Yuichi I Naito1, Ayako Morita2,3, Kazumi Natsuhara4, Kiyoshi Tadokoro2, Jun Baba5, Shingo Odani6, Eriko Tomitsuka2, Katsura Igai7, Takumi Tsutaya1, Minoru Yoneda1,8, Andrew R Greenhill9,10, Paul F Horwood9, Kevin W Soli9, Suparat Phuanukoonnon9, Peter M Siba9, Masahiro Umezaki2. 1. Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba, 277-8562, Japan. 2. Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan. 3. Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo, 113-8519, Japan. 4. The Japanese Red Cross Akita College of Nursing, Nawashirosawa 17-3, Saruta, Kamikitate, Akita, Akita, 010-1493, Japan. 5. The Research Institute for Languages and Cultures of Asia and Africa, Tokyo University of Foreign Studies, 3-11-1 Asahi-cho, Fuchu, Tokyo, 183-8534, Japan. 6. Faculty of Letters, Chiba University, 1-33 Yayoicho, Inage, Chiba, 263-8522, Japan. 7. Graduate School of Biomedical Science, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan. 8. The University Museum, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo, 113-0033, Japan. 9. Papua New Guinea Institute of Medical Research, PO Box 60, Goroka, Eastern Highlands Province 441, Papua New Guinea. 10. Federation University, Gippsland Campus Northways Road, Churchill, Victoria, 3842, Australia.
Abstract
OBJECTIVES: We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ(15) NHair-Diet : δ(15) NHair - δ(15) NDiet ) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ(15) N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ(15) N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ(15) N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants. MATERIALS AND METHODS: These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ(15) N was estimated by comparing hair δ(15) N values to mean dietary δ(15) N values calculated from the recorded intake of each food item and their δ(15) N values. RESULTS: The results showed that: i) there was a significant difference in Δ(15) N among study locations (3.9 ± 0.9‰ for most urbanized, 5.2 ± 1.0‰ for medium and 5.0 ± 0.9‰ for least urbanized communities; range = 1.2-7.3‰ for all participants); and ii) estimated Δ(15) N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range = 0.9-7.6%). DISCUSSION: We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ(15) N values of the participants.
OBJECTIVES: We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ(15) NHair-Diet : δ(15) NHair - δ(15) NDiet ) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ(15) N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ(15) N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ(15) N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants. MATERIALS AND METHODS: These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ(15) N was estimated by comparing hair δ(15) N values to mean dietary δ(15) N values calculated from the recorded intake of each food item and their δ(15) N values. RESULTS: The results showed that: i) there was a significant difference in Δ(15) N among study locations (3.9 ± 0.9‰ for most urbanized, 5.2 ± 1.0‰ for medium and 5.0 ± 0.9‰ for least urbanized communities; range = 1.2-7.3‰ for all participants); and ii) estimated Δ(15) N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range = 0.9-7.6%). DISCUSSION: We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ(15) N values of the participants.
Authors: Alison J T Harris; Ana T Duggan; Stephanie Marciniak; Ingeborg Marshall; Benjamin T Fuller; John Southon; Hendrik N Poinar; Vaughan Grimes Journal: PLoS One Date: 2019-01-07 Impact factor: 3.240