Patent applied for research on "Kuga yam (Ryukyu yam)", a native Okinawan yam Patent Applied for Research on Activation of Mucosal Immunity ～New Hopes for Influenza and Pollen Season

2025.02.21 08:00

株式会社沖縄テレビ開発

Okinawa Television Development Corporation (Location: Naha City, Okinawa Prefecture; President: Naoya Ota), which conducts research, development, and sales of "LeQ'om," a product utilizing the Okinawa native yam "Kuga yam" (also known as Ryukyu yam), has confirmed the potential of kuga yam to activate mucosal immunity and prevent upper respiratory tract infections in a new human study conducted by Professor Motoyuki Iemitsu of Ritsumeikan University's Sports Health Science Department. (Location: Naha, Okinawa, Japan; President: Naoya Ota), which conducts research, development, and marketing of "LeQ'om," has confirmed the possibility of activating mucosal immunity and preventing upper respiratory tract infections in a new human study conducted by Professor Motoyuki Iemitsu of the Department of Sports Health Sciences, Ritsumeikan University.

Details of "LeQ'om": https://www.leqom.com/

Research Summary

Professor Motoyuki Iemitsu of Ritsumeikan University's College of Sports and Health Science has been studying the issue of upper respiratory tract infections (colds and other symptoms) caused by a decline in oral immune function due to hard training, which is a common cause of poor conditioning in athletes and exercisers. The study was conducted in 2024 using a rare native Okinawan yam, "Kuga Yam (also known as Ryukyu Yam)".

Research Results

In the study, the researchers conducted a randomized, double-blind, crossover comparison study in which participants consumed a tablet of kuga yam food or a placebo (sham) tablet for two weeks, performed transient exercise before and after the intake, and observed changes in the secretion capacity of markers such as secreted immunoglobulin A (S-IgA) in the oral mucosa before and after the exercise. The study was conducted before and after the transient exercise. S-IgA is one of the immune antibodies secreted on the surface of mucous membranes including mouth, nose, and throat. S-IgA is one of the immune antibodies secreted on the surface of mucous membranes, including the mouth, nose, and throat, and plays a role in trapping and preventing viruses and pollen that try to invade the upper respiratory tract (nose and throat) in particular. The results of the study showed that S-IgA secretion was significantly elevated at baseline before and after exercise after 2 weeks of consumption of kuga yam food, indicating that kuga yam is expected to stimulate mucosal immunity.

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Application of Research Results

In addition to the prevention of poor conditioning caused by a temporary decline in oral immune function after daily training, we will continue our research to meet the needs of people who want to stay healthy by enhancing their immunity, such as for the general public and the elderly due to fatigue and aging.

What is Ryukyu yam?

Kuga yam, also known as Ryukyu yam, is a botanically classified species of yam in the family araceae, which is related to yam and yam. It is a rare species, with Okinawa Prefecture being the northern limit of production in Japan due to its low susceptibility to cold. It is reported to contain higher levels of diosgenin, a functional component derived from yams, than other domestic and foreign yams, and in recent years, research has been conducted on its effects on muscles when combined with exercise, and on physiological activities related to sugar and fat metabolism, among others.

栽培中のクーガ芋の様子

Cultivated kuga yams in cultivation

収穫したクーガ芋

Harvested kuga yams

クーガ芋活用商品のレキオム

LeQ'om, a product using kuga yams

Research System and Future Prospects

In addition to the kuga sweet potato supplements currently being sold under the LeQ'om brand, Okinawa Television Development Corporation plans to launch a powder-type product and an amazake smoothie made from kuga yams by 2025. In addition, research is underway for sales in North America, and along with the expansion of domestic and overseas sales channels, the company plans to offer kuga yams as a local food ingredient to resort hotels and restaurants in the prefecture, and to propose health care programs in conjunction with exercise in collaboration with local governments, in order to promote kuga yams in the sports and health industry and the tourism industry. We are planning industrial development of kuga yams in cooperation with the sports and health industry and the tourism industry.

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