They may be super sweet, but “mikan” Japanese mandarin oranges can prevent diabetes and other lifestyle-related diseases, a Japanese research team has found.
The higher the levels of beta-cryptoxanthin--a substance found in mikans--people have in their blood, the lower the risk of diabetes, non-alcoholic liver dysfunction and other disorders they have. That was the key finding by the scientists from the National Agriculture and Food Research Organization (NARO) and Hamamatsu University School of Medicine.
“It is widely believed that fruits contain high levels of sugar and so increase the risk of diabetes,” said Minoru Sugiura, a senior researcher at the NARO. “But our findings revealed they are a preventive factor for the disease rather than a risk factor.”
The researchers conducted a nutrition epidemiological survey and studied a total of 1,073 male and female residents of the Mikkabi-cho district of Hamamatsu, which is noted for its production of "unshu-mikan" oranges.
The test subjects, ranging in age from 30 to 70, were recruited at regular health checkups in the region.
Their health conditions and blood concentration of beta-cryptoxanthin, an orange-colored pigment contained in mikans, were examined over the 10 years from 2003. The researchers then statistically analyzed the association between human health and the substance.
The results showed people with higher blood levels of beta-cryptoxanthin, who eat three to four mikans a day, were 57 percent less likely to develop diabetes compared with people who consume less than one mikan daily.
Those who eat three to four mikans a day also have a 49-percent lower risk of non-alcoholic liver dysfunction and a 33-percent lower risk of abnormal lipid metabolism as well.
When beta-cryptoxanthin was administered to mice, the researchers found the substance decreased hepatic inflammation and promoted energy consumption by fat cells.