Natural Living Newsletter

Mulberry Leaf Extract in Type 2 Diabetes

Introduction

The mulberry plant (Morus alba) is probably best known as the food for silkworms, but it has also been highly regarded in traditional Chinese and Japanese medicine. It has been shown to possess significant blood sugar lowering effects in animal studies. Recently, human studies have confirmed its benefits in both preventing and treating type 2 diabetes.

Mulberry contains an important compound known as moranoline (also known as 1-deoxynojirimycin) that inhibits an enzyme in the intestinal tract (alpha-glucosidase) that is involved in the digestion of carbohydrates. Specifically, moranoline has been shown to prevent complex carbohydrates, starches, maltose and sucrose (white sugar) from breaking down into highly absorbable glucose molecules.

Mulberry extract reduces the glycemic effect of sugar

Mulberry extract appears to exert considerably more benefits than just inhibiting the breakdown and absorption of sugars. In one human study, healthy volunteers received 0.8 and 1.2 g of a mulberry extract standardized to contain 1.5% moranoline (corresponding to 12 and 18 mg of moranaline, respectively) prior to receiving a 50 g dosage of sucrose.1 Before and 30-180 minutes after the mulberry/sucrose administration, plasma glucose and insulin levels were determined. The results indicated that while the mulberry extract reduced peak glucose levels by only 10%, peak insulin levels were reduced by over 30% indicating increased insulin action – a key goal in the treatment of insulin resistance, pre-diabetes, and type 2 diabetes. At 60 minutes, blood glucose and insulin levels were both more than 50% in the group getting the 1.2 g dose of mulberry extract supplying 18 mg of moranoline. Again, this effect indicates significantly enhanced insulin action.

Mulberry extract in the treatment of type 2 diabetes

Mulberry has been studied in the treatment of type 2 diabetes and the results are excellent. In fact, in one of these studies the results are superior to standard drug therapy.2 In the study, researchers compared mulberry’s blood sugar lowering actions to the oral diabetes drug glyburide which is also known as glibenclamide and Micronase. Patients were given either mulberry dried leaves at a dose of 3 g/day or one tablet of glyburide (5 mg/day) for four weeks. The results clearly show that the fasting blood glucose concentrations were significantly lowered with mulberry therapy, suggesting mulberry therapy is effective in controlling diabetes. Compared to glyburide treatment, mulberry therapy significantly reduced fasting blood glucose concentrations of diabetic patients by 27%. However, in those subjects getting glyburide there was no significant differences observed between pre- and post-treatment. Mulberry extract was also superior to the approved drug in its ability to decrease hemoglobin A1C – a marker of long-term blood sugar control.

While gliburide subjects enjoyed some minimal improvements in their blood lipid profile, the changes were not statistically significant, except for triglycerides, which fell by 10%. Mulberry patients, on the other hand, experienced striking improvements across all lipid parameters, including a dramatic drop in harmful LDL by 23% along with an 18% increase in highly desirable HDL.

The research team also measured changes in lipid peroxidation in plasma, urine, and red blood cell membranes. Lipid peroxidation occurs when lipids are oxidized in the body, rendering them damaged and yet more harmful. One of the goals of antioxidant therapy is to prevent lipid peroxidation from occurring. In this study, plasma and urinary lipid peroxidation dropped significantly in both groups, but the effect was stronger among mulberry patients. Only mulberry significantly improved lipid peroxidation and decreased cholesterol in red blood cell membranes. These results indicate that mulberry not only reduces harmful lipids and apparently improves sensitivity to glucose, but also possesses beneficial antioxidant properties.

Table 1 - Influence of mulberry and glyburide treatments on blood glucose, glycosylated hemoglobin and serum lipids of the patients with type 2 diabetes

	Glyburide			Mulberry
Parameter	Before	After	Change (%)	Before	After	Change (%)
Fasting blood glucose (mg/dl)	154.4	141.8	-8	152.7	110.5	-27%
A1C (%)	12.5	12.4	0	12.5	11.2	-10
Cholesterol (mg/dl)	190	182	-4	193.7	170.3	-12
LDL-cholesterol (mg/dl)	102.5	95.5	-7	102.1	78.7	-23
HDL-cholesterol (mg/dl)	49.8	51.3	3	50.1	59.2	18
Triglycerides (mg/dl)	199.5	180	-10	200.4	168	-16
Free fatty acids (pmol/dl)	589.8	580	-2	590.1	520	-12

Practical information

Mulberry leaf extract is available in a 30:1 concentrate standardized to contain 2% moranoline content. The recommended dosage is 100 mg two to three times daily. Mulberry leaf extract has no known toxicity, but as the effects during pregnancy and lactation have not been sufficiently evaluated, it is not recommended for use during these times unless directed to do so by a physician. Since mulberry leaf extract improves blood sugar control, individuals on oral hypoglycemic drugs for type 2 diabetes will need to monitor blood sugar levels and work with their physician to adjust drug dosage as needed.