The 5th International Symposium on Clinical Nutrition (4-7 Feb 1996)
Volume 5,
Number 4, Section 2
The 5th
International Symposium on Clinical Nutrition (4-7 Feb 1996)
Hsu-Hage BH-H
The main objective of this paper is to review epidemiological studies with special reference to nutritionally-related diseases in Australia. In order for us to better appreciate the background as to why, how and what, Australian researchers and government agencies have accomplished in the field of nutritional epidemiology this paper will begin with a brief overview of the three axioms in epidemiologic studies in the context of Australia. They are: the Australian continent (the place), the changing composition of Australian populations (the people) and major events in Australia's history of food and nutrition (the time). The apparent relationship between food and health was once described by Brillat-Savarin in 1825 who stated "Tell me what you eat, and I shall tell you what you are". This paper will review food consumption patterns of Australians at large and of special groups. This is followed by an overview of disease patterns and mortality trends. Finally, we will examine studies of food and health in relation to chronic diseases in Australia and discuss public health implications for disease prevention and control.
Gu Jingfan
The traditional Chinese dietary pattern is characterised by high intakes of cereal and vegetables but low intakes of animal foods and the incidence of cardiovascular disease and malignancy has been relatively low. But in recent years, with the transition of dietary patterns, malignancy and cerebrovascular disease have become the first and second main causes of death. The incidence of acute coronary diseases is higher in urban populations, while acute cerebrovascular diseases are higher in rural ones, corresponding to higher dietary fat and lower animal protein, respectively. Hypertension and hyperlipidaemia have become two main risk factors of cardio-cerebro-vascular diseases. Although the serum lipids of the Chinese on average are lower than in western countries, their relations to dietary factors are still very significant. The dietary sodium showed positive correlation while dietary animal protein and calcium showed negative correlation to blood pressure. The hypertensives usually had lower serum linoleic acid and higher serum S/P ratio. After 3 years of intervention on stroke risk factors, including dietary control, the incidence declined markedly.
A case-control study of lung cancer showed that dietary carotene, vitamin C and fibre might reduce the risk. Similarly, eating fresh vegetables, fruits and bean products might reduce the risk of stomach cancer. b-carotene and vitamin C were proven to have a protective effect against the development of precancerous gastric lesions. The nutritional intervention trial in Linxian showed that supplementing micronutrients (b-carotene, selenium, vitamin E) for 5 years reduced the RR (relative risk) of oesophageal cancer incidence and death. Higher intakes of meat and edible oil were risk factors of colorectal cancer, while higher intakes of vegetables were protective factors. These protective effects were not only related to amounts, but also to sources, for example, only vegetable fibre and animal calcium showed the protective effect on colorectal cancer. In summary, high total energy, high total fat, low animal protein, high salt, low calcium, low vegetables and low fruits in the diet may increase the risk of cardio-cerebro-vascular diseases and cancers. A rational dietary pattern is important in prevention of these diseases. There needs to be more research work in the field of nutritional epidemiology to further investigate the role of dietary factors in China.
Sastroamidjojo S, Sudardjat Sri Sukmaniah, Sarwono Waspadji
Indonesia started its development after World War II when food shortages, famines, population pressures and poverty were rampant. In its developmental process, it also experienced rapid technological development and immense urbanisation.
Indonesia has succeeded in increasing its food production, controlling its population growth and improving the country's socioeconomic conditions. Invariably it has led to rising affluence, an aging population, change in life style and food cultural shifts, which is reflected in the nutritional status of the Indonesian population and especially the (nutrition related) disease pattern.
There is a tendency for an increasing prevalence of obesity, hypertension, lipid abnormalities, diabetes mellitus and coronary arterial disease.
