Dietary patterns and diet quality : approaches to assessing complex exposures in nutrition

Dietary pattern analysis provides a practical way to characterise total diet. In contrast to single food approaches, measures of dietary patterns capture interactions between food components and assist in the development of food guidelines from a public health perspective. Two main approaches to assessing dietary patterns, multivariate statistical approach and dietary indices or scores in epidemiological studies, are assessed.

Is dietary management a responsibility of general practitioners? The views of Victorian general practitioners

Rationale : Australia is experiencing an evolving healthcare system, resulting in an aim of systematic managed care for patients with chronic disease. One outcome has been debate on doctors' dietary management responsibilities.
Aim : To identify general practitioners' perceptions of their dietary management responsibilities for adult cardiac patients.
Methods : A Two phase study was conducted. First, semi-structured interviews with 30 Melbourne general practitioners were conducted to gather preliminary information about dietary management. The results informed a questionnaire for the second phase. This was completed by 248 general practitioners (30%) in Victoria.
Principal findings : Themes arising in interviews, and also supported by cross-sectional survey showed that doctors perceive themselves as filling one or more of three roles. The majority (87.4%) endorsed an 'Influencing' role, 27.4% endorsed 'Dietary Educator' and 44.0% a 'Coordinator' role. The Influencer role was characterised by encouragement of dietary behaviour change, such as discussing benefits and consequences of inaction to dietary change. The Educator role was characterised by the provision of a range of behaviour change strategies- 'how to' achieve change. 'Coordinators' reported the provision of dietary counselling belonged to dietitians alone.
Implications : The results indicate doctors' awareness of need for patients' dietary education should be increased. This could be accomplished by one-on-one education. Patients' access to dietary education should also be facilitated by doctors' referring on. Embedding dietary management protocols in doctors' managed care templates could improve patients' access to dietary education and enhance doctor's collaborative roles.
Presentation type : Paper
Session theme : Getting Evidence into Practice 2

Arterial compliance in obese subjects is improved with dietary plant n-3 fatty acid from flaxseed oil despite increased LDL oxidizability

The compliance or elasticity of the arterial system, an important index of circulatory function, diminishes with increasing cardiovascular risk. Conversely, systemic arterial compliance improves through eating of fish and fish oil. We therefore tested the value of high intake of alpha-linolenic acid, the plant precursor of fish fatty acids. Fifteen obese people with markers for insulin resistance ate in turn four diets of 4 weeks each: saturated/high fat (SHF), alpha-linolenic acid/low fat (ALF), oleic/low fat (OLF), and SHF. Daily intake of alpha-linolenic acid was 20 g from margarine products based on flax oil. Systemic arterial compliance was calculated from aortic flow velocity and aortic root driving pressure. Plasma lipids, glucose tolerance, and in vitro LDL oxidizability were also measured. Systemic arterial compliance during the first and last SHF periods was 0.42 +/- 0.12 (mean +/- SD) and 0.56 +/- 0.21 units based on milliliters per millimeter of mercury. It rose significantly to 0.78 +/- 0.28 (P < .0001) with ALF; systemic arterial compliance with OLF was 0.62 +/- 0.19, lower than with ALF (P < .05). Mean arterial pressures and results of oral glucose tolerance tests were similar during ALF, OLF, and second SHF; total cholesterol levels were also not significantly different. However, insulin sensitivity and HDL cholesterol diminished and LDL oxidizability increased with ALF. The marked rise in arterial compliance at least with alpha-linolenic acid reflected rapid functional improvement in the systemic arterial circulation despite a rise in LDL oxidizability. Dietary n-3 fatty acids in flax oil thus confer a novel approach to improving arterial function.

The relevance of the Heart Foundation of Australia's dietary recommendations for adult Australians : a comparison of views of general practitioners, cardiologists and dietitians

PURPOSE: To compare the views of general practitioners, cardiologists and dietitians about the relevance of the Heart Foundation of Australia's dietary recommendations for adult cardiac patients.

