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Volume 5, Number 2, Section 3

Nutrition, ethnicity, and body composition

Aims of the meeting: The fast growing economies of the Asia Pacific Region in recent decades are bringing about changes in lifestyle and disease patterns in the region. Ethnic diversity and stage of development confound the way in which "Westernisation" has previously been defined. Increased dietary fat intake and increasing body fatness are said to hold the key to changing disease patterns, but how much more is there to it which ethnic diversity can reveal? The purpose of this meeting was to appreciate what human difference can impart to the understanding of nutrition, health and disease.

Organised by: Tianjin Municipal Bureau of Public Health, Tianjin Institute of Hygiene and Environmental Medicine, Chinese Nutrition Society, Asia Pacific Clinical Nutrition Society, Asia Pacific Health Nutrition Association.

Organising committee: Qu Xue-shen (Honorary Chair), Di Gui-zhen, Gu Jing-fan, Guo Ze-yu, Bridget Hsu-Hage (Secretary), Widjaja Lukito (Treasurer), Mark Wahlqvist (Chair), Gayle Savige, Dan Stroud, Naiyana Tikky Wattanapenpaiboon.

Acknowledgments: The conference organisers would like to thank the following companies for making the conference possible: NutraSweet Company, Servier International, Mars Incorporated, Tanita Health Equipment and Australian Dairy Corporation.

I. Ethnicity and body composition, plenary lectures

The imperative of gold standard methodology as a basis for ethnic comparisons of body composition

Boyd JG Strauss

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 115

Gold standards in body composition
Since the landmark concepts of Wang et al, in which different models of body composition have been given a strong biological and structured basis, what can be measured, and what we should strive to measure have become much clearer. The molecular, cellular and tissue/organ compartments all have strong clinical and health implications, for which many different techniques of body composition measurement are available.

At the molecular level, total body protein is measurable by neutron activation, total body water by dilution techniques, and something approaching triglyceride fat is assessed by DEXA. 1000

At the cellular level, ECF is also measurable by dilution techniques, and the cell mass is approximated by gamma counting. The structural materials of the skeleton are also measured by DEXA.

At the organ level, exciting advances in CT and MRI techniques have enabled organ volumes, particularly of visceral fat, to be measured.

However, a gold standard technique involves more concepts than a mere capacity to measure a particular component of a particular compartment. Issues arise of cost, portability, side-effects, applicability, and availability. The assumptions associated with each technique need to be clearly understood, and, not least, the role which these assumptions play in each human group or individuals who are measured.

Race, ethnicity and body composition
"Race" is characterised by a handful of phenotypical features, of which body composition is but one group, but genetic techniques have undermined the scientific validity of this categorisation. In general, phenotypic differences between classically described racial groups are only slightly greater than those which exist between nations, and both of these are small compared to the genetic differences within a local population.

Biological and genetic factors do not underlie ethnicity or culture, and it is common to produce biological explanations when the variable is politically or socially determined.

Recently, Senior and Bhopal have recommended that we should recognise that all current methods of classifying ethnic groups are limited, and that reports should state explicitly how such classifications are made. The potential for individual investigators to impose their personal values and ethnocentricity should be recognised. In considering differences in body composition between groups, consideration should be given equally and simultaneously to socio-economic, cultural or genetic factors.

References

1. Wang Z, Pierson RN & Heymsfield SB "The five-level model: a new approach to organizing body-composition research" Am. J. Clin. Nutr. (1992) 56: 19-28
2. Senior PA & Bhopal R. "Ethnicity as a variable in epidemiological research" BMJ (1994) 309: 327-30

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Body composition and disease: is there anything new to be learned?

