Curcumin, the natural pigment that gives the spice turmeric its yellow colour, could have benefits for diabetics, suggests a joint Korean-American study.
A mouse model of diabetes was used to test the effects of curcumin on various variables and significant improvements were reported for insulin resistance and glucose tolerance, report the scientists from Sunchon National University and Kyungpook National University in Korea, and Columbia University in the US.
Curcumin has increasingly come under the scientific spotlight in recent years, with studies investigating its potential benefits for reducing cholesterol levels, improving cardiovascular health, reducing the risk of Alzheimer's, and potential protection against cancer.
If results of the new study, published in the journal Molecular Nutrition & Food Research, can be repeated in humans, it may suggest potential for the spice for diabetes management or prevention.
Promising results for diabetic mice
The researchers, led by Mi-Kyung Lee, used diabetic mice, so-called db/db mice, and non-diabetic controls, named db/+. The animals were fed diets with or without added curcumin (0.02 per cent) for six weeks.
They report that the diabetic mice supplemented with curcumin experienced lower blood glucose levels, than the controls. The animals also lost less weight.
Activity of the glucokinase enzyme in the liver was higher in the diabetic mice following the curcumin-supplemented diet than in the diabetic control group. This enzyme plays a key role in the conversion of glucose into glycogen, the body's main carbohydrate stores. This would blunt the glucose rise following the meal.
The spice was also linked to reduced activity for other enzymes associated with the production of markers of cardiovascular health, such as free fatty acids, cholesterol, and triglyceride were also significantly lower following curcumin supplementation in the diabetic animals.
Importantly, no effects were observed on blood glucose, plasma insulin, and glucose regulating enzyme activities in the non-diabetic animals, stated the researchers.
"These results suggest that curcumin seemed to be a potential glucose-lowering agent and antioxidant in type 2 diabetic db/db mice, but had no affect in non-diabetic db/+ mice," they concluded.
Potential market opportunities
Significant additional research needs to be performed before anyone can contemplate recommending curcumin for diabetics, but if further studies support these preliminary positive findings, this may offer help for the estimated 19 million people affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.
In the US, there are over 20 million people with diabetes, equal to seven per cent of the population. The total costs are thought to be as much as $132 billion, with $92 billion being direct costs from medication, according to 2002 American Diabetes Association figures.
Source: Molecular Nutrition & Food Research
Published online ahead of print 8 April 2008, doi: 10.1002/mnfr.200700184
"Effect of curcumin supplementation on blood glucose, plasma insulin, and glucose homeostasis related enzyme activities in diabetic db/db mice (p NA)"
Authors: K.-I. Seo, M.-S. Choi, U.J. Jung, H.-J. Kim, J. Yeo, S.-M. Jeon, M.-K. Lee