Why do women of low socioeconomic status have poorer dietary behaviours than women of higher socioeconomic status? A qualitative exploration

In developed countries, persons of low socioeconomic status (SES) are generally less likely to consume diets consistent with dietary guidelines. Little is known about the mechanisms that underlie SES differences in eating behaviours. Since women are often responsible for dietary choices within households, this qualitative study investigated factors that may contribute to socioeconomic inequalities in dietary behaviour among women. Semi-structured interviews were conducted with 19 high-, 19 mid- and 18 low- SES women, recruited from Melbourne, Australia, using an area-level indicator of SES. An ecological framework, in which individual, social and environmental level influences on diet were considered, was used to guide the development of interview questions and interpretation of the data. Thematic analysis was undertaken to identify the main themes emerging from the data. Several key influences varied by SES. These included food-related values such as health consciousness, and a lack of time due to family commitments (more salient among higher SES women), as well as perceived high cost of healthy eating and lack of time due to work commitments (more important for low SES women). Reported availability of and access to good quality healthy foods did not differ strikingly across SES groups. Public health strategies aimed at reducing SES inequalities in diet might focus on promoting healthy diets that are low cost, as well as promoting time-efficient food preparation strategies for all women.

Dietary intake measurements

To provide a concise summary of field and laboratory methods for the measurement of dietary intake with particular reference to the assessment of energy and protein intake and to the pitfalls and difficulties that may be encountered in practice when implementing the methods both in the field and under laboratory conditions.

Variation in the fatty acid composition of the blubber in Cape fur seals (Arctocephalus pusillus pusillus) and the implications for dietary interpretation

Analysis of the fatty acid (FA) composition of blubber is a valuable tool in interpreting the diet of marine mammals. This technique is based on the principle that particular FA present in prey can be incorporated largely untransformed into predator adipose tissue stores, thereby providing biochemical signatures with which to identify prey species. Several studies of phocid seals and cetaceans have documented vertical stratification in the FA composition of blubber such that inferences about diet may vary greatly depending on the layer of the blubber that is analysed. It is not known whether blubber in otariid seals (fur seals and sea lions) also displays vertical stratification in FA composition. Furthermore, it is not known whether the FA composition of blubber is uniform in these species. In the present study, the vertical and regional variation in FA composition of blubber was investigated in seven adult female Cape fur seals (Arctocephalus pusillus pusillus). The proportion of monounsaturated fatty acids (MUFA) was greater in the outer (43.6±1.3%) than inner portion (40.9±1.2%; t20=5.59, P<0.001) whereas the proportions were greater in the inner than outer portions for saturated fatty acids (23.6±0.5% and 21.9±0.6%, respectively, t20 = 5.31, P<0.001) and polyunsaturated fatty acids (PUFA, 35.5±0.7% and 34.5±0.7%, respectively, t20 = 3.81, P < 0.001). There was an inverse relationship between MUFA and PUFA in the blubber, independent of sampling location. In addition, with the exception of the inner portion from non-lactating females, blubber from the mammary area had the highest proportions of 18:1ω9c and total MUFA, followed by blubber from the rump and neck, suggesting that the deposition and mobilisation of blubber lipids may not be uniform around the body in otariid seals. These results support the need for blubber tissue to be sampled from the same site on animals, and to the full depth of the blubber layer, to minimise variation in FA profiles that could occur if different sites and depths were sampled. Such standardisation of sampling will further aid in interpreting diet in otariid seals using the FA Signature Analysis approach.

Food, health, the environment and consumers' dietary choices

The aim of this paper is to examine some of the issues that surround food and the environment, particularly conventional and organic agriculture and food distribution, and to look at some of the health implications. It is argued that the links between food, health and the environment are strong. Consumers have the power to have an impact positively or negatively on the environment via their dietary choices. By providing information and advice about the environmental as well as the health impact of food choices, health and nutrition professionals could increase consumers' awareness of such issues.