Yuichiro Goto
Japanese dietary situation is characterised as follows: (1) Intake of total energy has been unchanged over 30 years at: 2,000-2,200 kcal. (2) Animal and vegetable components in protein and fats are almost equally balanced. Average intake of fish is a little more than meat. (3) A variety of vegetables such as root vegetables, green vegetables, mushrooms and seaweeds are taken daily. Dietary changes after the Second World War began in 1965. Accompanying Japan's economic growth, intake of meat, milk and dairy products, and fats and oil increased, while that of rice and salt decreased. In accordance with these situations, cerebrovascular disease declined and the mortality rates of ischaemic heart disease, diabetes mellitus, liver cirrhosis increased.
Leelahagul P, Achariyanont P, Soipet S, Pakpeankitvatana R, Tanphaichitr V
Although poor-rural Thais are still facing nutrient deficiency diseases affluent-urban Thais are encountering diet-related chronic diseases like the Western population. The common diet-related chronic diseases in Thailand are atherosclerotic vascular diseases, dyslipidaemia, hyper-tension, diabetes mellitus (DM), obesity, osteoporosis, and cancer. Based on data obtained from death certificates compiled by the Division of Health Statistics, Bureau of Health Policy, Plan Office of the Permanent Secretary, Ministry of Public Health during 1989-1993, there are increases in Thai mortality rates due to disease of the heart, hypertension, cerebrovascular disease, and cancers. Non-insulin dependent diabetes mellitus is the most common type of DM found in Thai population. The mortality rate of DM in Thai population increased drastically from 1989 to 1993. Our studies in epidemiology of chronic diseases in affluent-urban Thais show higher prevalence of coronary heart disease (CHD), dyslipidaemia, and obesity in populations with higher age groups and with high total energy and fat intakes. The major type of dyslipidaemia in the affluent-urban Thais is hypercholesterolaemia due to elevated serum low density lipoprotein-cholesterol (LDL-chol). The prevalence of hyper-tension in men is higher than in women. Affluent urban Thais face the problems of overall and abdominal obesity. Those with abdominal obesity have significantly higher serum total cholesterol, LDL-chol, triglyceride, uric acid, fasting blood glucose, 2-hr postprandial blood glucose and blood pressure levels but lower serum high density lipoprotein-cholesterol levels than normal subjects. Thus they are at risk for the development of CHD.
James WPT
The dramatic changes in national health revealed in this session present a formidable challenge at a national level for health service and for individual consumers. Traditionally, policy-makers thought of prevention and the health service and consumers of treatment but this is a mistake at all three levels since prevention and therapy are often closely linked.
The neglect of preventive strategies by the health service is understandable because of the dramatic therapeutic benefit displayed by drug use but prevention needs to be built in.
Clinically, the Asian doctor is at an advantage when coping with the major chronic diseases of diabetes, obesity or coronary heart disease because proposed dietary strategies, developed for European or American patients, would ideally require the patient to assume many of the characteristics of a traditional Thai, Chinese or Japanese diet. This is achievable more readily in Asia than in Western patients. The latest WHO preventive recommendations take account of dietary variations across the globe and are relevant to individual therapy which should be linked to family based preventive strategies. The linking of therapy to prevention will be illustrated for coronary heart disease, hyperlipidaemia and hypertension with an emphasis on the value of dietary change in preference to drug therapy. Diet should also be used when drug therapy is necessary.
The preventive challenge extends to cancers as revealed by the regional epidemiological data, new mechanistic insights (in relation to phyto-oestrogens in relation to breast cancer) and new data on the physiological effect of diet (resistant starch, faecal bulking and the prevention of colonic disease).
The Asian challenge, therefore, is how best to persuade doctors to advocate the importance of maintaining many (but not all) of the traditional features of an Asian diet. This advocacy should be consistent at the national level, hospital level and individually, when communicating with patients.
