Banaba extract is a dietary supplement that is believed to help maintain normal blood sugar and insulin levels. It is also used as an aid to weight loss. The extract comes from the leaves of the Banaba tree, which is native to the Philippines, Australia and Southeast Asia. Banaba extract is generally sold in capsule form and is usually easy to find at most health food stores. In some countries such as Japan, it is sometimes served in tea.
The leaves of the banaba tree contain corosolic acid, which is believed to work much in the same way as insulin. It has a lowering effect on glucose levels, which is considered an important factor in weight loss and diabetes. In a process called glycolysis, it breaks down carbohydrates and turns them into energy. In studies conducted on diabetic rodents, banaba extract was shown to normalize insulin levels. In addition to corosolic acid, banaba extract is said to contain other phytochemicals such as stroemin, flosin B, and reginin A, all of which are believed to help lower the levels of glucose in the bloodstream.
Clinical studies involving people suffering from type 2 diabetes demonstrate that banaba extract may be able to decrease glucose levels by as much as 30%. This is critical to weight loss, because elevated insulin and blood sugar levels are believed to be linked to appetite. This elevation can cause binge eating and carbohydrate cravings. Eating large amounts of foods that are high in carbohydrates is believed to be directly linked to weight gain and type 2 diabetes.
In the late 1990s, the Japanese conducted studies to determine the effect of banaba extract on obese mice. The mice were given corosolic acid, derived from banaba extract. Results from this study were published in 1999 and seemed to show that the mice given the extract not only achieved weight loss, but their levels of triglycerides were also reduced. High triglycerides levels can lead to serious illnesses such as heart disease and high blood pressure.
There are no known side effects associated with banaba extract. People who are taking insulin should probably consult with their physician before taking other substances that may lower blood sugar. The combined ingredients could cause levels to drop dangerously low. It is also not recommended for pregnant women or women who might be breast-feeding, as studies regarding effects on lactation and fetal development are not well-documented.