BASIC PROCEDURES: Quantitative-cross sectional study. Postal questionnaires were self-completed by 248 Victorian general practitioners (30% response), 189 Australia-wide cardiologists (47% response) and 180 Victorian dietitians (45% response). Responses were represented as percentages and analyses of variance were conducted to explore the impact of the independent variables: age, work status and gender on the dependent variable: dietary recommendation.

MAIN FINDINGS: Approximately half of the recommendations were viewed as strongly important to implement; these related to lean meats, limiting takeaways and cakes/biscuits, and adjusting energy intake. Others of importance were eating fruits, vegetables and fish. However, most of these goals were seen as difficult to achieve. Dietitians appeared to share responses of doctors, except for greater importance of eating fruit and vegetables and a greater difficulty in limiting cakes and biscuits. There was a high level of agreement among the three groups (mean 87%) about patients having difficulty implementing adjusting energy intake.

CONCLUSIONS: There is agreement amongst these professionals that many of the recommendations lack importance, specifically those pertaining to unsaturated oils, low fat dairy products, cholesterol rich foods, intake of legumes and grains and the restriction of salt. This may reflect a need for further nutrition education.

Contribution of Australian cardiologists, general practitioners and dietitians to adult cardiac patients’ dietary behavioural change

Aim:  To investigate the use of behavioural change techniques by cardiologists, general practitioners and dietitians in adult cardiac patients within 12 months of their cardiac event.
Method:  Quantitative cross-sectional surveys. Frequency analyses were conducted on the respondents' answers to questionnaire items. Chi-squared test of independence compared responses of the three professional groups on the questionnaire items. Analyses of variance were conducted to explore the impact of the independent variables: age, sex and time worked on the behavioural change techniques used by the respondents.
Results:  The respondents included 248 general practitioners (30% response), 189 cardiologists (47% response) and 180 dietitians (60% response). General practitioners and cardiologists acted mainly as advocates for dietary change in the dietary management process. Dietitians provided nutrition knowledge and a range of techniques to assist dietary behavioural change. Cardiologists and dietitians shared little nutrition information with general practitioners (cardiologists with general practitioners = 8%, dietitians with general practitioners = 49%).
Conclusion:  The present study shows that cardiac patients may have insufficient access to knowledge of nutrition and techniques to assist them with dietary behavioural change.

Enhancing the dietary management of general practice patients through collaborative care: perspectives of general practitioners and dietitians

Aim:  To describe how general practitioners and dietitians view their role in the dietary management of cardiac patients and to provide insights on how to facilitate collaborative care.
Methods:  Two studies were conducted in Victoria (Australia) 2005–2006. Study One: semi-structured interviews with general practitioners. Study Two: cross-sectional quantitative surveys of general practitioners and dietitians. Study One: texts were analysed using the grounded theory approach. Study Two: frequency analysis was conducted and chi-squared test for independence was used to explore the impact of age, sex and consultation time on the role and reporting scales.
Results:  Study One: Themes arising from the interviews with 30 general practitioners showed their involvement in dietary management fell into three broad roles: ‘Influencing’, ‘Coordinator’ of referrals and dietary ‘Educator’. They described dietetic education as a process that included dietary assessment, education, application of behavioural change techniques and reporting back to general practitioners. Study Two: Respondents were 248 general practitioners (30% response) and 180 dietitians (60% response). General practitioners' counselling consisted mostly of advocating for dietary change, coordinating dietetic referrals and reinforcing dietitians' recommendations. General practitioners considered dietary education as the role of dietitians. Dietitians reported a much broader role in the management of patients with some overlap with general practitioners' roles.
Conclusions:   The findings indicate the need: (i) for more structured reporting to ensure general practitioners receive appropriate information to enable them to reinforce dietetic counselling and recommendations; and (ii) to streamline the communication process in order to expedite dietitians' reports to general practitioners.

Major dietary patterns of young and middle aged women : results from a prospective Australian cohort study

Objective: The aim of this study was to assess the major dietary patterns of two age cohorts of women, to determine to the extent to which the dietary patterns differ between the cohorts and to assess whether they vary according to sociodemographic and behavioural characteristics and patterns of nutrient intake.

