2022 Fiscal Year Final Research Report

Mechanism of adaptation to a low-protein diet observed among the indigenous population of New Guinea Island, whose primary sustenance revolves around sago starch.

Research Project

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Project/Area Number	20K11560
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 59040:Nutrition science and health science-related
Research Institution	Okayama Prefectural University
Principal Investigator	Irie Yasuyuki 岡山県立大学, 保健福祉学部, 教授 (70303948)
Co-Investigator(Kenkyū-buntansha)	井上里加子岡山県立大学, 保健福祉学部, 助教 (10508039) 國澤純国立研究開発法人医薬基盤・健康・栄養研究所, 医薬基盤研究所ワクチン・アジュバント研究センター, センター長 (80376615)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	低蛋白質食 / サゴ / 低栄養
Outline of Final Research Achievements	A comprehensive survey and collection of samples were undertaken among the ethnic minorities residing in the western region of New Guinea Island. Local physicians interviewed the traditional dietary group (n=25), predominantly reliant on sago palm, as well as the modern dietary group (n=25). Subsequently, they carried out medical examinations, dietary surveys, body composition measurements, blood tests, and analysis of intestinal microbiome. Moreover, alongside comparing the traditional diet group and the modern diet group, a comparative analysis of diet and nutritional status was conducted between the modern diet group and the elderly population in Japan. The protein intake of the traditional diet group was remarkably low, amounting to approximately half of that observed among institutionalized elderly individuals and inpatients residing in nursing wards. Nonetheless, none of the ethnic minorities on New Guinea Island exhibited protein-energy malnutrition (PEM) in either group.
Free Research Field	臨床栄養学
Academic Significance and Societal Importance of the Research Achievements	介護施設入所中の後期高齢者では PEMの者が多く、さらに、施設や病院で提供される食事を完食するにもかかわらず低栄養状態になる者、同じ食事をしていても低栄養にならない者がいる。現在は、低栄養の者に蛋白質摂取を目的とした補助食品の付加が行われているが、効果的とは言い難い。本研究では、ニューギニア島少数民族に、摂取カロリーは同等だが蛋白質摂取量が施設入所高齢者の半分程度と非常に少ない、サゴヤシを主とする伝統食を摂取する人々があり、彼らがPEMを発症しないことから、低蛋白食に適応する機構を持つことが示唆された。これは日本の高齢者におけるPEMの予防法や治療法の確立にも寄与すると考えられる。