Noel W Solomons, MD and Manolo Mazariegos, MD

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 116

The observation that disease has an effect on the tissues of the human body is as old as medicine, itself, and was not lost on preliterate and pre-technological societies. Primary changes in the amount, proportions or quality of total body mass, specific organs and specific tissues constitute pathologies; conversely, changes in body composition secondary to and conditioned by diseases are myriad. The classification of most of the associations has been roughly addressed. Nutritional and dietetic therapeutics allows us to intervene to change proportions of fat and lean, while surgery provides some leverage to modify and reconstruct organs and appendages and also to re 1000 move excess fat. With respect to these secondary changes due to illness, however, one must determine whether they are generally detrimental or adaptive/ accommodative before deciding to intervene. In the context of diet, body composition and ethnicity, ethnic groups differ with respect to their susceptibility to certain diseases and to the severity of their expression. Moreover, differences among different races in body composition are being documented systematically. The future holds in store the ability to analyse the molecular and chemical composition of the body. And we shall be able to focus not merely at the whole-body level, but at regional, segmental and even cellular loci. What must be kept in perspective is ensuring accessibility of the emerging technology to developing nations, as that is where the greatest diversity of both pathology and ethnicity is to be found.

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Body composition in the aged: its relevance to functional outcomes

Widjaja Lukito

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 116

Ageing is accompanied by changes in body composition - a reduction in fat free mass (FFM), which includes total body water, protein and bone mass, and an increase in fat mass (FM). Ageing is also complicated by reduction of physiological reserves, which lead to unfavourable changes in functional status. Frailty is more prevalent amongst the aged than their younger counterparts. Given that protein and bone mass constitute probably two of the most important nutritional reserves in the aged, it is therefore plausible that a reduction in these two lean tissues partly contributes to frailty and its adverse health outcomes, which range from falls to institutionalisation and death. It is necessary to identify frailty which can be prevented or reversed before it becomes irreversible. Underlying body compositional changes which may result in falls and infectious diseases should be recognised. Maintenance of desirable body composition in the aged would help maximise functional status and health outcomes.

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Nutrition deficiencies in the Asia Pacific region

Soemilah Sastroamidjojo

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 116

The twentieth century is marked for its impact on Nutrition not only because of its two world wars, but also by its rapid technological development and immense urbanisation.

The countries in the Asia Pacific region, which have fallen or still fall into the broad category of developing countries have had food shortage, famines, population pressures and poverty. In the developmental process, while famine is eradicated, population growth decreased and poverty slowly alleviated, invariable features have been the migration of populations from rural to urban areas and the influence of communication technology.

These development challenges have been met in varying degrees and led to rising affluence, an aging population, food cultural shifts and environmental degradation. One of the consequences of this developmental transition is a changing profile of nutrition deficiencies, which continue to contribute to classical deficiency states and now as well as CNCD (chronic non-communicable diseases).

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Diet and cardiovascular disease 1000 in the Asia Pacific region

Geok Lin Khor

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 116-117

There are major changes in the dietary intake patterns of countries in the Asia Pacific region in relation to changes in the trends of mortality due to cardiovascular disease. Cardiovascular disease constitutes the major cause of mortality in many of the countries in the region. The mortality rate for coronary heart disease (CHD) has been on the decline since the mid 1960s in some countries such as Australia, New Zealand and Japan, while the decline in other countries including Singapore and Hong Kong appear to be occurring about two decades later. In countries, other countries like Malaysia and China show an upward trend for CHD mortality. Nonetheless, the mortality rates due to CHD in New Zealand, Australia, Singapore followed by Hong Kong rank among the highest in the region. In China, Taiwan and Japan, cerebrovascular disease remains a major cause of death, although the latter two countries have undergone significant decline in stroke death rate since 1970.

The intake of fat from animal products, fish and vegetable oils need to be considered in the light of current knowledge of the different atherogenic and thrombotic effects of various fatty acids. Countries which have a higher mortality from CHD tend to have a higher intake of fat calories and proportion of fat from animal products. Related issues include the prevalence of hyper-cholesterolaemia and overweight in the various countries. Intakes of other items with CVD implications in the region such as soybeans, dietary antioxidants like vitamin E and -carotene, and alcohol consumption are also of consequence.

The wide dietary scope covering populations from diverse socio-cultural backgrounds and at different economic and technological development poses several challenges. Future research must be directed towards improving datasets for future decision making.

