1,720,991 research outputs found
Diet and physical activity as determinants of nutritional status in elderly women
No full textThe purpose of the studies described in this thesis was to examine the relationship between physical activity, dietary intake and nutritional status in elderly women.Background of the study was a lack of knowledge about the existence of nutritionally unfavourable pathways associated to the age-associated decrease in physical activity, leading to either overweight or nutrient deficiencies.A physical activity questionnaire was adapted and validated for use in elderly people and applied to perform a cross-sectional study in independently living apparently healthy women aged 60 to 80 years. Comparison revealed a marked weight difference, body weight being substantially higher in sedentary elderly women compared to women with a high level of physical activity. In retrospect, analysis of both body weights and physical activities showed that the weight difference was already prevalent at the age of 25 whereas no differences could be detected in former levels of physical activity. It was suggested that the currently low level of physical activity was more a result rather than a cause of a high body weight. Using a battery of tests to assess physical fitness it was shown that flexibility and endurance were associated to level of physical activity. Data were confirmed in findings on subjective fitness. Measurement of energy expenditure at rest and during standardised activities revealed that energy costs of walking on a treadmill were markedly higher in elderly than in middle-aged women.Conclusions of the study were that women with a higher body weight might be more likely to reduce physical activity with ageing. An explanation is that the age-dependent increase of energy costs of moving around makes the performance of physical activity unpleasant, especially in women with a high body weight
Body composition and diet of Chinese, Malays and Indians in Sininfluence on cardiovascular risk factorsgapore: and their
No full textThis thesis describes the studies on body composition and dietary intakes of the three major ethnic groups residing in Singapore, and how these are related to cardiovascular risk factors in these groups.Body composition : Body fat percentage was measured using a four-compartment model described by Baumgartner. When the relationship between body mass index (BMI) and body fat percentage was studied, it was discovered that Singaporeans have higher percentage of body fat compared to Caucasians with the same BMI and that the BMI cut-off value for obesity in Chinese and Malays is around 27 kg/m 2 , while that for Indians is around 26 kg/m 2 . At levels of BMI and waist-to-hip ratio which are much lower than the WHO recommended cut-off limits for obesity and abdominal fatness respectively, both the absolute and relative risks of developing cardiovascular risk factors are markedly elevated for all three ethnic groups. Both the excessive fat accumulation and increased risks at low levels of BMI signal a need to re-examine cut-off values for obesity among Chinese, Malays and Indians.Diet : Dietary intakes of energy, total fat, saturated fat, polyunsaturated fat, monounsaturated fat and cholesterol were measured using a food frequency questionnaire specially validated for this purpose. In addition, intakes of fruits, vegetables and grain-based foods were also measured using the same questionnaire. Singaporeans generally have a low intake of fruits, vegetables and whole grain products. The intake of total fat is just within the upper recommended limit while that for saturated fat is higher than the recommended level. On a group level, it is found that high intakes of fat, saturated fat and low intakes of polyunsaturated fat and vegetables affect serum cholesterol levels adversely. However, on an individual level, due to the rather homogenous intake patterns among the three groups, this cross sectional study was unable to demonstrate that dietary intakes could explain the differences in serum cholesterol levels among ethnic groups.In summary, the thesis shows that in the light of increased body fat percentage and cardiovascular risks at low BMI, there is a need to re-examine the WHO's cut-off values for the three major ethnic groups in Singapore. Longitudinal studies are also needed for better insight into the effect of dietary intakes and other lifestyle risk factors on cardiovascular risk factors and mortality.</p
Nutrition in adolescence : a longitudinal study in dietary patterns from teenager to adult = [Voeding bij jongeren : een longitudinale studie naar het voedingspatroon van de tiener- tot aan de volwassenleeftijd