Effects of dietary oil source on growth and fillet fatty Acid composition of Murray cod, Maccullochella peelii peelii

The Murray cod, an Australian native freshwater fish, supports a relatively small but increasing aquaculture industry in Australia. Presently, there are no dedicated commercial diets available for Murray cod; instead, nutritionally sub-standard feeds formulated for other species are commonly used. The aim of the present investigation was to assess the suitability of two plant based lipid sources, canola oil (CO) and linseed oil (LO), as alternatives to fish oil for juvenile Murray cod. Five iso-nitrogenous, iso-calorific, iso-lipidic semi-purified experimental diets were formulated with 17% lipid originating from 100% cod liver oil (FO), 100% canola oil, 100% linseed oil and 1 : 1 blends of canola and cod liver oil (CFO) and 1 : 1 blends of linseed and cod liver oil (LFO). Each of the diets was fed to apparent satiation twice daily to triplicate groups of 50 Murray cod with initial mean weights of 6.45 ± 1.59 g for 84 days at 22 °C. Final mean weight, specific growth rate and daily feed consumption were significantly higher for the FO and LFO treatments compared to the LO treatment. Feed conversion and protein efficiency ratios were not significantly different amongst treatments. Experimental diets containing vegetable oil and vegetable oil blend(s) had significantly higher concentrations of n-6 fatty acids, predominantly in the form of linoleic acid (LA), while n-3 fatty acids were present in significantly higher concentrations in LO and LFO treatments. The fatty acid composition of Murray cod fillet was reflective of the dietary lipid source. Fillet of fish fed the FO was highest in EPA (20:5n-3), ArA (20:4n-6) and DHA (22:6n-3). Fish fed the CO diet had high concentrations of oleic acid (OlA) (192.2 ± 10.5 mg g lipid− 1), while the fillet of Murray cod fed the LO diet was high in α-linolenic acid (LnA) (107.1 ± 6.7 mg g lipid− 1). The present study suggests that fish oil can be replaced by up to 100% with canola oil and by up to 50% with linseed oil in Murray cod diets with no significant effect on growth.

Family food environment and dietary behaviors likely to promote fatness in 5-6 year-old children

Background: The family food environment (FFE) is likely to exert important influences on young children's eating. Examination of multiple aspects of the FFE may provide useful insights regarding which of these might most effectively be targeted to prevent childhood obesity.

Objective: To assess the associations between the FFE and a range of obesity-promoting dietary behaviors in 5–6-year-old children.

Design: Cross-sectional study.

Subjects: Five hundred and sixty families sampled from three socio-economically distinct areas.

Measurements: Predictors included parental perceptions of their child's diet, food availability, child feeding practices, parental modeling of eating and food preparation and television (TV) exposure. Dietary outcomes included energy intake, vegetable, sweet snack, savory snack and high-energy (non-dairy) fluid consumption.

Results: Multiple linear regression analyses, adjusted for all other predictor variables and maternal education, showed that several aspects of the FFE were associated with dietary outcomes likely to promote fatness in 5–6-year-old children. For example, increased TV viewing time was associated with increased index of energy intake, increased sweet snack and high-energy drink consumption, and deceased vegetable intake. In addition, parent's increased confidence in the adequacy of their child's diet was associated with increased consumption of sweet and savory snacks and decreased vegetable consumption. 

Conclusion:  This study substantially extends previous research in the area, providing important insights with which to guide family-based obesity prevention strategies.

Dietary intake in post-menopausal women

Si has been suggested as an essential element, and may be important in optimal bone, skin and cardiovascular health. However, there are few estimates of dietary Si intakes in man, especially in a UK population. Following the development of a UK food composition database for Si, the aim of the present study was to investigate dietary intakes of Si amongst healthy women aged over 60 years and to identify important food sources of Si in their diet. Healthy, post-menopausal female subjects (>60 years of age; n 209) were recruited from the general population around Dundee, Scotland as part of an unrelated randomised controlled intervention study where dietary intake was assessed using a self-administered, semi-quantitative food-frequency questionnaire at five time-points over a 2-year period. Food composition data on the Si content of UK foods was used to determine the Si content of food items on the food-frequency questionnaire. Mean Si intake was 18·6 (sd 4·6) mg and did not vary significantly across the 2 years of investigation. Cereals provided the greatest amount of Si in the diet (about 30%), followed by fruit, beverages (hot, cold and alcoholic beverages combined) and vegetables; together these foods provided over 75% about Si intake. Si intakes in the UK appear consistent with those reported previously for elderly women in Western populations, but lower than those reported for younger women or for men.

