Diet, prolactin, and breast cancer.

Relationships between dietary nutrients and plasma prolactin concentration were studied in 249 women with a history of nonskin cancers among first-degree female relatives. For each quintile of nutrient density, the odds ratio (OR), relative to the lowest quintile, of having an elevated (above the median) prolactin concentration was estimated by logistic regression, taking into account parity, menopausal status, and current tobacco-smoking habits. For nutrient densities estimated from 24-h recall data there was a significant positive association between plasma prolactin concentration and increasing saturated fatty acid intake; the OR of elevated prolactin in the top quintile was 3.1 [95% confidence interval (CI) 1.2-8.1] and there was a negative association with vitamin C [OR in the top quintile 0.28, (95% CI 0.10-0.78)]. For usual nutrient densities (estimated by quantitative food frequency questionnaire) there was a statistically significant trend (P = 0.04) toward lower prolactin concentrations with increasing sodium density, and a marginally significant positive trend (P = 0.07) with increasing dietary density of refined sugars.

Public health implications of dietary differences between social status and occupational category groups.

STUDY OBJECTIVE: As there is a social status gradient in chronic disease mortality in Australia, this study aimed to establish whether there were substantial differences among socioeconomically defined groups with respect to food choice and nutrient intake, in the context of risk of nutrition related chronic diseases. DESIGN AND PARTICIPANTS: Cross sectional data were collected from a randomly selected population sample of 1500 urban Australian adults. Data were collected by postal questionnaire, which included an assessment of dietary intake and questions on sociodemographic details. Three measures of social position were collected: occupation, educational status, and income status. Occupation was interpreted both on a continuous, prestige scale, and also as categorical occupational groupings. MAIN RESULTS: The study achieved a 70% response rate. Higher social status was generally associated with healthier dietary intakes, with lower fat and refined sugar densities, and higher fibre densities, but also with higher alcohol density. No differences were found in salt, polyunsaturated fat, protein, or complex carbohydrate densities across groups. Food intake differences were also found between occupational status groups, with the upper social groups tending to consume more wholegrain cereal foods, low fat milk, and fruit, and less refined cereal foods, full cream milk, fried meat, meat products, and discretionary sugar; but also more cheese and meat dishes. CONCLUSIONS: Although this study did show statistically significant differences across social status groups in relation to nutrient and food intakes, these differences were small compared to the disparity between intakes of all groups and the recommended patterns of intake, and did not appear to be great enough to be a major explanatory variable in differences in disease risk across groups.

Public perceptions of the role of dietary and other environmental factors in cancer causation or prevention.

STUDY OBJECTIVE: The aim was to establish the public's perception of the relative importance of various environmental risk factors for cancer. DESIGN: A postal survey was undertaken using a questionnaire to assess the public's knowledge of cancer morbidity and mortality and the role of lifestyle and genetic risk factors. Sociodemographic data were also collected. SETTING: The survey was completed in the state of South Australia. PARTICIPANTS: A random sample of 1500 names were selected from the electoral rolls of the state. These rolls contain the names of all Australian citizens over the age of 18 years. A response rate of 73% was achieved. MEASUREMENTS AND MAIN RESULTS: The results of the survey showed that the knowledge base of the community was generally high, with few differences across sociodemographic groups. The relative importance of cancer as a contributor to mortality was, however, overestimated and the potential for "cure" underestimated. The role of both diet and cigarette smoking in cancer promotion was widely recognised but there was an overemphasis on the importance of pollution of the food supply compared to imbalance of nutrients. Respondents were more able to assign risk in relation to diet using a food based assessment, compared to a nutrient approach. There was wide acceptability that lifestyle change could have a profound effect on the cancer profile of the community. CONCLUSIONS: With the relatively high degree of awareness and acceptance of lifestyle factors as cancer risk determinants, campaigns which involve skill transfer and removal of barriers to change would appear to be the most relevant approach to improvement in community behaviour.

Demographic and dietary profiles of high and low fat consumers in Australia.

