Toshio Kawabe

Stable carbon and nitrogen isotopic composition of diet and hair of Gidra-speaking Papuans

The carbon and nitrogen stable isotopic composition of the scalp hair and diet of Gidra-speaking people in four villages in Papua New Guinea is presented. The isotopic composition of hair was measured, while that of the diet was estimated from food consumption survey data and the measured isotopic composition and protein and carbohydrate contents of food items. The average isotopic ratios of the hair samples and of the diet varied among the four study villages, which were selected because of their diverse ecological settings. Comparison was made between hair and calculated dietary isotopic compositions. Two of the four diet-hair enrichment values obtained for 13C (+1.8 and 2.2%) were similar to those previously reported (1.4-2.0%), but the other two values (3.7 and 4.8%) were greater than in earlier reports. 15N enrichment was systematically greater (by 1.0%) than reported values (4.3%) except for one village, where a much greater enrichment (6.9%) was found. The factors potentially relevant to these deviations are discussed. Possible errors in estimating the dietary isotopic composition and minor modifications of dietary habits revealed by food consumption surveys could explain most of the discrepancies. However, the great enrichment of 15N found in one of the villages remains unexplained.

Elemental composition of ancient Japanese bones

Excavated bones (rib) obtained from 50 sites in Japan were measured by ICP atomic emission spectrometry and atomic absorption spectrometry for concentration of 19 elements, including Al, B, Ca, Cd, Cr, Co, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Sr, Ti, V and Zn. One hundred and forty-one specimens were classified into five groups according to Japanese prehistoric and historic eras (Jomon, Yayoi, Kofun, Kamakura and Muromachi, and Edo). The elements, with concentrations which showed no significant change with era were Al, B and Cr. Average concentrations of Ca were in the range 2-2.5 X 10(-1) g g-1 and those of P ranged from 1.1 to 1.3 X 10(-1) g g-1, indicating a well-preserved bone mineral matrix. The Ca/P ratio (mol/mol) was lowest in the Edo group--1.48 as compared with 1.54-1.66 in the other groups. Among the elements which showed changes with era were Pb, Fe, Co and Mn, all of which showed remarkably elevated concentrations in the Edo group. In addition to this unique elemental composition of Edo bones, samples from the Kofun era showed a completely different composition from those of other periods, i.e. they had the highest concentrations of Cd, Zn and Mg, and the lowest concentrations of Cu, K, Ni and Sr. The cause of the elevated Pb concentration in Edo bones is discussed in relation to human activities which may have led to environmental Pb pollution.

Mercury concentration correlates with the nitrogen stable isotope ratio in the animal food of papuans

The relationships among element concentrations (Na, Mg, Al, P, K, Ca, Cr, Fe, Mn, Cu, Zn, Sr, total Hg, organic Hg, inorganic Hg, Pb) and stable carbon and nitrogen isotope ratios (13C/12C and 15N/14N) in animals consumed by the people called Gidra, who inhabit the lowland of Papua New Guinea, were examined. Animals analyzed included mammal, bird, fish, shellfish, reptile, crustacean, and insect. Highly significantly positive correlations were observed between total Hg concentrations and 15N/14N (r = 0.796), between organic Hg concentrations and 15N/14N (r = 0.781), and between inorganic Hg concentrations and 15N/14N (r = 0.739). This was interpreted to indicate that Hg was an element which accumulates in animals along the food chain. Based on the regression function of Hg on delta 15N, the bioconcentration factor for total, organic, and inorganic Hg was estimated to be 5.

Diversity and change of food consumption and nutrient intake among the Gidra in Lowland Papua

Food consumption and nutrient intake of the Gidra in lowland Papua, who number 1,850 and inhabit 13 villages, were analyzed by compilation of five two‐week (or twelve‐day) records, in a single village in 1971 and in four different villages (including the above village) in 1981. The nutrient intake of the Gidra varied both over time and among the villages. Difference in food consumption patterns included different proportions of plant staples such as sago flour, garden crops and purchased cereals. The animal protein sources, mainly game and fish, also markedly varied among the villages. These differences in food consumption were related to environmental conditions such as the fauna and flora in the environment of each village and to the degree of modernization as reflected in ability to purchase foods not locally grown. The causal relationship between ecological (environmental and cultural) conditions and food and nutrition is discussed, and a schematic model for this relationship is presented.