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Diet and cancer in the Asia Pacific region

Robert MacLennan

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 117

The relationships between ethnicity and nutrition are evident in the Asia Pacific Region, and there are extraordinary contrasts in the diets of its populations. The past ten to fifteen years has seen a large increase in studies of diet and cancer, especially in China and Japan, and the attempt to relate diet to the large variation seen in cancers of many sites. Rapid culture change has occurred in many countries and has been accompanied by new technologies, new industries and new food patterns. Cancers previously uncommon in Asia have increased with affluence and the adoption of more "Westernised" diets among sections of the population. Changes in diets have occurred with migration, and the evolution of cancer incidence following migration from China and Japan to North America has been comprehensively investigated. Studies of migrants, such as the Japanese in Hawaii and Europeans in Australia, suggest that many of the differences in cancer patterns among populations may be provisionally attributed to dietary factors, but much remains to be discovered. More than anywhere else, the Asia Pacific region offers opportunities for studies to better understand dietary carcinogenesis. To do this more information is needed about its culturally diverse populations, and should include dietary studies, and also cancer registration and ex 1000 pertise in nutritional epidemiology and environmental carcinogenesis. There is an opportunity in this region to develop new culturally based approaches to cancer prevention.

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Anthropological view of food and health

Zak I Sabry

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 117

Humans seek food not nutrients. Although foods stimulate the taste, visual, thermal and tactile senses, it is the mental representation of foods that makes us decide whether certain foods are edible or poisonous, liked or disliked. We often confuse preference with liking a food. Foods may be preferable for health or economic reasons. However, liking foods is more of a hedonic reaction. Furthermore, liking or preferring a food must be taken within an appropriate context, often specified by culture. Clearly, food choice influences nutrition and health status. This is why nutritionists become so pre-occupied with the determinants of food choice.

The determinants of food choice most often discussed are availability and economic factors. In addition, there are powerful biological and cultural determinants of food choice.

Among the biological influences are certain innate taste biases (preference for sweetness, possibly for caloric availability, and aversion to bitterness that may be related to association with toxins). and the often observed responses of neophilia that would drive us to try new foods and of neophobia that would make us fear them. There are also inherited metabolic characteristics of individuals and ethnic groups, such as lactose intolerance which curbs the consumption of milk in some populations.

The impact of culture on food preferences is immense in magnitude and in its health consequences. Some cultural influences are of no nutritional significance, having to do with who handled the food; others may have negative consequences often in response to infectious diseases in infancy; but there are many culturally-linked practices that have positive nutritional and health impact.

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Evaluating fat consumption trends in Malaysia

Kalyana Sundram

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 117

Fat consumption trends in Malaysia have gradually undergone major changes in recent years. While coconut oil consumption predominated about three decades ago, palm oil and its fractions have evolved as the dominant edible oil in this multiracial population today. Dietary fat energy approximates 25% of the total energy intake with a polyunsaturated/saturated fatty acid ratio of 0.3. Fatty acid analysis of duplicate 24 hour recall food samples from segments of the population shows that the composition is largely palm oil related: high palmitic and oleic and moderate linoleic. Often, lauric myristic fatty acids make up 7-10% of the composition suggesting the continued consumption of coconut oil largely as coconut milk and used to flavour traditional recipes. Dietary cholesterol intake is less than 300 mg/day. The availability of linoleic acid (about 3% energy) seems moderate whereas dietary omega-3 fatty acids are usually below optimum. The implications of this fat consumption pattern on blood lipid and lipoprotein levels and related coronary heart disease risk have not been properly evaluated. These pertinent public health questions are prese 1000 ntly being assessed through an ongoing epidemiological study evaluating dietary habits, fat consumption trends and fatty acid composition for their impact on coronary heart disease risk factors in an urban Malaysian population.

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Uni-ethnicity and environmental plurality - studies in Chinese food and health

Bridget H-H Hsu-Hage

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 118

The study of Chinese living in China and abroad provides a unique opportunity to examine the relationships between food and health in a population which is relatively homogeneous genetically. This means that variation in CVD risk profile observed between the Chinese populations in the different countries, and centres within the one country, is likely to be due to environmental differences. Food intake is potentially one of the most important environmental factors related to variation in CVD risk disease profile. The Monash Nutrition Research Group (MNRG) is studying food consumption patterns of Chinese populations living in China and Australia, and is examining factors associated with changing food consumption patterns at both individual and population levels.

