Bitter melon is traditionally used for diabetes in Asia, Africa, and South America. Bitter melon is also a medicinal plant used by Ayurvedic doctors of medicine to benefit various conditions, including diabetes. In the Philippines, bitter melon is widely used and advertised for patients who have diabetes.
Bitter melon is found in a product called Diet Rx which helps users eat less food. When less food is consumed, blood sugar does not rise as much.
Composition of bitter melon and benefit to those with diabetes
Bitter melon or bitter gourd is a vegetable that grows in the tropics. It contains substances with blood sugar managing properties such as charantin, vicine, and polypeptide-p, as well as several antioxidants which could benefit a person with diabetes. The mechanism of action, whether it is via regulation of insulin release or altered glucose metabolism and its insulin-like effect, is still being evaluated.
Antidiabetic activities of triterpenoids isolated from bitter melon associated with activation of the AMPK pathway.
Chem Biol. 2008. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Four cucurbitane glycosides, momordicosides Q, R, S, and T, and stereochemistry-established karaviloside XI, were isolated from the vegetable bitter melon (Momordica charantia). These compounds and their aglycones exhibited a number of biologic effects beneficial to diabetes and obesity.
Biter Melon Benefits in Animals
Bitter melon may be of benefit to lower plasma lipids and blood sugar in animal studies. Bitter melon may have benefit for diabetes in humans but human research is needed with bitter melon supplements to confirm or dispute these animal studies. As of 2010, most of the benefits with bitter melon extracts have been evaluated in cell culture and studies.
Bitter melon (Momordica charantia L.) inhibits adipocyte hypertrophy and down regulates lipogenic gene expression in adipose tissue of diet-induced obese rats.
Br J Nutr. 2007. Department of Health and Nutrition, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.
Bitter melon has been shown to ameliorate diet-induced obesity and insulin resistance. To examine the effect of bitter melon supplementation on cell size and lipid metabolism in adipose tissues, three groups of rats were respectively fed a high-fat diet supplemented without (HF group) or with 5 % lyophilised bitter melon powder (HFB group), or with 0.01 % thiazolidinedione (TZD) (HFT group). A group of rats fed a low-fat diet was also included as a normal control. Hyperinsulinaemia and glucose intolerance were observed in the HF group but not in HFT and HFB groups. Although the number of large adipocytes of both the HFB and HFT groups was significantly lower than that of the HF group, the adipose tissue mass, TAG content and glycerol-3-phosphate dehydrogenase activity of the HFB group were significantly lower than those of the HFT group, implying that bitter melon might reduce lipogenesis in adipose tissue. These results indicate bitter melon can reduce insulin resistance as effective as the thedrug TZD used for diabetes. Furthermore, bitter melon can suppress the visceral fat accumulation and inhibit adipocyte hypertrophy, which may be associated with markedly down regulated expressions of lipogenic genes in the adipose.
Lipid lowering effects of Bitter Melon in HIV-1-protease inhibitor-treated human hepatoma cells, HepG2.
Br J Pharmacol. 20064. Nerurkar PV, Lee YK, Linden EH, Lim S, Pearson L, Nerurkar VR.
Laboratory of Metabolic Disorders and Alternative Medicine, Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, Room 415H, East-West Road, Honolulu, HI
Hyperlipidemic effects of HIV-1-protease inhibitors (PI) are associated with increased hepatic production of triglyceride (TG)-rich lipoproteins, rather than lipoprotein clearance. PI are known to increase apolipoprotein B (apoB) secretion, apoC-III mRNA expression and decrease apoA-1 secretion. Nutritional therapy remains an important strategy to manage PI-associated hyperlipidemia. This study investigated the in vitro efficacy of Asian vegetable, bitter melon to ameliorate PI-associated apoB and lipid abnormalities in HepG2 cells. Our study demonstrates that bitter melon juice significantly reduced apoB secretion and apoC-III mRNA expression and normalized apoA-I expression in PI-treated HepG2 cells. Bitter melon juice also significantly reduced cellular triglyceride and microsomal TG transfer protein, suggesting that lipid bioavailability and lipidation of apoB assembly may play a role in decreased apoB secretion. Identifying molecular targets of bitter melon may offer alternative dietary strategies to decrease PI-associated hyperlipidemia and improve quality of life among HIV-1-infected patients.
Reduced adiposity in bitter melon (Momordica charantia)-fed rats is associated with increased lipid oxidative enzyme activities and uncoupling protein expression.
J Nutr. 20053. Food and Nutritional Science Program, Department of Zoology, The University of Hong Kong, Hong Kong, The People’s Republic of China.
To further explore the antiobesity effect of freeze-dried bitter melon juice, activities of mitochondrial lipid oxidative enzymes as well as the expression of uncoupling proteins and their transcription coactivator peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1alpha) were determined in diet-induced obese (DIO) rats. Rats were fed high-fat (HF) diets to induce obesity, and the effect of bitter melon was assessed at doses of 0.75, 1.0, or 1.25% (wt:wt). In a dose-response experiment, bitter melon -supplemented rats had lower energy efficiency (g weight gained/kJ consumed), visceral fat mass, serum glucose, and insulin resistance index, but higher plasma norepinephrine than unsupplemented rats. The present results suggest that decreased adiposity in bitter melon -supplemented rats may result from lower metabolic efficiency, a consequence of increased lipid oxidation and mitochondrial uncoupling.
Bitter Melon Side Effects
As of 2010, no major bitter melon side effects have been reported in the medical literature.