Bray G
Obesity has many causes, including hypothalamic injury, endocrine disorders, a high intake of dietary fat, sedentary lifestyle, medications and genetic disorders. Two syndromes of obesity following hypothalamic injury, one which results from hyperphagia and one from disordered control of metabolism by the autonomic nervous system. Cushings disease and the polycystic ovary syndrome are two endocrine causes of obesity. A high intake of dietary fat readily produces obesity in experimental animals, but the data in humans are less convincing. A sedentary lifestyle is an important factor in the obesity of the aging. Phenothiazines, tricyclic antidepressants, glucocorticoids, and some anticonvulsants can cause weight gain. Genetic factors operate through single genes or multiple genes. The discovery of leptin, the product of the ob-gene has opened a new vista for the study of genetics in obesity as have the genome mapping systems.
Obesity, central fat deposition and weight gain in adult life all enhance the risk of early mortality, cardiovascular disease, diabetes mellitus and some forms of cancer. Intentional weight loss will lower the risk of excess mortality from all of these causes.
James WPT Rowett
Over the last 20 years the management of obesity has been dominated by the results of clinical trials which lasted only for weeks. Such short trials were conducted because doctors are used to rapid drug effects, such as with blood pressure, liver damage or glucose control. Such approaches to obesity therapy are useless because obesity reflects the impact of at least 100 000 excess kcalories in someone who is marginally obese (BMI >30) and 1.65m tall. Traditionally, dietitians advocated diets to induce losses of about 1000 kcal daily, not recognising that this traps the patient into a window of physiological response where extraordinary willpower is needed to overcome the intense desire to eat; animals and humans devise ways of increasing intake when they are food deprived. The energy load in adipose tissue seems to be a bottomless sink which, despite recent findings on the ob-gene, does not dampen food intake once accumulated.
Thus, clinically, there are three main options: (a) reduce carbohydrate intake <50 g/day to induce ketosis and anorexia; (b) manipulate the diet to produce an energy dilute diet which, by gastric bulking, counteracts adaptive responses to a deficit of only 500-600 kcalories; (c) drug therapy. Option (a), with a very low calorie diet (VLCD), is a short-term manoeuvre but now safe with suitable diets. It requires difficult relearning of a new eating pattern to prevent weight regain. Option (b) is currently being assessed. Drug therapy is improving but has to be combined with a dietary approach and essentially should be long term as for treating hypertension. New drugs will be discussed. The surgical option is gaining favour for severe obesity because of the remarkable Swedish finding of less mortality and morbidity after gastroplasty.
Each therapeutic strategy should be considered over at least two years. In medical or non by-pass surgical management, energy intake has to fall permanently by 300 kcal for a 10kg weight loss unless modest but permanent increases in physical activity, such as an extra two hours of walking per day, to induce the use of about 300kcal/d extra. These demand major behavioural changes.
Mo-suwan L, Junjana C, Puetpaiboon A
Childhood obesity was shown to increase in prevalence in urban areas. The purpose of this study is to demonstrate the tracking of obesity in school children and investigate the influence of weight control programs on the obesity indices. Subjects were primary school children (grades 1-6) residing in Hat Yai municipality enrolled in 1991. Anthropometric data were collected on a yearly basis. Obese children were invited to participate in the weight control program. Results: From 2255 subjects recruited in 1991, follow-up could be completed in 1787 children (79%). Tracking of weight status using BMI percentiles based on NCHS reference was shown in the table.
Three-fourths of children in the upper 15 centiles (obese group) were still in the same centile while 24.5% had BMI in the normal range. There were no significant differences of BMI and triceps skinfold thickness between the obese children who participated in the weight control program and those who did not. Our findings show that tracking of obesity in this age group is high and weight control program has no long term effect on the outcome of obesity.
| 1991\1995 | <P15 | P15-<P25 | P25-P85 | >P85-P95 | >P95 |
| <P15 | 76 | 46 | 35 | 0 | 0 |
| P15-<P25 | 65 | 66 | 109 | 0 | 0 |
| P25-P85 | 24 | 92 | 888 | 77 | 5 |
| >P85-P95 | 0 | 0 | 66 | 92 | 23 |
| >P95 | 0 | 0 | 8 | 36 | 78 |
This study was funded by Songklanagarind Hospital Foundation.
