Functional evaluation and clinical study of natto with reduced MK-7 produced by mutagenesis and special fermentation

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K05926
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38050:Food sciences-related
• Research Institution: University of Tsukuba
• Principal Investigator: HIRAMATSU Yuji 筑波大学, 医学医療系, 教授 (30302417)
• Co-Investigator(Kenkyū-buntansha): 長谷川 雄一 筑波大学, 医学医療系, 教授 (00251059) ; 加藤 秀之 筑波大学, 医学医療系, 講師 (00813643) ; 北村 豊 筑波大学, 生命環境系, 教授 (20246672)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 納豆 / ビタミンK / ワルファリン / MK-7 / PT-INR / 臨床試験 / 発酵 / 官能性

Outline of Final Research Achievements

Since natto contains a large amount of vitamin K (MK-7) produced by the bacillus natto, consumption of natto is prohibited for patients taking warfarin. However, there are strong requests from patients who want to eat natto, and based on the natto vitamin K reduction technology that our group has been developing, we conducted a food function evaluation of “low vitamin K natto” and clinical trials with warfarin-treated patients. The functionality and sensory properties of the food were tested. Then, a multi-stage clinical study was conducted with healthy subjects and patients taking warfarin, and it was confirmed that there were no significant changes in PT-INR and blood MK-7 concentration before and after the ingestion of the food.

Free Research Field

心臓血管外科

Academic Significance and Societal Importance of the Research Achievements

納豆というほぼ日本固有の伝統食品が研究開発対象であるため、東アジアを含む国外での同様の研究履歴は見当たらない。国内では、ワーファリンを取り扱う製薬企業がかつて大手納豆製造販売業者と共同して納豆のビタミンK低減化を企図した形跡があるが、特許取得には至っておらず、また開発技術の詳細も公表されていない。本研究課題は発想、方法論ともオリジナリティに富み、食品工学・栄養科学・臨床医学の叡智を集めて食卓への納豆復活を望む患者の声に応えたものである。ビタミンK低減化納豆の製品化は医療現場の固定観念や常識を覆すのみならず、患者およびその家族の日常食への浸透は一定の経済波及効果をもたらすものと推定される。