Changes in Relative Height of Children in Northeast Asian Countries in Fifty Years Since 1960

Economies in Northeast Asia made rapid and steady progress in the past half century, since 1960. Food consumption improved remarkably. Total calorie intakes increased first, followed by steady increments in animal sourced foods. Children became appreciably taller in height. In the mid-2000s, teens in South Korea were the tallest, 3cm taller than their Japanese and Taiwanese peers. In terms of per capita consumption of animal products, S. Korea was apparently the lowest. Genetics, however, fails to explain. A century ago, young men in Korea were 2 cm taller than Japanese but 3 cm shorter than Taiwanese. Since the mid-1970s, S. Koreans have been taking 2-300 kcal/day more overall food calories and twice as much vegetables than both Japanese and Taiwanese.


Introduction
Stature is a net measure that captures not only the supply of inputs to health but demands on those inputs (Stature and the Standard of Living) [1]. Japan's economy recovered from the war devastation to the pre-war level in 1955 and made rapid and steady growth toward the 1990s, despite the two world-wide oil-crises.
The standard of living increased and food consumption improved appreciably in quantity and quality. Per capita meat consumption, for example, increased from 7-8 kg/year in the pre-war years to 27 Young men in Japan may have reached racial/genetic potentials.
In 1980, young men, 20 years of age, in the Netherlands were 184 cm tall in mean height and 10 and 15 cm taller, respectively than those in France and Portugal. Some 100 years ago, in 1860-70, those in the Netherlands were 165 cm in mean height, only 1-2 cm taller than their peers in France and Portugal [3]. The author surmises that it should be too easy to attribute the differences in height observed at the given period of historical time between countries in the same region on the earth to racial or genetic traits. In terms of per capita caloric intakes from animal products, Portugal was 500 kcal/day, as compared to 1112 kcal/day for the Netherland in 1970 [4], for example. It is widely recognized in the arena of human biology that consumption of "high-quality proteins" is highly correlated to human height [5][6][7]. Little questions remain about this. When the cases of three countries in Northeast Asia are examined, however, attributing human height developments to animal proteins alone seems to have proved empirically questionable [8,9]. aside, Japanese boys were 2-3cm taller, regardless of age groups, than their peers in S. Korea and Taiwan in the 1960s through the mid-1970s, only slightly, 1 cm or less, taller in the mid-1980s and then ceased to grow significantly taller in height, whereas boys in S. Korea and Taiwan kept growing taller appreciably to overtake their peers in Japan by 2 cm in the mid-1990s. Boys in S. Korea kept growing further to surpass their Japanese peers by at least 3cm in the mid-2000s. Boys in Taiwan, however, became slightly shorter since the late-1990s, to be as tall as their Japanese peers in the late-2000s, for unidentifiable reasons.   As the economy grew, the inputs to health improved and stature increased accordingly. This happened unequivocally in the past half century in Northeast Asian countries. In respect of per capita GDP, however, Japan was the richest, followed by Taiwan, with S. Korea very far behind in the1980s. The bubble burst in Japan's economy at the outset of the 1990s, followed by the decade long stagnation.
In the beginning of this century, however, Japan was 25 % larger than Taiwan and more than 50% larger than S. Korea in per capita GDP (in purchasing parity US$), as shown in Figure 1 [13]. Table 2 demonstrates that per capita caloric intake from animal products in kcal/day, respectively in Japan and Taiwan over the corresponding period [4].

Steering Away from Fruit and Vegetables by Japanese Children
The author has been calling for attention to the wide-spread tendency of wakamono no kudamono banare in Japan (steering away from fruits by Japanese young) as a possible mal-impacts on child height growth. According to a few empirical cohort studies, consumption of fruit and vegetables have measurable impacts on bone mineral accrual for prenatal and growing children [16][17][18][19].
Boys reach their maturity in height at age of 17-18 years and girls a little younger, 16-17 years of age. "Inputs to health", or intakes of nutrients, both in quantity and quality, past these maturity ages rarely affect the human height development. When we discuss changes in child height between countries or over time, changes in per capita consumption by age groups, infants, pre-adolescence, and adolescence, and young adults, ---, should be desirable. Regrettably, these nutrition surveys, classified by exact age groups, seem to be too late in timing to identify child height development 1st-2nd graders in elementary school" [9].

National Health and Nutrition Surveys by
Starting in the early 1970s, Family Income and Expenditure Surveys (FIES) [23], Japanese government the Bureau of Statistics publishes household purchases (=at-home consumption) of various goods and services, classified by age groups of household head (HH). The author and his associates designed a simple but robust model to derive per capita at-home consumption by household members by age from FIES annual data, by explicitly incorporating family age structure by HH age groups [24,25]. Tables 4 and 5 provide the author's estimates of per capita at-home consumption of fresh vegetables and fresh fruit by age groups of family members, from the early 1970s to 2010 in Japan. Notes: Estimated by 5-year age intervals first, which were simply averaged into 10-year intervals.  not care for fresh fruit, because they find it of nuisance to peel the skin off. Instead, they drink fruit juice [26]. This contention is not founded statistically. Total shipments of fruit juice and drinks declined from 2,000 kilo-litters in the early 1990s to 1,500 kilolitters in the late 2000s [27]. Todays' Japanese children simply do not care for fruit, fresh or juice. In these regards, children and young adults in South Korea do not seem to have steered away from either vegetables or fruit in the turn of the century, as shown in Table 6 [28]. This statement does not imply the betterment or worsening in nutritional intakes past these early years of life has nothing to do with the final development of human height. See [2,9]. behind Taiwan and Japan in terms of per capita GDP. In respect of per capita caloric intakes from animal products, South Korea was distinctly lower than Japan and Taiwan. Are Koreans genetically taller than Japanese? Probably so. But young men in Korea were 3cm shorter than their peers in Taiwan a century ago, when the two countries were under Japan's colonization.
People in South Korea have been taking 2-300 kcal/day more food calories than people in Japan and Taiwan and eating nearly twice as much vegetables in various forms of kimchi as people in both Japan and Taiwan since the mid-1970s. "Population consuming larger amounts of animal protein reach higher average height than countries with less animal protein consumption" [29]. "However, a high consumption of animal proteins alone does not result in increasing body height if the overall consumption of calories and other essential nutrients is insufficient" [30]. This statement could apply to Japan and Taiwan in contrast with South Korea in the past few decades. Japanese children may have been insufficient in consumption of "essential nutrients" from vegetables and fruit in the past few decades in contrast with South Korea.