E-News Exclusive
Bitter Melon
By Constance Brown-Riggs, MSEd, RD, CDE, CDN
Are there potential benefits for people with diabetes?
The use of complementary health approaches continues to grow worldwide. People with diabetes are 1.6 times more likely than those without diabetes to use complementary health approaches—previously known as complementary and alternative medicine. The overall prevalence of their use among people with diabetes ranges between 30% and 57%.1
One of the complementary health approaches people with diabetes use to help manage blood glucose is bitter melon (Momordica charantia). In fact, it’s used worldwide for diabetes treatment. This article will describe bitter melon, discuss the latest research on its use as a diabetes therapy, and provide strategies for nutrition professionals for counseling clients and patients who want to use it along with other medications.
What Is Bitter Melon?
Bitter melon is a fruit that belongs to the squash family and is a low-calorie nutritional powerhouse. Also known as bitter gourd, bitter melon is a perennial plant that grows in the tropical and subtropical regions of Asia, South America, East Africa, and the Caribbean. The fruit and seeds of the plant are used as food and as medicine to treat cancer, viral infections, immune disorders, and diabetes.1,2 “It’s an excellent source of vitamin K and provides vitamin C and vitamin A as well,” says Vandana Sheth, RDN, CDE, a private practitioner and national spokesperson for the Academy of Nutrition and Dietetics, based in Torrance, California. One-half cup (47 g) of fresh bitter melon contains just 10 kcal and 2 g carbohydrate.3
Mechanism of Blood Glucose Lowering
Not only is bitter melon nutrient rich, it also “has been shown to potentially help with improved blood sugars in people with type 2 diabetes,” Sheth says. Results of animal and human studies show that the whole bitter melon plant, including the fruit, leaves, and seed extract, has the ability to reduce blood glucose. Three compounds found in bitter melon—charantin, vicine, and polypeptide-p—are believed to be responsible for its hypoglycemic effects. Evidence suggests these compounds increase glucose uptake and glycogen synthesis in the liver, muscle, and adipose tissue and also improve glucose tolerance. Possible mechanisms include increased insulin secretion, tissue glucose uptake, liver muscle glycogen synthesis, glucose oxidation, and decreased hepatic gluconeogenesis.1,4
Bitter Melon’s Efficacy
In a 2014 review first published online in Nutrition Journal, researchers analyzed the available evidence for bitter melon in in-vitro studies, animal studies, and clinical trials. The researchers found conflicting results in clinical trials that examined bitter melon’s hypoglycemic effects. Direct comparison between studies was a challenge for researchers because of the diversity of subjects, differences in substrate preparation, variable end points, and poor trial design. Other problems included the short duration of the studies and small number of subjects.1
The results of the 2014 Nutrition Journal review are consistent with the Natural Medicines Comprehensive Database assessment of bitter melon for diabetes management, which found that research results so far are conflicting and inconclusive. Some studies show that bitter melon fruit, fruit juice, or extract improves glucose tolerance, reduces blood sugar levels, and lowers HbA1c in people with type 2 diabetes. However, these studies have some flaws, and other research hasn’t been positive.5
Safety
None of the studies in the 2014 Nutrition Journal review found any serious adverse events with the use of bitter melon.1 “Excessive intake of bitter melon may cause GI discomfort such as diarrhea in adults. Another concern could be a drop in blood sugars when bitter melon is consumed in excess along with blood sugar-lowering medications,” Sheth says. In addition, there have been isolated reports of hypoglycemic coma in children following the ingestion of bitter melon tea.1 “Children also may experience vomiting and diarrhea, so bitter melon isn’t recommended for that age group,” Sheth says.
Bitter melon is contraindicated in pregnancy and breast-feeding.5 “It isn’t recommended for pregnant women as it may cause bleeding and contractions,” Sheth says. Individuals with a glucose-6-phosphate dehydrogenase deficiency should avoid bitter melon, and it should be discontinued at least two weeks before surgery.5
The Natural Medicines Comprehensive Database rates bitter melon fruit as possibly safe for most people when taken by mouth in the short term. The safety of long-term use (beyond three months) is unknown. Moreover, there isn’t enough information about the safety of consuming other parts of the bitter melon.5
Bottom Line
Because of the need for further research and the inconclusive evidence regarding efficacy, dietitians can’t recommend bitter melon as a replacement therapy for insulin or other diabetes medications. Clients or patients with diabetes who’d like to try bitter melon should be counseled on safety and efficacy. Rather than recommend bitter melon supplements, dietitians should encourage patients to explore cuisines in which bitter melon is a common ingredient. “There are many traditional recipes that incorporate bitter melon within Indian cuisine,” Sheth says.
Individuals incorporating bitter melon into the diet for the first time should consult with their health care provider. They also should be encouraged to check their blood glucose levels more frequently.
— Constance Brown-Riggs, MSEd, RD, CDE, CDN, is nutrition advisor for the Dannon One Yogurt Everyday Initiative, past national spokesperson for the Academy of Nutrition and Dietetics, specializing in African American nutrition, and author of The African American Guide to Living Well With Diabetes and Eating Soulfully and Healthfully with Diabetes.
References
1. Medagama AB, Bandara R. The use of complementary and alternative medicines (CAMs) in the treatment of diabetes mellitus: is continued use safe and effective? Nutr J. 2014;13:102.
2. Bitter melon. Memorial Sloan Kettering Cancer Center website. https://www.mskcc.org/cancer-care/integrative-medicine/herbs/bitter-melon. Updated April 3, 2017. Accessed July 17, 2017.
3. Bitter melon: nutrition. Selection. Storage. Fruits & Veggies More Matters website. http://www.fruitsandveggiesmorematters.org/bitter-melon-nutrition-selection-storage. Accessed July 17, 2017.
4. Ilkay J. Bitter melon — fruit’s role in diabetes management is promising but uncertain. Today’s Dietitian. 2011;13(7):10-11.
5. Bitter melon. MedlinePlus website. https://medlineplus.gov/druginfo/natural/795.html. Updated February 13, 2015. Accessed July 17, 2017.