Mandarijnen tegen overgewicht en hartproblemen*
Uit een Canadese studie, weliswaar met muizen blijkt dat de bioactieve stof
uit de groep flavonen te weten nobiletine bescherming kan bieden tegen overgewicht,
diabetes type-2 en aderverkalking. Nobiletine wordt gevonden in
mandarijnen en hun schil. In de studie kreeg de ene groep muizen een normaal westers dieet en de andere groep muizen hetzelfde dieet maar dan aangevuld met nobiletine. De muizen met het westers dieet bleken overgewicht te krijgen, hoge cholesterol waarden, hoge triglyceriden waarden, hoge glucose, insuline waarden en een vette lever. De muizen in de groep met de aanvulling van nobiletine kregen geen overgewicht en hadden normale waarden cholesterol, triglyceriden, insuline en glucose. Deze waren ook gevoeliger voor insuline en hadden geen tekenen van een vette lever. Na langere tijd bleek de muizen in deze laatste groep ook beschermd te zijn tegen aderverkalking. In een eerdere
studie van dezelfde onderzoekers vond men dat de bioactieve stof naringenine ook vergelijkbare resultaten gaf doch zo zeggen de onderzoekers nobiletine heeft wel 10x meer effect.
Substance in Tangerines Fights Obesity and Protects Against Heart Disease, Research Suggests
New research from The University of Western Ontario has discovered a substance in tangerines not only helps to prevent obesity, but also offers protection against type 2 diabetes, and even atherosclerosis, the underlying disease responsible for most heart attacks and strokes.
Murray Huff, a vascular biology scientist at the Schulich School of Medicine & Dentistry, along with Erin Mulvihill, a PhD student, studied the effects of a flavonoid in tangerines called Nobiletin. Their research is published in the journal Diabetes.
In a model of metabolic syndrome developed by the Huff laboratory at the Robarts Research Institute, mice were fed a "western" diet high in fats and simple sugars. One group became obese and showed all the signs associated with metabolic syndrome: elevated cholesterol and triglycerides, high blood levels of insulin and glucose, and a fatty liver. These metabolic abnormalities greatly increase the risk of cardiovascular disease and type 2 diabetes.
The second group of mice, fed the exact same diet but with Nobiletin added, experienced no elevation in their levels of cholesterol, triglycerides, insulin or glucose, and gained weight normally. Mice became much more sensitive to the effects of insulin. Nobiletin was shown to prevent the buildup of fat in the liver by stimulating the expression of genes involved in burning excess fat, and inhibiting the genes responsible for manufacturing fat.
"The Nobiletin-treated mice were basically protected from obesity," says Huff, the Director of the Vascular Biology Research Group at Robarts. "And in longer-term studies, Nobiletin also protected these animals from atherosclerosis, the buildup of plaque in arteries, which can lead to a heart attack or stroke. This study really paves the way for future studies to see if this is a suitable treatment for metabolic syndrome and related conditions in people."
Huff's research has focused on the pharmacological properties of naturally-occurring bioactive molecules. Two years ago, his research drew international attention when he discovered a flavonoid in grapefruit called Naringenin offered similar protection against obesity and other signs of metabolic syndrome. Huff says "What's really interesting to us is that Nobiletin is ten times more potent in its protective effects compared to Naringenin, and this time, we've also shown that Nobiletin has the ability to protect against atherosclerosis."
The research was funded primarily by the Heart and Stroke Foundation of Ontario, with additional grant support from the Pfizer Canada Cardiovascular Research Program. (Juni 2011)
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