No full textThis thesis reports the longitudinal changes in dietary intake of a group of Dutch adolescents, 103 girls and 97 boys from about 12 to 21 years of age (part of 'The Amsterdam Growth and Health Study'). The subjects were pupils of a secondary school, and measured five times. A dietary history method was used to assess the food intake. Special reference was made of differences between schooldays and weekend days. In girls the observed total energy intake was almost constant over the whole age range (9.5 mJ), whereas in boys the nutrient intake gradually increased with age from about 11 mJ/day at age 12, to 14 mJ/day at age 21. On weekend days the energy intake of girls and boys in all age-groups was consistently higher. Compared to the recommendations of the Netherlands Nutrition Council, the food intake of these teenagers contained too much saturated fat, and not enough poly-saccharides. In general, the mineral and vitamin intake was comparable to the recommendations. Only in girls the intake of iron was borderline. In both sexes some overconsumption of energy was likely, because during the period of study an increased percentage of body fat was found. Snacks supplied about 20-25 % of the total daily energy intake in both sexes (on weekend days about 30 %). The alcohol consumption increased strongly with age, from 1 g/day at age 13 in both sexes, to 7 g/day in girls and 18 g/day in boys at the young adult age. The teenage food pattern was compared with a Dutch meal-planning- disk. It is indicated that the nutrient definitions, given in this model, are too general. The food consumption was divided in a relatively high and low quality diet. Girls with a relatively high quality diet showed lower body fat mass and better physical performance (e.g. higher aerobic power). In boys no relationship could be demonstrated. Early maturing (skeletal age) girls and boys consumed less energy, but also showed a lower habitual physical activity and were fatter than late maturers.It is concluded that the dietary pattern of these observed youngsters was not different from the Dutch population in general
Assessment of flavonoid and fatty acid intake by chemical analysis of biomarkers and the duplicate diets
No full textDietary intake is important to investigate the relationship between diet and the occurrence of disease. However, it is difficult to assess the intake of nutrients such as flavonoids, minor fatty acids and plant sterols because the data on these nutrients in food composition tables are insufficient or because the bioavailability of these nutrients differs between foods. The results of studies investigating the relationship of these nutrients to disease are inconsistent, perhaps because of errors in the methods used to assess nutrient intake. The aim of this thesis was to evaluate physically and chemically based methods of measuring the intake of flavonoids, fatty acids, sterols and energy.We found differences of up to 80 mg per day in the intake of flavonols and flavones in subjects eating a variety of diets. The ratio of the within- to the between-subject variation in the intake of flavonols and flavones was lower than one, indicating that it is possible to study the relationship between flavonoid intake and disease. The food frequency questionnaire used in this study was suitable for classifying subjects by their flavonol intakes.We also found that the bioavailability of the flavonol quercetin differs between the major dietary sources. The bioavailability of quercetin from red wine was 75% of that from onions and from tea 50% of that from onions. Therefore, flavonols from red wine can probably not explain the lower incidence of coronary heart disease in France compared to other western countries. Concentrations of quercetin in plasma can be used as biomarkers to distinguish between subjects with a low and with a high flavonol intake. This is possible because of a relatively small variation of plasma quercetin and a linear relationship between quercetin intake to its concentrations in plasma and excretions in urine.Chemical analysis of food composites is a suitable method to assess the intake of a large number of fatty acids and sterols for subsamples of populations. We found large differences in the amount of these nutrients in the diets of middle-aged men living in 16 cohorts in seven countries. Three-day records are not suitable to measure individual energy intake, but they can be used to classify subjects by their energy intakes.In conclusion, the most feasible method to assess flavonol intake in epidemiological studies appears to be a food frequency questionnaire specially devised to assess flavonol intake and validated in a sub-population by biomarkers of flavonol intake. In addition, chemical analysis of food composites is a good tool to assess specific fatty acids and sterols in the diet of a population. Finally, when using 3-day food records, even from a motivated, lean, well-educated population, underestimation of intakes has to be taken into account
24-hour dietary recalls as reference calibration measurements in EPIC: from statistical theory to epidemiological application
No full textLarge multi-centre cohort studies have been set up with the aim of increasing the statistical power to detect an association between diet and disease by including study populations varying both in dietary exposures and outcome diseases. However, such studies raise also new statistical and methodological challenges to improve the comparability of dietary measurements collected from populations from different geographical and socio-cultural origins. In the European Prospective Investigation into Cancer and Nutrition (EPIC), involving half a million subjects from 23 centres in 10 European countries, a calibration approach was adopted to correct for systematic errors in individual dietary measurements obtained by means of different dietary assessment methods across centres, by re-expressing them according to the same reference scale (between-cohort calibration). 