Overweight volunteers supplemented with licorice flavonoid oil lost more weight and body fat, compared to people receiving the placebo, according to results of a randomized, double-blind, placebo-controlled study published in Obesity Research & Clinical Practice.
Additionally, the fat losses were not associated with a reduction in food intake, report the researchers from Kaneka, Tokyo's Kaiyuu Clinic, Haradoi Hospital, and Kiryu University.
If the results can be repeated in further studies, it could see the licorice oil establish itself in the burgeoning weight management category, estimated to be worth about US$0.93bn (€0.73bn) in Europe in 2005 and $3.93bn in the US, indicating that call to slim down or face the health consequences is being heeded by a slice of the overweight population at least, according to Euromonitor International.
Lead author Yuji Tominaga from Kaneka and co-workers recruited 56 overweight men and 28 overweight women aged between 40 and 60 to take part in the study. The volunteers were randomly assigned to one of four groups. The first group received a daily placebo, while the other three groups received Kaneka’s Glavonoid ingredient at doses of 300, 600, or 900 mg per day.
After eight weeks of supplementation, the researchers report that, while the energy intake was similar in all four groups, volunteers who consumed the licorice flavonoid oil experienced significant reductions in total body fat mass. Indeed, people receiving the 300 mg dose lost 0.92 kg of body fat, while those consuming the 900 mg dose lost 0.89 kg.
Furthermore, the highest dose was associated with a significant 9.35 cm3 reduction in visceral fat area, a 0.25 kg/m2 decrease in BMI, and a 11 mg per deciliter reduction in LDL-cholesterol levels.
Importantly, the researchers also state that no significant adverse effects were observed throughout the study.
Commenting on the mechanism, the Japanese scientists note that results from previous studies indicated that licorice flavonoid oil may down-regulate the genes involved in fatty acid synthesis, while also up-regulating genes for enzymes linked to fatty acid oxidation.
“Thus, we presume that licorice flavonoid oil increases energy expenditure by enhancing beta-oxidation and inhibits lipogenesis resulting in reduction in body fat and body weight,” wrote Tominaga and his co-workers.
“However, further studies are necessary to clarify the cause of body fat reduction and to examine the licorice flavonoid oil -mediated metabolic changes in adipose tissue and muscle.”
Take home message
“The present study demonstrated that administration of licorice flavonoid oil safely reduced body weight in overweight subjects by reducing total body fat,” wrote the researchers.
“Supplementation with licorice flavonoid oil (at least 300 mg/day, preferably 900 mg/day) may contribute to prevent or ameliorate obesity and probably to prevent obesity-induced metabolic syndrome, when combined with life-style modifications including moderate calorie restriction and moderate exercise,” they concluded.
Source: Obesity Research & Clinical Practice
August 2009, Volume 3, Issue 3, Pages 169-178
“Licorice flavonoid oil reduces total body fat and visceral fat in overweight subjects: A randomized, double-blind, placebo-controlled study”
Authors: Y. Tominaga, K. Nakagawa, T. Mae, M. Kitano, S. Yokota, T. Arai, H. Ikematsu, S. Inoue