STUDY OBJECTIVE: To determine the socio-demographic, attitudinal, and dietary correlates of high and low fat consumption in the community. DESIGN: The study was undertaken using a postal survey format. A questionnaire was sent for self completion to a randomised sample of the adult population of two Australian states. PARTICIPANTS: Adult participants were selected randomly from the Electoral Rolls of the states of Victoria and South Australia. As voting at elections is compulsory in Australia, these rolls contain the names of all Australian citizens over the age of 18 years. Altogether 3209 respondents completed the survey giving a response rate of 67%. MAIN RESULTS: Lower than average fat consumption was more common in women. Age was a significant factor only in men. Occupation was not related to lower than average fat consumption but manual work and low occupational prestige were linked to higher than average consumption in men. People with a history of conditions related to heart disease were more likely to be low consumers but medical history did not distinguish high from average consumers. Low fat consumption was linked to higher refined and natural sugar consumption and higher alcohol consumption, but protein and complex carbohydrate consumption did not vary with fat consumption. Low fat diets also had higher densities of fibre and most vitamins and minerals, the exceptions being retinol, zinc, and vitamin B12, nutrients generally linked to meat and dairy consumption. Of the latter, only the low zinc concentrations, which are already borderline in the community, pose a potential nutritional problem. CONCLUSIONS: This study showed very strong links between dietary fat intake and the intake of nearly all other nutrients in the diet. The results highlight the need to consider relationships between nutrients not only for purposes of nutrition education but also in relation to nutritional epidemiology studies.

Food consumption patterns in an affluent society and barriers to overcoming dietary change.

In affluent nations, there has been an increasing awareness of the links between diet and the incidence of chronic diseases such as heart disease, hypertension and cancer. In some of these countries, this has led to improvements in the dietary profiles of the community and its health-related status. Studies of random samples of the Australian population carried out in the last decade or so have shown a downward trend in the consumption of total and saturated fats and salt and an increase in polyunsaturated fat and fibre. However, detailed assessment of food consumption patterns reveal that the changes in dietary patterns relate predominantly to improvement in choice within food categories rather than a fundamental change in the relative amounts of foods consumed across categories such as meats, dairy foods, cereal grains and fruits and vegetables. The surveys show that knowledge about the links between diet and disease is encouragingly high in most sectors of the Australian community as is concern about the healthiness of the food supply but time constraints, the perception that "healthy" foods are boring foods, lack of information on packaging and family pressures were seen as major barriers to dietary change. A further barrier is lack of knowledge about the balance of foods required and in particular, the value of cereal foods. Analysis of the dietary data show that further significant improvements in the dietary profile are only likely to accrue from a fundamental change in the relative use of the major food categories.

The vitamin and mineral intake of a free-living young elderly Australian population in relation to total diet and supplementation practices.

Although there have been several studies of the nutritional intake and status of elderly sections of industrialized countries such as Britain, the United States and Australia, most of these studies relate to institutionalized elderly or those receiving social support such as meals-on-wheels. The study reported here presents the results of a dietary survey of a randomly selected group of free-living younger elderly residents of Adelaide, Australia. Mean intakes for most nutrients were equal to or above the recommended intakes. The proportion of subjects 'at risk' was not as high as reported for less able elderly groups but the nutrients 'at risk' were similar, namely: folate, calcium, vitamin B6, zinc, magnesium and copper. Comparisons with the results of two other random surveys of free-living elderly residents of Boston and Gothenburg showed some variation in total intakes especially amongst women but many similarities in the patterns of nutrient density and nutrients 'at risk'.

Alcohol consumption and blood pressure in a group of young Australian males.

Several studies have suggested that regular consumption of alcoholic beverages is associated with hypertension. Recent studies, however, have implied tht whilst moderate or high ingestion of alcohol may be detrimental, a threshold exists for alcohol consumption below which alcohol may even exert a beneficial effect. As part of a larger study of a male, service population (average age 23 years) undergoing an initial training course of ten weeks duration, we measured both blood pressure and alcohol consumption in 350 men at entry and/or exit from the course. Alcohol intake was assessed using a supervised, self-administered dietary questionnaire which included two pre-tested measures of alcohol consumption. High alcohol consumption in these young men was not related to elevated systolic or diastolic blood pressure; neither was the recently reported lowering of blood pressure in low alcohol consumers compared to non-drinkers, apparent in this young population. The lack of relationship between alcohol consumption and blood pressure in this predominantly young group suggests that the relationship, if there is one, between these two factors only becomes clinically obvious either with longer exposure to alcohol, or in an older age group in whom the mechanism of control of blood pressure may already be somewhat compromised by other age-related physiological changes which are not readily measurable.

Nutritional profile of recruits to a fitness programme.

Examination of the dietary habits of a group of adults embarking on a two-year fitness programme (the "Adelaide 1000") showed that, although many of their dietary habits were more consistent with national dietary guidelines than those of a comparison community group, their overall intake of nutrients was similar. The major difference was a substantially higher rate of dietary supplementation with vitamin and mineral preparations in the fitness group. The implications of these findings are discussed in relation to public understanding of dietary principles and to the provision of practical nutritional guidance in conjunction with fitness programmes.

Dietary behaviours of volunteers for a nutrition education program, compared with a population sample.