24-hour diet recall was selected as the reference calibration method in EPIC. In order to meet the theoretical requirements, such a reference calibration method must be highly standardized across study centres, provide accurate dietary estimates at the population level and should not be an obstacle to the collection of data from a representative sub-sample of the entire cohort. This thesis deals with translating the theoretical statistical concept of the calibration into an epidemiological application in the context of a large multi-centre study on diet and cancer.The thesis presents first some theoretical concepts of the main sources of measurement errors associated with the 24-hour diet recall method and the standardisation procedures used to prevent or minimize them in the context of a large multi-centre study. An ad hoc face-to-face computerized 24-hour diet recall interview programme (EPIC-SOFT) is then described as the end product used as reference calibration method across the EPIC centres. The rationale and a new theoretical concept of standardizing food composition tables in large multi-centre studies such as EPIC is discussed separately. In a second part, the design and the populations of the calibration sub-studies set up in each EPIC centre are described, as well as the representativeness of the calibration sub-sample compared to the whole cohort.In order to estimate the degree of standardisation of the 24-hour diet recalls across interviewers an analysis of variance was performed using mean total energy per interviewer as dependent variable. Furthermore, a validation study using urinary nitrogen as independent reference measurements was conducted to estimate the reliability of mean 24-hour diet recall measurements of protein (and total energy) for between-cohort calibration. Finally, the 36,900 24-hour recalls collected in EPIC were used to study the large heterogeneity in dietary patterns existing between the EPIC centres, using the same detailed dietary methodology.This was the first time that calibration sub-studies using the same dietary methodology has been set up in a large multi-centre European study. Despite inherent methodological and practical problems, the calibration worked well in a large multi-centre setting, and the calibration sub-sample can reasonably be considered to be representative of the entire EPIC cohort in most centres. The standardisation across interviewers and the validation of 24-hour diet recalls for between-cohort calibration shown encouraging results. However, measurement errors, particularly conscious or unconscious behaviour of respondents and/or interviewers, cannot be prevented entirely, and the problem of measurement errors and its determinants need to be considered in the application of the calibration, as well as day of the week and seasonal coverage. This first experience should also lead to additional improvements in the reference method and setting up nested calibration sub-studies in the future. Furthermore, it demonstrates that standardized dietary methodologies can be developed in an international context and opens perspectives for using the EPIC-SOFT programme or other approaches in large European nutritional studies
Household food security and nutritional status of vulnerable groups in Kenya : a seasonal study among low income smallholder rural households
No full textClimatic seasonality is now recognized as being a constraint to agricultural production and to household food security in many countries within the tropical regions of the world. This study investigated the extent to which a unimodal climatic pattern affects food production and food availability of smallholder rural households, with special emphasis on households with limited landholdings and low cash incomes. Further investigations involved looking at the effect of fluctuating levels of food availability on dietary intakes and the nutritional status of three vulnerable groups namely: preschool children, lactating women and the elderly. The study was carried out in Nakuru district within the Rift Valley province in Kenya between April 1992 and June 1993. Foods coming into the household from own production, purchases, and gifts were recorded on monthly basis from recalls. Body weight of all the subjects was measured once every month. Height was measured once at baseline for the adults, while length for preschool children was measured three times. Food consumption was determined by 24-hour recall method on monthly basis, and by 3-day weighed records at three points during the lean and the harvest seasons. A unimodal climatic pattern was found to influence food production and hence household food availability during most months within the production cycle. This subsequently influenced food consumption and the nutritional status of the vulnerable groups in the study. Lactating women lost up to 9 percent, elderly men 7 percent, and elderly women 3 percent of their body weight. While no weight losses were observed in the children, weight gains were minimal during the lean season but improved slightly during the postharvest period. It was observed that the energy and nutrient intakes of the children depended more on diet quality rather than on household food availability per se.</p
Nutritional status and growth of children on macrobiotic diets : a population-based study