Role of dietary factors in the development of basal cell cancer and squamous cell cancer of the skin

The role of dietary factors in the development of skin cancer has been investigated for many years; however, the results of epidemiologic studies have not been systematically reviewed. This article reviews human studies of basal cell cancer (BCC) and squamous cell cancer (SCC) and includes all studies identified in the published scientific literature investigating dietary exposure to fats, retinol, carotenoids, vitamin E, vitamin C, and selenium. A total of 26 studies were critically reviewed according to study design and quality of the epidemiologic evidence. Overall, the evidence suggests a positive relationship between fat intake and BCC and SCC, an inconsistent association for retinol, and little relation between ß-carotene and BCC or SCC development. There is insufficient evidence on which to make a judgment about an association of other carotenoids with skin cancer. The evidence for associations between vitamin E, vitamin C, and selenium and both BCC and SCC is weak. Many of the existing studies contain limitations, however, and further well-designed and implemented studies are required to clarify the role of diet in skin cancer. Additionally, the role of other dietary factors, such as flavonoids and other polyphenols, which have been implicated in skin cancer development in animal models, needs to be investigated.

Development of a food composition database for the estimation of dietary intakes of glucosinolates, the biologically active constituents of cruciferous vegetables

Evidence indicates that cruciferous vegetables are protective against a range of cancers with glucosinolates and their breakdown products considered the biologically active constituents. To date, epidemiological studies have not investigated the intakes of these constituents due to a lack of food composition databases. The aim of the present study was to develop a database for the glucosinolate content of cruciferous vegetables that can be used to quantify dietary exposure for use in epidemiological studies of diet–disease relationships. Published food composition data sources for the glucosinolate content of cruciferous vegetables were identified and assessed for data quality using established criteria. Adequate data for the total glucosinolate content were available from eighteen published studies providing 140 estimates for forty-two items. The highest glucosinolate values were for cress (389 mg/100 g) while the lowest values were for Pe-tsai chinese cabbage (20 mg/100 g). There is considerable variation in the values reported for the same vegetable by different studies, with a median difference between the minimum and maximum values of 5·8-fold. Limited analysis of cooked cruciferous vegetables has been conducted; however, the available data show that average losses during cooking are approximately 36 %. This is the first attempt to collate the available literature on the glucosinolate content of cruciferous vegetables. These data will allow quantification of intakes of the glucosinolates, which can be used in epidemiological studies to investigate the role of cruciferous vegetables in cancer aetiology and prevention.

Comparability of dietary patterns assessed by multiple dietary assessment methods: results from the 1946 British Cohort

Objective: The aim of this study is to evaluate the consistency of dietary patterns assessed through the use of a dietary recall and a 5-day food diary. Design: Participants (n=2265) of a longitudinal study of health and development completed 48-h dietary recall at interview, followed by a 5-day food diary and with the 24 h immediately preceding the interview analysed separately as a 24-h recall. Mean intakes of foods and nutrients were calculated and dietary patterns were assessed using exploratory factor analysis, using the method of principal components. Paired t-tests and correlation coefficients were used to compare the three dietary assessment methods. Results: Five distinct dietary patterns were identified using the food diary and the 48-h recall but were less consistent on the 24-h recall.  Correlations between factor scores on the 48-h recall and the food diary (r=0.13–0.67) were higher than those between the 24-h recall and food diary (r=-0.01–0.59). The recall methods were effective at ranking subjects according to food and nutrient intakes, with the 48-h recall and food diary showing higher correlations in both males and females. Conclusions: This study indicates that a 48-h recall effectively characterises dietary patterns in British adults when compared to a food diary and ranks participants appropriately with respect to most nutrients and foods and is superior to a single 24-h recall. These results have implications for longitudinal studies where maximising response rates to repeat dietary assessment tools is essential.

Effects of dietary lipid sources on flavour volatile compounds of brown trout (Salmo trutta L.) fillet

The high cost and unpredictable availability of fish meal and fish oil (FO) forced feed mill companies to look for alternative ingredients for aquafeeds. In this study, the effects of alternative dietary lipid sources [FO as control, canola oil (CO), oleine oil (OO), poultry fat (PF) and pork lard (PL)] in trout feed on flavour volatile compounds occurring in brown trout (Salmo trutta L.) fillet were evaluated after 70 days of feeding (rearing temperature 14.6°C). Total amounts of volatile compounds identified were higher for fillets of fish fed diets containing only FO as lipid sources. Total amount of alcohols and aldehydes of the fillets were linearly directly related to the percentage content of polyunsaturated fatty acids (PUFA) n-3 of brown trout flesh. The use of alternative dietary lipid sources, modifying the fillet fatty acids composition, affect the total amount of volatile compounds and, changing the relative amount of each volatile compound, affect the flavour of the fish flesh.