The dietary behaviours of and recent dietary change by volunteers for a nutrition education program were compared with those of a more population-representative sample. The population sample was randomly selected from the electoral rolls of three Australian cities. Those selected received questionnaires which were to be completed and returned by mail. The sample of volunteers was recruited from the electoral rolls of suburbs of either high or low social status in one of these cities. Volunteers were posted a questionnaire, to be returned in person. A quantified food frequency questionnaire was used to estimate relative intake of 19 nutrients, plus energy intake. Occupation, age, sex, reported recent dietary change and diet-related beliefs were also assessed. The population sample was weighted to the age and occupational distribution of the education program sample. Compared to the 874 respondents in the population sample (70.4 per cent response rate), the 487 volunteers (24.2 per cent response rate) for the nutrition education program had healthier nutrient intakes and reported more dietary behaviour changes. Recruitment in the education program was greater in areas of higher social status (32 per cent) than in areas of lower social status (20 per cent). The potential effect of such a program on the whole population was demonstrated by the proportions that volunteered and the characteristics of these volunteers. The need to provide a range of opportunities for changing dietary behaviour, according to the health-related behaviours and beliefs of target groups and their socio-economic circumstances, was highlighted.

Social desirability response bias and dietary inventory responses.

Royal Australian Air Force recruits completed a dietary frequency inventory (n = 309), a short social desirability inventory phrased in dietary terms (SDF, n = 309), and, in addition, a subsample answered the Marlow-Crowne social desirability scale (n = 96). Correlational and factor analyses showed that the SDF scores were related to the MC scale; and, the scores on the SDF scale were significantly related to the reported consumption of fresh fruit and vegetables and snack foods. In a further study, 20 lay persons were asked to sort the 66 foods listed in the dietary inventory into three categories: nutritionist-approved foods; nutritionist-disapproved foods; and, an 'uncertain' category. The results confirmed the finding that fresh fruit and vegetables were socially desirable foods, but sweet foods were not. It is concluded that social approval needs may influence the manner in which individuals report their consumption of these foods.

Foetal brain development in the sheep.

The pattern of normal foetal brain development has been described for the Merino sheep. Controlled flock matings were used and foetuses removed by hysterotomy at 40, 54, 67, 81, 90, 95, 109, 121 and 150 days of gestation. Lambs at 7 days after birth and adults were also studied. The CNS was dissected, separated and weighed as four segments--cerebral hemispheres, brain stem, cerebellum and spinal cord. Determinations of DNA, RNA, protein, cholesterol and water content were subsequently carried out on each segment. Brain weight increased from 0.264 g (40 days) to 52.74 g at 150 days. The ratio to body weight decreased from 6.7% (40 days) to 1.5% (150 days). DNA increased more rapidly from 40 to 90 days in the cerebral hemispheres and brain stem than in the cerebellum and spinal cord and this increase preceded the main increase in weight. Increases in cholesterol and decreases in water content were also more marked in the cerebral hemispheres and brain stem. Increase in brain weight occurred in two phases, one up to 90 days followed by a more rapid and larger increase after 90 days which continued to birth. These two phases appear to reflect an increase in neuroblast multiplication followed by neuroglial multiplication and myelination respectively. At birth, brain weight had reached 50% of adult size, the cerebral hemispheres 52% of adult size, the cerebellum 40% and spinal cord 40%. The relative maturity of the brain at birth justifies the classification of the sheep as a prenatal brain developer.

The Victorian Nutrition Survey--intakes and sources of dietary fats and cholesterol in the Victorian population.

A random State-wide nutrition survey of the population of Victoria that was carried out in late 1985 demonstrated that the total fat and saturated fat intake of Australians had changed little since studies that were carried out in the 1970s. However, since that time, there has been a considerable increase in the contribution of polyunsaturated fats with a consequent improvement in the polyunsaturated-to-saturated fatty-acid ratio in the diet. The survey was carried out by means of a postal technique and a semiquantified food-frequency questionnaire which allows for the characterization of usual dietary intake in individuals. The survey served to highlight the value of collecting nutrient, food and food-habits data in the same individuals and demonstrated that relatively cost-effective surveys of this type make feasible the regular continuing surveillance of the usual nutrient intakes of large numbers of individuals.

Diet, other lifestyle factors and HDL cholesterol in a population of Australian male service recruits.

The association between dietary and other factors and plasma high density lipoprotein (HDL) cholesterol concentration was examined cross-sectionally and longitudinally in a sample (n = 530) of Australian male service recruits (mean age 21 years) involved in a nine-week induction training program. The findings suggest that diet may make an independent contribution to HDL cholesterol, equal in importance to alcohol, smoking, fitness and obesity--previously identified as being important. Water and carbohydrate consumption showed a negative cross-sectional association with HDL cholesterol on multivariate analysis. The negative association for carbohydrates was also observed longitudinally. Less consistent associations for saturated fat and for total energy intake were also observed. When the relationship between dietary factors and the HDL cholesterol/cholesterol ratio was examined the most important dietary factor appeared to be saturated fat, which was negatively associated with this ratio. No consistent association was observed for any of the 67 individual foods examined.