No full textThis thesis reports on the relationship between diet, growth, blood chemistry, psychomotor development, and clinical findings in the Dutch population of children on macrobiotic diets.- The macrobiotic diet mainly consisted of cereals, pulses and vegetables with small additions of seaweeds, fermented foods, nuts and seeds. meat and dairy products were avoided, whereas fish was occasionally being eaten but not by young children. The total Dutch macrobiotic population was invited to join the study; the refusal rate was below 5 per cent. A cross- sectional anthropometric study in macrobiotic children between birth and 8 years of age (n = 243) revealed that the age curves declined from the P50 of the Dutch standard mainly between 6 and 18 months of age. A partial return towards the P50 was observed after 2 years of age for weight and arm circumference, but not for height. A subsequent mixedlongitudinal study in macrobiotic infants aged 4 - 18 months and a matched omnivorous control group showed that growth of the macrobiotic infants was slowest between 8 and 14 months. This was attributed to a lack of both energy and protein in the macrobiotic weaning diet. The observed growth retardation was associated with retardation in gross motor and language development. For calcium, vitamin D, vitamin B12 and riboflavin, a low intake in combination with biochemical evidence of deficiency was found. Rickets was present in 28 per cent of macrobiotic infants in summer and 55 per cent in winter. AS a favourable aspect, lower levels of contaminants were found in the breast-milk of macrobiotic mothers. It is concluded that nutritional deficiencies are present in a high proportion of macrobiotic infants. Continued marginal deficiencies in older macrobiotic children seem to prevent catch-up growth in height. It is advised to adapt the macrobiotic diet as to include fatty fish (100 - 150 g/week), oil (20 - 25 g/day) and dairy products (one serving per day)
Nutritional, hygienic and socio-economic dimensions of street foods in urban areas: the case of Nairobi
Get PDFExceptionally high rates of urbanisation in developing countries have been coupled with lack of employment and increasing urban poverty and undernutrition. Urban populations are thus utilising a variety of initiatives to enable them to survive. Street food vending is one such initiative. It is believed to have a double function in that it addresses the two increasing problems of urban poverty and undernutrition in developing countries. In Kenya, little information is available about street food vending. The sector is not officially permitted and vendors are often harassed. This study describes the scope of street food vending and buying in Nairobi and quality of street foods in terms of food group variety and energy and nutrient provision. It also assesses basic food hygiene knowledge and practice of vendors as well as the extent to which street foods are a source of livelihood for vending households.We found that street food vending in Nairobi is wide spread especially among the urban poor. Its growth reflects trends in economic and urban population growth. Although the sector offers products from all food groups, most vendors are one-food group sellers with cereals as the prominent group. In addition, major meal servings especially in working areas are able to provide more than adequate protein and iron, but their ability to provide adequate energy is limited. Meals are also poor in Vitamin A. However, where there is an income, particularly female vendors are able to sell foods of better nutritional quality than their male counterparts. Knowledge of general aspects of basic hygiene is well established while knowledge of specific issues is less spread among vendors. Nevertheless, vendors do not translate basic hygiene knowledge into safe food practices. Majority of vendors earns above the official minimum wage for Nairobi. For half of the vending households, street food vending is the main income provider. Such households are associated with the lowest socio-economic index and vendors as household heads. The vast majority of vending households feeds from the street food pot on a daily basis and obtains substantial amounts of the daily energy requirement.Therefore, street food vending (and consumption) is growing with increasing urban population. The foods, however, need improvement in terms of variety and nutrient harmonisation. Vendors are not completely ignorant of basic food hygiene practices but consumers probably do not demand safe food. Poverty and insecurity may also contribute to lack of investment of vendors into safe practices while absence of sanitation amenities at the vending sites makes it impossible to practice. Vending of street foods is a livelihood strategy for most vending households, hence banning it would strip them of a means of survival. What is needed is to officially recognise the sector, reconstruct and organise it with provision of sanitation amenities and put in place vendor training and consumer sensitisation programmes to ensure food safety and nutritional quality
Dietary non-nutrients and haemostasis in humans : effects of salicylates, flavonoids and ginger
