The review, published in Nutrition in the Prevention and Treatment of Abdominal Obesity, looked at possible effects of satsuma mandarin (Citrus unshiu Marc.) - a Japanese citrus species and one of the most beta-cryptoxanthin-rich foods in the world, according to the researchers.
Of mice and men
The researchers said a study of obese mice fed with the carotenoid had suggested an association with weight loss and a “significant reduction in visceral fat”. Meanwhile, a human clinical trial on mildly obese men revealed that oral intake of satsuma mandarin-derived beta-cryptoxanthin (β-CRX) decreased visceral fat, body weight, and waist circumference, the researchers said.
Further investigation revealed that β-CRX specifically effected the development, enlargement and lipid accumulation of adipocytes, or fat cells, they wrote.
The researchers said this could be due to the carotenoid's ability to down-regulate peroxisome proliferator-activated receptor gamma – a group of nuclear receptor proteins that regulate the expression of genes and play a particular role in metabolism.
“This suggests that β-CRX is effective in obesity prevention and in improving the symptoms of metabolic syndromes,” the researchers said.
The researchers added: “An important point is that these benefits are obtained without any undesirable side effects or damage to health.”
Under-exploited carotenoid?
β-CRX is a carotenoid found in human blood. The researchers said it was the only one of the six carotenoids found here – alpha-carotene, beta-carotene, lutein and zeaxanthin isomers, lycopene, and β-CRX – that had not yet been commercialised.
The researchers said that, unlike other carotenoids, β-CRX was not found in many fruits or vegetables, only in a few specific types like hot peppers, persimmons and satsuma mandarins.
A history of good health
Around one million tons of satsuma mandarin is produced in Japan annually. The researchers said the Japanese population has consumed satsuma mandarins for over 400 years, and “know empirically that the satsuma mandarin is good for their health”.
Source: Nutrition in the Prevention and Treatment of Abdominal Obesity
Published online ahead of print, doi: 10.1016/B978-0-12-407869-7.00034-9
“Chapter 34 – Beta-Cryptoxanthin, a Novel Carotenoid Derived from Satsuma Mandarin, Prevents Abdominal Obesity”
Authors: K. Takayanagi and K. Mukai