Green jackfruit flour a better carb for people with diabetes

Jackfruit flour may be an ideal substitute for rice or wheat flour to improve glucose control in patients with type 2 diabetes mellitus (T2DM), according to a study.

“Green jackfruit is a good source of fibre, has fewer calories, and in flour form makes it easy to include in a variety of daily food like roti, porridge, or pancakes as part of medical nutrition therapy for T2DM without changing eating habits,” the investigators said.

“In the present study, the jackfruit flour had 25 percent lower calories, 33 percent lower net carbohydrates, and 57 percent more fibre in comparison to placebo flour,” they pointed out.

Replacing an equal volume of rice or wheat flour in daily meals with the flour yielded meaningful reductions in glycosylated haemoglobin (HbA1c), fasting plasma glucose (FPG), and postprandial plasma glucose (PPG) levels, the investigators added.

A total of 40 adult T2DM patients (mean age 46 years) receiving glucose-lowering drugs had been randomized to consume either jackfruit flour 30 g/day (n=20) or placebo flour (n=20) as a substitute for an equal volume of rice or wheat flour. They did this for breakfast and dinner every day for 12 weeks.

Green jackfruit flour was prepared from dehydrated, mature, unripe jackfruits. Every 30 grams of the flour provided calorie of 108 kcal, net carbohydrate of 20 g, and dietary and soluble fibre content of 4 g and 1 g, respectively.

At week 12, the primary endpoint of HbA1c decreased in the jackfruit group but increased in the placebo group (mean, −2.73 mmol/mol [−0.25 percent] vs 0.22 mmol/mol [0.02 percent]; p=0.006). [Nutr Diabetes 2021;11:18]

Consumption of jackfruit flour also led to greater reductions in FPG (−1.63 vs −0.89 mmol/L; p=0.043) and PPG (−2.03 vs −0.47 mmol/L; p=0.001). Continuous glucose monitoring (CGM) data showed decreasing mean blood glucose levels over 7 days of consumption, as did the placebo group, which the investigators attributed to the combined placebo effect of CGM and the intervention.

“In addition, these results [on CGM] may be inconclusive as two of the five patients (40 percent dropout) … from the placebo group were excluded from the analysis,” they added.

Belonging to the mulberry family, jackfruit (Artocarpus heterophyllus) is mostly grown in the tropical regions of the world, especially in the Western Ghats of India. The green or unripe fruit is used as a vegetable. When ripe, the fruit is very sweet and rich in sugars, which raises concern among patients with diabetes, the investigators noted.

The proanthocyanidin and flavonoids phytochemical compounds present in jackfruit are said to be responsible for the fruit’s glucose-lowering effect. This benefit has indeed been demonstrated in several in vitro and in vivo studies, potentially as a result of inhibition of lipid peroxide formation. [J Med Biol Eng 2015;4:318-323; Am J Food Technol 2012;7:43-49; Adv Pharm Bull 2018;8:141-147; Int J Ayurveda Pharma Res 2017;5:20-25]  

Aside from the mentioned compounds, jackfruit also contains carotenoids, volatile acids, sterols, and tannins. [Chem Biodivers 2007;4:2166-2171; J Sci Food Agric 2004;85:186-190; Postharvest Biol Technol 2006;40:279-286]

“With the efficacy data and adherence to intervention known from this study, a multicentric, multicountry powered study with a larger population, for longer duration, and higher HbA1c may be needed to further confirm clinical significance and generalize [the] outcomes to a wider population,” according to the investigators.