No full textIn this thesis we studied the content of acetylsalicylate and total salicylates in foods, and we studied the effects of the dietary non-nutrients salicylates and flavonoids and of certain foods on haemostatic parameters in humans.Acetylsalicylic acid -aspirin- irreversibly inhibits platelet cyclo-oxygenase, leading to decreased platelet thromboxane A 2 production and decreased aggregation. Therefore it is effective as an anti-thrombotic drug in doses as low as 30 mg/d. Qualitative analyses by Swain et al suggested the presence of acetylsalicylate in foods. It was estimated that a normal mixed Western diet provides 10-200 mg/d of total salicylate and 3 mg/d of acetylsalicylate. We showed in 10 healthy subjects that 3 mg/d of acetylsalicylic acid decreased mean platelet thromboxane production by 39±8% (±sd). Thus, quantitative data on dietary acetylsalicylate deserved closer investigation. We determined acetylsalicylate and total salicylates in 30 foods using HPLC with fluorescence detection. Acetylsalicylate was lower than the detection limit (0.02 mg/kg for fresh and 0.2 mg/kg for dried products) in all foods. Total salicylates were 0-1 mg/kg in vegetables and fruits, and 3-28 mg/kg in herbs and spices. We showed that urinary excretion was a valid indicator for intake of pure (acetyl)salicylic acid (recovery 77-80%). We then studied urinary salicylate excretion in 17 subjects eating a variety of diets to estimate the content of bio-available salicylates of diets. Median excretion was 1.4 mg/24 h (range 0.8-1.6). Our data suggest that even purely vegetable diets provide less than 6 mg/d of salicylates, and no measurable acetylsalicylate. These amounts are probably too low to affect coronary heart disease risk, and worries about adverse effects of dietary salicylates on the behaviour of children may be unfounded.Others found that dietary flavonoids were associated with a reduced risk of coronary heart disease and stroke. This might be due to effects on haemostasis, because flavonoids have been reported to inhibit platelet aggregation in vitro . We found that concentrations of 2.5 μM of the flavone apigenin inhibited collagen- and ADP-induced platelet aggregation in vitro by about 26%, whereas the flavonols quercetin and quercetin-3-glucoside had no effect. No effects were found on platelet aggregation, thromboxane production, or other haemostatic parameters in 18 healthy subjects after they had consumed large amounts of quercetin- (onions) and apigenin-rich (parsley) foods daily for 7 d each. We conclude that claims for anti-aggregatory effects of flavonoids are based on the in vitro use of concentrations that cannot be attained in vivo . Our findings suggest that it is unlikely that reported effects of dietary flavonoids on coronary vascular disease risk are mediated through platelet aggregation or cyclo-oxygenase activity. Possible effects on known risk indicators for coronary heart disease from the coagulation cascade or the fibrinolytic system should be examined in a larger study.It has been claimed that ginger consumption exerts an anti-thrombotic effect by inhibiting platelet thromboxane production. We, however, found no effects on platelet thromboxane production in a placebo-controlled cross-over study in 18 healthy subjects after consumption of raw (-1±9%, mean±sd) or cooked ginger (1±8%).We conclude that contents of (acetyl)salicylate in foods are too low to affect disease risk. We could not confirm the putative anti-thrombotic effect of ginger, onions and parsley on haemostatic parameters in humans
Body composition and energy metabolism in elderly people
No full textThis thesis describes several studies related to the three components of energy balance in elderly people: body composition, energy expenditure, and energy intake.Body composition. The applicability of the body mass index, skinfold thickness method, and multi-frequency bioelectrical impedance was tested in elderly men and women. The first two methods predicted body fat in elderly people on a group level with a mean prediction error of 5%. The impedance method predicted total body water (at 50 kHz) and extra-cellular water (at 5 kHz) with a mean prediction error of 8-9%. Individual predictions should be interpreted carefully. Data from 2341 elderly men and women showed that smoking and physical inactivity were associated with a more abdominal fat distribution in men but not in women.Energy expenditure. To investigate the possible changes in energy expenditure with aging, energy expenditure at rest (RMR), after a meal of 1.3 MJ (DIT), and during physical activities was measured in elderly men and women and compared with values of young subjects. (RMR), was lower in elderly subjects, which could not be explained by differences in body composition or fat distribution. No relation between DIT and age 'per se' was observed. The energy costs of several physical activities, performed at a self- selected pace, were similar as compared to reference values based on young subjects.Energy intake. The reported energy and protein intake of elderly women, obtained by the dietary history method, was validated using measurements of total energy expenditure and urinary nitrogen excretion. An underestimation of 10-12% of the dietary intake was observed.These studies suggest that the decreasing energy requirement with aging is explained by a decrease in (RMR), DIT and possibly a lower physical activity level. The decrease is partly explained by changes in body composition
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