Southern Chinese are a major donor population for overseas Chinese and are themselves ethnically diverse, as characterised by dialect spoken at home. Food consumption patterns of southern Chinese, unlike their northern counterparts, are traditionally high in rice accompanied by pork, fish, leafy greens, soups, and tea. Melbourne Chinese show a significantly lower intake of all these food items. The food consumption pattern of Melbourne Chinese is undergoing inevitable change and acculturation towards that of mainstream, but that is also changing, Australia. Traditional foods are replaced with wheat products, red meat, non-leafy type of vegetables, nonalcoholic beverages, and coffee. The nutrient intakes and food sources of nutrient also are changing.

These observations illustrate the socio-environmentally dynamic nature of food habits, conventionally regarded as static. The motivation for native southern Chinese populations to make changes to their eating practices may differ from that of self-selected Chinese immigrants to Australia. The consequences of changing eating practices in the two groups, drawn from different locations and socio-economic backgrounds, will merit further enquiry.

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Short communication. Body mass index of young adults in China

Ge K, Zhai F, Liu H

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 118

Body mass index of young adults aged 20 to 45 years was observed in connection with household income, energy and macronutrient consumption. The sample consisted of 8477 urban and 20911 rural subjects, a part of the 1992 China national nutrition survey.

The mean values of BMI were 21.5 and 21.9 for urban males and females, 21.1 and 21.5 for rural males and females. Inhabitants of three big cities presented a higher BMI value than the national averages. Undernourished people (BMI < 18.5) accounted for 9.0% of the urban and 8.0% of the rural populations, and the overweight (BMI > 25) constituted 14.9% and 8.4% respectively.

Across communities, the proportion undernourished is inversely rel 1000 ated to the average energy intake, and the overweight proportion is positively related to the dietary fat intake in rural populations. Recent trends in BMI change in China are connected to food consumption.

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Body composition of different ethnic groups in South Africa

Benadé AJS, Oelofse A, Faber M

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 118

Anthropometric information from the three main ethnic groups in South Africa, namely Africans, Whites and Coloureds, collected during the past five years and covering the age groups 0 to 64 years of age, were compared.

Prevalence of underweight for age (2 SD NCHS, WHO) was low for white children (3%) under two years of age whilst coloureds and Africans displayed rates double that observed for their counterparts. Prevalence of overweight in this age group was similar namely 5%. No difference was observed between urban and rural children or between males and females.

With increasing age however, marked differences in body weight were observed between ethnic groups, males and females and between urban and rural groups. Although the prevalence of overweight increased in all three ethnic groups with age, more whites tend to become overweight than either Africans or Coloureds (45%, 38%, 24% respectively). More rural females were found to be overweight than urban females (58%, 30% respectively). Obesity on the other hand was found to be almost two times as prevalent in urban than rural females (58 % and 30 % respectively) with the highest prevalence recorded in the African females (African 60%, Coloureds 44%, Whites 22%). This is in contrast with the white South African male who has a higher prevalence of both overweight and obesity than his ethnic counterparts.

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Ethnicity and nutritional status: a comparison of Indonesian and Dutch underfive children

Droomers M, Dillon D, Schultink JW, Gross R, Sastroamidjojo S

Asia Pacific Journal of Clinical Nutrition (1996) Volume 5, Number 2: 119

A cross sectional study to compare the nutritional status of Indonesian and Dutch underfive children was conducted in Jakarta, Indonesia.

A total of 168 Indonesian underfive children from high socio-economic class were recruited into this study. Their mean age, height and weight were 45.68 7.57 months, 101.5 5.4 cm and 17.2 3.3 kg respectively. Thirty-two Dutch under-five children who lived in Jakarta were also recruited for comparison. Their mean age, height and weight were 45.22 9.52 months, 102.6 8.1 cm and 16.2 2.7 kg respectively.

When height and weight were compared to the NCHS reference population, the Z score revealed that the nutritional status of both the Indonesian and Dutch children were equal to the NCHS American standard.

In this study, we observed that the nutritional status of Indonesian and Dutch underfive children living under the same socio-economic circumstances was similar. It was concluded that Indonesian underfive children have the same genetic growth potential as their western peers.

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Revised: January 19, 1999 .

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