Ismail MN, Tee AC, Zaini A, Haggarty P
The knowledge of total energy expenditure is important in order to estimate energy requirement for individuals or population groups. Seven normal (mean BMI 22.6) laboratory technicians (urban group) and 7 low-normal (mean BMI 18.6) rubber estate workers (rural group) participated in the study. The parameter measured include anthropometry, 3-day food intake and daily activity pattern, BMR and total daily energy expenditure (TDEE) using the factorial and DLW techniques. Mean energy intakes were higher in rural (8.4±1.3MJ/day) as compared to urban group (7.4±1.2MJ/day). Comparison between the predicted (FAO/WHO/UNU) equation and measured BMR (Deltatrac) revealed that the former overestimated the BMR of urban subjects by 5% and rural subjects by 10%. TDEE of urban subjects showed that the factorial method was about 11% lower then the DLW method while rural subjects recorded 2% higher than that obtained using DLW. The physical activity level (PAL) estimate for urban and rural groups were 1.59 and 1.69, respectively, reflecting a more sedentary lifestyle of the urban group. DLW has provided us with another set of data to validate previous reported local studies and lend support that energy requirements may be lower in the tropics. It is hoped that more DLW studies could be carried out in developing countries to enable us to keep abreast with the recent advances in stable isotope research in human nutrition.
Fulgoni III V
Recent advances in physiological impact of dietary fibre include a better understanding of effects of particular fibre sources (wheat bran, oat bran, psyllium, etc.). Wheat bran has been used as the "gold standard" in faecal bulking (regularity) studies. Several other research efforts have evaluated the effects of wheat bran on risk reduction of colon and breast cancer. A review of 17 experiments regarding wheat bran and chemically induced carcinogenesis indicated thirteen of these studies demonstrated a protective effect of wheat bran against colon tumour development. These data led to the conclusion that wheat bran appears to inhibit colon tumour development more consistently than other fibres (LSRO 1978). Recently Shivapurkar et al. (1995) has reported that raw wheat bran, Kellogg's® All-Bran® and Kellogg's® Complete® Bran Flakes all dramatically decrease aberrant crypts (early recursor of colon tumours) in rats. Two recently published human studies have examined the effects of wheat bran on colon cancer biomarkers specifically recurrence of colorectal adenomas and bile acid excretion (MacLennan et al, 1995; Alberts et al, 1996). Early animal model cancer studies indicate that high fibre diets including wheat bran can lower mammary tumour incidence and burden as compared to lower fibre diets. One way fibre may affect breast cancer risk is by lowering circulating oestrogen levels. Rose et al (1991) have shown that wheat bean preferentially lowers circulating oestrogen levels as compared to oat bran and corn bran. These and other data will be presented and discussed in greater detail.
Du Shoufen, Liu Cunying, Li Ling, Ke Meiyun
Soluble dietary fibre (DF) has been shown to have better effect on glycaemic responses than insoluble DF. One of the possible mechanisms appears to slow gastric emptying and increase the intestinal transit time (TT). To investigate the differences between soluble and insoluble DF on TT, normal diet (10-20g DF), high soluble DF diets (normal diet with 10g of conjac) and high insoluble DF diet (40-50g DF) were given to volunteers. In order to determine TT, radio-opaque pellets were used as markers. Several X-ray plain abdominal films were taken at the prescribed time until the markers were evacuated substantially. Mean mouth to ileum transit time (M-ITT), colonic transit time (CTT) and total gastrointestinal transit time (TGITT) were selected as indices. The results were as follows:
(*P<0.01, compared with normal diets). Our results suggested that soluble DF - conjac decrease TGITT as well as insoluble DF.
Copyright © 1996 [Asia Pacific
Journal of Clinical Nutrition]. All rights reserved.
Revised: January 19, 1999.
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