanidin and flavonoid content and inhibition of lipid peroxidation. Animal studies show glucose-lowering effects of jackfruit seed, leaves, and fractions, with potential mechanisms including enhanced insulin secretion. Limited human data, including a single-blinded study of jackfruit leaf decoction, demonstrated reductions in FPG and PPG. Dietary guidance (ADA 2019) emphasizes lower calories/carbohydrates and higher fiber intake to improve glycemic control; higher dietary fiber is associated with lower HbA1c. Prior assessment in Kerala suggested green jackfruit as an alternative to rice may reduce medication demand.

Design: Randomized, double-blind (participants and investigator), placebo-controlled, single-center trial (CTRI/2019/05/019417) at Rajiv Gandhi Institute of Medical Sciences, Srikakulam, India (May 2019–Feb 2020). Ethics approval obtained; informed consent provided. Randomization: 1:1 using computer-generated sequence with sequentially numbered, sealed, opaque envelopes. Intervention: Group A received Jackfruit365 green jackfruit flour 30 g/day (15 g added to breakfast and 15 g to dinner) for 12 weeks; Group B received placebo flour equal in volume (rice flour for rice-based meals and wheat flour for wheat-based meals) matching pre-intervention diet. Both groups added study flour first, then regular batter/flour to usual portion size, achieving equal volume replacement of rice or wheat flour. A subset of five patients per group underwent masked CGM for 14 days (7 days pre-randomization and 7 days post-randomization) with FreeStyle Libre Pro. Nutritional composition (per 30 g): jackfruit flour 108 kcal, 20 g net carbohydrates, 4 g dietary fiber, 1 g soluble fiber; placebo flour equal volume 146 kcal, 30 g net carbohydrates, 2.54 g dietary fiber, 0 g soluble fiber. Participants: Adults 18–60 years, T2DM >1 year, on oral hypoglycemic agents (mono/polytherapy), HbA1c <8% at screening; concomitant medications allowed. Exclusions: pregnancy; insulin use; severe/chronic hepatic or renal disease; active malignancy; significant cardiovascular event within 12 weeks; major diabetic complications (ketoacidosis, nephropathy, neuropathy, retinopathy, diabetic wounds); chronic contagious infections (active TB, hepatitis B/C, HIV); metabolic or GI diseases affecting nutrient absorption/metabolism/excretion (excluding diabetes); use of investigational drugs within 1 month or participation in another trial. Assessments: Baseline and week 12 HbA1c (primary); secondary endpoints included FPG, PPG, body weight, BMI, lipid profile (cholesterol, HDL, LDL, triglycerides), and CGM metrics in the subset. Statistics: SAS v9.4; qualitative data as counts/percentages; quantitative data as mean (SD). Between-group comparisons via independent t-test; p<0.05 significant. Maximum participation 13 weeks (1-week screening + 12-week treatment). No changes to oral hypoglycemic doses were reported; hypoglycemia events were monitored.

Participants: 42 screened; 40 randomized (Group A n=20; Group B n=20). One placebo patient lost to follow-up (n=19 for some analyses). Baseline characteristics were comparable (mean age ~46 years; majority male). Primary endpoint: HbA1c decreased in Group A from 55.57 mmol/mol (7.23%) to 52.84 mmol/mol (6.98%), mean change −2.73 mmol/mol (−0.25%). In Group B, HbA1c changed from 55.88 mmol/mol (7.26%) to 56.11 mmol/mol (7.28%), mean change +0.22 mmol/mol (+0.02%). Between-group difference favored jackfruit flour (p=0.006). Secondary endpoints: FPG (mg/dL) decreased from 142.85 to 113.40 in Group A (mean change −29.45 mg/dL; −1.63 mmol/L) vs 146.73 to 130.57 in Group B (−16.15 mg/dL; −0.89 mmol/L); p=0.043 for mean change and p=0.001 for week 12 levels. PPG (mg/dL) decreased from 199.35 to 162.65 in Group A (−36.70 mg/dL; −2.03 mmol/L) vs 196.52 to 187.89 in Group B (−8.63 mg/dL; −0.47 mmol/L); p=0.001. Body weight showed no significant changes in either group. Lipid profile (cholesterol, HDL, LDL, triglycerides) remained unchanged and comparable between groups. CGM subset: In jackfruit group (n=5), mean 7-day glucose decreased from 218.91 (SD 105.19) to 162.45 (SD 61.98) mg/dL (mean difference 56.46). In placebo group (evaluable n=3 due to one early probe removal and one loss to follow-up), mean decreased from 256.52 (SD 72.24) to 183.62 (SD 14.43) mg/dL (mean difference 72.49). No hypoglycemia events reported and no changes in oral hypoglycemic doses during the study.

Replacing an equal volume of rice or wheat flour with green jackfruit flour integrated into culturally typical meals significantly improved glycemic control in adults with T2DM on stable oral therapies. The observed reductions in HbA1c, FPG, and PPG align with dietary principles favoring lower caloric and carbohydrate intake and higher fiber to improve glycemia. The jackfruit flour provided fewer calories, fewer net carbohydrates, and more fiber than the placebo flour, which likely contributed to improved glycemic metrics without necessitating weight loss—relevant for many South Asians who develop T2DM at lower BMI. CGM showed short-term reductions in glucose levels after intervention initiation; however, decreases were also seen in the placebo subset, possibly reflecting behavioral/placebo effects of CGM and the intervention, and the small evaluable sample limits inference. The intervention was well tolerated, with no hypoglycemia and no medication adjustments, and was easy to incorporate into common foods, potentially supporting adherence. These findings address the research question by demonstrating that green jackfruit flour can serve as effective MNT to enhance glycemic control when replacing staple flours in daily meals.

Jackfruit365 green jackfruit flour (30 g/day) used to replace an equal volume of rice or wheat flour at breakfast and dinner for 12 weeks significantly reduced HbA1c, FPG, and PPG versus placebo in adults with T2DM, without affecting weight or lipid profile. As a fiber-rich, lower-calorie, lower-carbohydrate option, green jackfruit flour can be incorporated into routine foods (e.g., roti, porridge, pancakes) as part of MNT without major diet changes. Future research should include larger, multicenter, longer-duration trials with broader HbA1c ranges to confirm clinical significance and generalizability.

Single-center study with a small sample size and short 12-week duration. HbA1c eligibility restricted to <8% to minimize hypoglycemia risk and medication changes, potentially limiting generalizability. CGM subset was small with dropout in the placebo group, making CGM findings exploratory. The study population and dietary context may limit extrapolation to other settings.