January 1, 2008
By Syed Akbar
Hyderabad, Dec 31: Turmeric, a common kitchen ingredient, has been known for its anti-septic properties, and city nutritionists now find out that it also has the natural chemicals that are capable of preventing cataract in people suffering from diabetes.
"It is for the first time we report that turmeric, at the levels that are close to
average daily intake, can be effective in preventing diabetic cataract. One of
the important observations of this study is that both turmeric and its chemical
constituent, curcumin, delay the progression and maturation of cataract, despite elevated levels of glucose. These results thus provide a clue, for the first time, that turmeric or curcumin may act downstream to glucose-mediated changes," says a study by nutrition scientists of the National Institute of Nutrition.
Diabetes and cataract are inter-linked and cataract is more pronounced in people suffering from the disease. At present, the only treatment for cataract is surgery. It has been estimated that a delay in cataract onset by 10 years could reduce the need for cataract surgery by as much as half. The pronounced effect of turmeric may be due to other ingredients besides curcumin. The NIN study gains significance as any strategy that prevents or slows the progression of cataract has a significant health impact.
The joint study by P Suryanarayana, M Saraswat, T Mrudula and others involved feeding Wistar rats a diet including curcumin and turmeric. The turmeric and curcumin rich diet delayed the progression of diabetic cataract in rats. "Although, multiple mechanisms may contribute to these effects, the antioxidant effect of curcumin and turmeric appears to be the predominant mechanism of action," they said.
The NIN scientists selected Wistar rats and diabetes was induced by streptozotocin (a substances that damages insulin producing cells). They monitored the cataract progression due to hyperglycemia (high levels of sugar in blood). At the end of eight weeks, the animals were killed and the crystalline profile in the lens was investigated.
"Although, both curcumin and turmeric did not prevent streptozotocin-induced hyperglycemia, as assessed by blood glucose and insulin levels, slit lamp microscope observations indicated that these supplements delayed the progression and maturation of cataract," they added.
The results indicated that turmeric and curcumin are effective against the development of diabetic cataract in rats. Further, these results imply that ingredients in the study’s dietary sources, such as turmeric, may be explored
for anticataractogenic (that works against cataract formation) agents that prevent or delay the development of cataract.
