Bitter melon extract may benefit glucose control Original paper

    In this randomized controlled study in adults with prediabetes, supplementing with bitter melon extract somewhat improved glucose tolerance but didn’t affect insulin resistance or insulin sensitivity.

    This Study Summary was published on August 10, 2023.

    Quick Summary

    In this randomized controlled study in adults with prediabetes, supplementing with bitter melon extract somewhat improved glucose tolerance but didn’t affect insulin resistance or insulin sensitivity.

    What was studied?

    The effect of bitter melon extract on glucose control in people with prediabetes.

    Who was studied?

    65 Korean adults with prediabetes (average age of 55; 26 men and 39 women).

    Prediabetes was defined as having a fasting blood glucose level of 100–125 mg/dL or an HbA1c of 5.6%–6.4%.

    How was it studied?

    In this randomized controlled study, the participants received bitter melon extract (2.4 grams) or a placebo daily for 12 weeks.

    The primary outcomes were fasting blood glucose, HbA1c, insulin, glucagon, C-peptide, and blood lipids (total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides).

    Glucose measures (i.e., glucose, insulin, C-peptide, and glucagon) were assessed at baseline and at 30, 60, and 120 minutes after an oral glucose tolerance test (OGTT). Insulin resistance (HOMA-IR), insulin secretion (HOMA-β) and insulin sensitivity (Matsuda index) were derived from the OGTT.

    What were the results?

    When comparing the OGTT results from baseline and 12 weeks, blood glucose was lower at 30 minutes (−10.3 mg/dL) in the bitter melon extract group. Blood glucose was lower at 120 minutes during the OGTT in the bitter melon group (−10.03 mg/dL vs. baseline) compared to the placebo group (+12.5 mg/dL vs. baseline).

    Furthermore, glucagon levels were lower during the OGTT at 120 minutes (−75.5 pg/mL) in the bitter melon extract group compared to baseline and when compared to the placebo group.

    Anything else I need to know?

    It may not be surprising that fasting blood glucose levels didn’t change after 12 weeks of supplementing with bitter melon extract, considering that the participants did not have diabetes and had baseline fasting glucose levels of 101 mg/dL and 107 mg/dL in the bitter melon and placebo groups, respectively, which may not be high enough for notable improvements to occur.

    Dizziness was reported in 8 participants in the bitter melon extract group (and none in the placebo group), indicating that this is a side effect that may deserve attention; however, the mechanisms for this effect are unclear but could be related to hypoglycemia.

    This Study Summary was published on August 10, 2023.