Foetal thyroidectomy and brain development in the sheep.

Sheep foetuses were surgically thyroidectomized at 50-60 days gestation, when thyroid function begins, and the pregnancy was then allowed to continue until 90, 120 or 150 days (term). At these times the foetuses were removed by caesarean delivery, exsanguinated, weighed and dissected. The central nervous system was divided--cerebral hemispheres, brain stem, cerebellum and spinal cord for subsequent analysis. Comparison was made with sham operations on seven foetuses. Thyroidectomy led to a fall in body weight (24.7%) and brain weight (11.7%) at 120 days and 150 days, 31.1% and 24.5% respectively. The hemispheres showed the greatest change and the cerebellum the least. DNA and protein contents were reduced in the hemispheres and cerebellum at 150 days, while in the brain stem and spinal cord the DNA content was not significantly affected. Protein content was, however, reduced indicating a reduced cell size, but not a reduced cell number as in the other two regions. Somatic changes included reduced wool growth, delayed osseous development in the limbs (X-ray assessment) a reduced heart weight (39.1%) and an increased pituitary weight (48.1%). The thyroidectomized lambs failed to survive for more than a few hours after birth or caesarean delivery at 150 days. The findings indicate significant effects of foetal thyroidectomy on brain development in the sheep late in pregnancy along with other evidence of foetal hypothyroidism.

Sociodemographic determinants in Australia of the intake of food and nutrients implicated in cancer aetiology.

In recent years, there has been a growing awareness of the role that diet can play in the promotion, retardation or amelioration of the cancer process. This has led to the development of dietary guidelines for cancer prevention by health authorities in several Western societies. However, there is still limited information about the sociodemographic determinants of intake of foods and nutrients of interest in many of these countries. A study of the dietary intake of a random sample of residents of the State of Victoria in Australia showed that women, those in the older age groups and in the higher occupational ranks, had diets more in line with current recommendations for cancer prevention--the most marked differences being between men and women. However, the sociodemographic differences were relatively small compared with the low rate of overall compliance with the guidelines.

Intakes and sources of a range of dietary sugars in various Australian populations.

Data from the Apparent Consumption of Foodstuffs publications of the Australian Bureau of Statistics have, until recently, been the major source of information in Australia about the consumption of refined sugars. This database, which relies on national figures for production, importation, export, storage and stocks, and on population statistics, had indicated that some 14% of the total energy that was available in Australia was derived from refined sugars. Similar figures have been derived for both the United States and United Kingdom by means of this kind of national food-availability database. However, a recent reanalysis of a large-scale dietary survey of individuals in the United States has indicated a much lower level of consumption of refined sugars. In recent years, several large-scale surveys of individuals' consumption patterns in the Australian population have been carried out by the Social Nutrition Program at the CSIRO Division of Human Nutrition. These surveys indicate that the mean level of consumption of refined sugars is not as high as that which previously was estimated from Apparent Consumption data. However, there was a wide range of intakes and a substantial proportion of individuals with intakes that were above recommended levels.

A case-control study of diet and cancer of the pancreas.

In a population-based case-control study carried out in Adelaide, South Australia, during the years 1984-1987, the diets of 104 cases of cancer of the pancreas 1 year prior to diagnosis were compared with the diets of 253 community controls. A quantitative food-frequency questionnaire was used to assess usual dietary intakes of 179 food items. Cases were compared with controls in terms of both the amounts of individual food items consumed and the estimated contributions of 48 nutrients to the diet. Food items consumed more by cases than controls included boiled eggs and omelettes as well as a number of items that could be collectively described as sweet and fatty. Food items consumed less by cases than controls included several vegetables and fruits. Conditional logistic regression analysis of nutrient intake adjusted for total energy and for alcohol and tobacco usage yielded an estimate of relative risk of 3.19, with a 95% confidence interval of 1.58-6.47 for the highest quartile of cholesterol intake (relative to the lowest quartile). For the top quartile of refined sugar intake, the estimated relative risk was 2.21 (95% confidence interval 1.07-4.55). Several nutrients derived principally from plant foods were statistically significantly associated with lower risks. Alcohol consumption was significantly lower among cases than controls. Current smokers had a relative risk of 1.76 (95% confidence interval 0.93-3.34) relative to those who had never smoked. There was no association of pancreatic cancer with coffee drinking.