Carbon and nitrogen isotopic characterization for Papua New Guinea foods

Stable carbon and nitrogen isotope ratios of the animal and plant food of the Gidra, who inhabit lowland Papua New Guinea and subsist mainly on hunting, gathering and horticulture, were measured to characterize the nutritional input of carbon and nitrogen of the Gidra. All the staple plant foods of the Gidra, such as sago and tuberous crops, were classified as C3 plants from their 13C/12C ratios (δ13C). The δ13C of the terrestrial mammals varied to a considerable extent (—11 to —26.5 per mil); the highest value was observed for a species of wallaby inhabiting savanna grassland while two other species of wallabies inhabiting woodland were —25.3 and —22.8 per mil. The δ13C of the aquatic animals was distinctive between marine (—17.0 to —7.1 per mil) and freshwater (—34.6 to —24.0 per mil) groups. The δ15N of the fishes and reptiles were generally higher than terrestrial animals. Major foods of the Gidra were isotopically divided into 5 groups: C3 plant, C3 plant feeder, C4 plant feeder, marine animal and fr...

Element intake of the Gidra in lowland Papua: Inter‐village variation and the comparison with contemporary levels in developed countries

Intake of 17 elements (Na, Mg, Al, P, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn Sr, Cd, Hg and Pb) was estimated in four villages of the Gidra in lowland Papua New Guinea. Among these elements, inter‐village variation of intake was relatively large for Na, Al, V, Fe, Ni, Cd, Hg and Pb. The variation was attributed to the different concentrations in foods and drinking water, and the differences in food consumption by different villages. Compared to the intake levels reported in Japan, the USA and European countries, Na, Ca, Ni, Cd and Pb intake in the Gidra was low. Low Na intake was principally caused by low consumption of salt. Low Na and Ca intakes were attributed to the low levels of consumption of animal foods. On the other hand, Mg, Al, K, Mn, Fe and Sr intake levels in the Gidra were high. In particular, extremely high Fe intake was attributed to region‐specific foods such as sago, wild seeds and shellfish.

Compositional character of Papuan foods

In 78 food samples collected in the Papuan lowland, concentrations of major nutrients and trace elements (Na, Mg, A1, P, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Cd, Hg, and Pb) were measured. Principal components analysis of local foods distinguished animal foods from plant foods: factor 1 had large positive loadings on protein, Na, P, Zn, and Hg contents and negative on carbohydrate content, and factor 2, positively on Mg, Ca, Mn, and Sr contents. Elemental concentrations differed among four categories of animal foods: mammals, birds, reptiles, and fishes. The highest levels of Fe, Cu, and Zn were found in mammals; the concentrations decreased in birds, reptiles, and fishes, in that order. In contrast, Ca and Sr were abundant in fishes but not in mammals.

Salt consumption, body fatness and blood pressure of the Gidra in lowland Papua

The Gidra population in lowland Papua New Guinea, having lived as a no‐salt culture, is now subjected to modernization. In 1981, salt consumption, body fatness and blood pressures were measured for people in four ecologically different villages. Daily salt consumption of individuals was estimated from the sodium level per unit weight of creatinine in the morning urine and the daily urinary excretion of creatinine (estimation from fat free mass). The estimated value significantly correlated (r=0.53) with actually measured value in 30 selected subjects. Estimated sodium consumption and the urinary sodium potassium ratio were generally lower in remote villages from the town, and the salt consumption levels were less than 5 g/day/person in all the villages. Body fatness, calculated from the two skinfold values, was variable with sex, age group and village, the most being in the females in a coastal village which was adjacent to the town. The age‐related increment of blood pressures was significant only in fem...

Mineral content of drinking water in lowland papua

This study presents concentration of nine minerals (Na, K, Mg, Ca, Cl, Mn, Zn, Cd, Pb) in 31 drinking water samples collected in the Papua New Guinea lowland, where coastal villagers draw water from artificial wells blended with sea water, riverside villagers utilize brackish river water, and inland villagers fetch creek or swamp water whose chemical composition is close to rain water. During the dry season, the coastal well water contains 500 mgL−1 of sodium and 50–90 μgL−1 of lead. The inland creek or swamp water contains very small amount of minerals; on the average, for instance, 0.64 mgL−1 of magnesium, 0.84 mgL−1 of calcium, and 4.78 mgL−1 of water hardness (as CaCO3). From some epidemiological evidence in industrialized countries, these mineral concentrations are judged to be indicative of high risk of cardiovascular disorders.

Dietary selenium intake of the Gidra, Papua New Guinea

Selenium (Se) concentrations in the food of the Gidra‐speaking people of Papua New Guinea were measured by fluorometry. Animal foods contained Se in larger concentrations than plant foods. Animal foods of aquatic origin contained more Se than those of terrestrial origin. Stepwise multiple regression analysis revealed an association between Se and the animals mercury content. Se concentrations in rice and wheat flour, which were imported from outside of the Gidra land, were more than one order higher than those in locally grown plant foods. The dietary Se intakes of the Gidra in four villages with diverse ecological conditions were calculated based on food consumption survey data. They varied from one village to another: the highest Se intake was observed in the coastal village (132.9 μg/adult male/day), which had greatest fish and purchased food consumption. It was followed by the riverine (97.8) and northern (51.0) villages, and the lowest intake was in the inland village (49.0), where no aquatic animal...