Effects of alternative dietary lipid sources on performance, tissues chemical composition, mitochondrial fatty acid oxidation capabilities, and sensory characteristics in brown trout (Salmo trutta L.)

The efficiency of five dietary lipid sources (fish oil as control—C; canola oil—CO; poultry fat—PF; pork lard—PL; and oleine oil—OO) were evaluated in juvenile brown trout (58.4±0.7 g) in an experiment conducted over 70 days at 14.6±0.4 °C. The best growth was observed in fish fed the C diet whereas the PL diet fed fish had the best feed utilization. Significant differences in carcass and muscle proximate composition, but not in liver, were noted among fish fed the different dietary treatments. The fatty acid composition of muscle largely reflected that of the diets, while total cholesterol was not affected. The atherogenicity and the thrombogenicity qualities of the trout flesh were modified by the lipid sources. Sensory analysis did not show any significant differences among the cooked fillets with respect to dietary treatments, while in uncooked products, some significant differences were observed. The carnitine palmitoyltransferase I and II (CPT-I and CPT-II) activities of liver and white muscle were assayed for a better understanding of the potential β-oxidation capability of the different dietary lipid sources. The hepatic, but not white muscle CPT-I and CPT-II activities were affected by dietary treatments. This study showed that alternative lipid sources could be used effectively for oil coating extruded diets for brown trout.

Dietary composition of pregnant women is related to size of the baby at birth

The fetal origins theory of adult disease suggests that term infants who are small for their gestational age have an increased susceptibility to chronic disease in adulthood as a consequence of physiologic adaptations to undernutrition during fetal life. Consistent evidence for an influence of women's dietary composition during pregnancy on growth of their babies is lacking, despite robust effects in animal experiments. We undertook a prospective observational study of 557 women aged 18-41 y, living in Adelaide, South Australia. Diet was assessed in early and late pregnancy using an FFQ. In early pregnancy, medians for energy intake, the proportion of energy derived from protein and from carbohydrate were 9.0 MJ, 17 and 48%, respectively. In late pregnancy the corresponding medians were 9.2 MJ, 16 and 49%. In early pregnancy, the percentage of energy derived from protein was positively associated with birth weight (P = 0.02) and placental weight (P = 0.07), independently of energy intake and weight gain during pregnancy, and after adjustment for potential confounders, including maternal age, parity, and smoking. Effects were stronger among women (n = 429) who had reliable data, based on prespecified criteria including the plausibility of dietary data when referenced against estimated energy expenditure. In addition, for this subgroup, the percentage of energy from carbohydrate in early and late pregnancy was negatively associated with ponderal index of the baby, and a specific effect of protein from dairy sources was identified. These data support the proposition that maternal dietary composition has an effect on fetal growth. Maternal diet in Western societies may therefore be important for the long-term health of the child.

Dietary counseling to increase natural folate intake: a ransomized placebo-controlled trial in free-living subjects to assess effects on serum folate and plasma total homocysteine.

BACKGROUND: The association between vascular disease and elevated plasma total homocysteine (tHcy) concentrations is caused, in part, by inadequate intakes of dietary folate. Increasing folate intake either through supplements or foods naturally rich in folates has been shown to decrease tHcy concentrations. OBJECTIVE: The aim of this study was to determine whether a similar reduction in tHcy was possible in free-living persons receiving dietary counseling. DESIGN: The study included a 4-wk placebo-controlled dietary intervention trial in which participants consumed either unfortified breakfast cereal (control group) or an extra 350 micro g folate derived from food/d (dietary group). Serum folate and tHcy concentrations in both groups were measured before and after the intervention period, and the concentrations in the dietary group were also measured 17 wk after the intervention period. RESULTS: During the 4-wk intervention, mean dietary folate intake in the dietary group increased from 263 (95% CI: 225, 307) to 618 micro g/d (535, 714), resulting in a mean increase in serum folate of 37% (15%, 63%) and a decrease in tHcy from 12.0 (10.9, 13.3) to 11.3 micro mol/L (10.2, 12.5). A further decrease in tHcy occurred in the dietary group during follow-up, with a final tHcy concentration of 9.7 micro mol/L (8.8, 10.8). CONCLUSIONS: Increasing natural folate intake improved folate status and decreased tHcy concentrations to an extent that may significantly reduce the risk of vascular disease. Dietary modification may have advantages over folic acid fortification because the altered food-consumption patterns lead to increased intakes of several vitamins and minerals and decreased intakes of saturated fatty acids.