Method: Dietary intake was assessed using an 80-item food frequency questionnaire for women aged 50–55 years (n=10 150; ‘middle age’) in 2001 and aged 25–30 years (n=7371; ‘young’) in 2003, from the Australian Longitudinal Study on Women's Health. Factor analysis using principal component extraction was used to identify dietary patterns, and a pattern score was calculated from the consumption of the food items identified with each dietary pattern. Associations between the dietary pattern scores and sociodemographic and behavioural characteristics and nutrient intakes were investigated using regression analysis.

Results: Six dietary patterns were identified and were labelled: cooked vegetables; fruit; Mediterranean-style; processed meat, meat and takeaway; reduced fat dairy; and high-fat and sugar foods. Regression analysis revealed that healthier dietary patterns were significantly associated with other favourable health-related behaviours, higher socioeconomic status and living in urban areas (P-values <0.05).

Conclusions: In spite of differences in the level of consumption of individual food items, the similarity in dietary patterns across two generations of women suggests that policies and interventions to improve diet should focus on social and economic factors and general health-related behaviour rather than different age groups.

Parenting styles, family structure and adolescent dietary behaviour

Objective To examine associations between parenting styles, family structure and aspects of adolescent dietary behaviour.

Design Cross-sectional study.

Setting Secondary schools in the East Midlands, UK.

Subjects Adolescents aged 12–16 years (n 328, 57 % boys) completed an FFQ assessing their consumption of fruit, vegetables, unhealthy snacks and breakfast. Adolescents provided information on parental and sibling status and completed a seventeen-item instrument measuring the general parenting style dimensions of involvement and strictness, from which four styles were derived: indulgent, neglectful, authoritarian, authoritative.

Results After controlling for adolescent gender and age, analysis of covariance revealed no significant interactions between parenting style and family structure variables for any of the dietary behaviours assessed. Significant main effects for family structure were observed only for breakfast consumption, with adolescents from dual-parent families (P < 0·01) and those with no brothers (P < 0·05) eating breakfast on more days per week than those from single-parent families and those with one or more brother, respectively. Significant main effects for parenting style were observed for all dietary behaviours apart from vegetable consumption. Adolescents who described their parents as authoritative ate more fruit per day, fewer unhealthy snacks per day, and ate breakfast on more days per week than those who described their parents as neglectful.

Conclusions The positive associations between authoritative parenting style and adolescent dietary behaviour transcend family structure. Future research should be food-specific and assess the efficacy of strategies promoting the central attributes of an authoritative parenting style on the dietary behaviours of adolescents from a variety of family structures.

Parental correlates of young children's dietary intakes : a review

Evidence suggests that parental modeling, use of feeding strategies, nutrition knowledge, self-efficacy for providing healthy foods and food availability are all likely to be important correlates in determining the dietary habits of young children. This paper reviews the literature regarding parental correlates of the dietary intakes of young children and provides insights regarding areas which may be important in early life but have as yet not been well researched.

Trends in food intake in French children from 1999 to 2007 : results from the INCA (étude Individuelle Nationale des Consommations Alimentaires) dietary surveys

The objectives of the present study were to assess the intake of different food groups in French children aged 3–17 years (n 1455), and to analyse trends since a dietary survey undertaken 8 years ago. Dietary intake was evaluated using data from the 2006–7 cross-sectional INCA2 national dietary survey (étude Individuelle Nationale sur les Consommations Alimentaires), based on a 7 d food record. Dietary intake (percentage of subjects consuming the food group and amount eaten) was assessed for thirty-nine food categories. We observed variations in food consumption by age, sex, North–South regional gradient, seasonal period and educational level of the responding parent. Trends in dietary intake between 1999 and 2007 were determined by comparing the INCA1 (n 1126) and the INCA2 surveys. Both surveys had been carried out using the same methodology. The findings showed a decrease in energy intake in children aged 3–14 years, due to a reduction in the consumption of foods of animal origin and sweetened products. In adolescents aged 15–17 years, energy intake remained rather stable; during this 8-year period, the consumption of meat decreased, whereas the consumption of savoury snacks such as sandwiches and hamburgers significantly increased. These trends occurred during a time of growing concern about overweight and the associated co-morbidities in France. A number of public health measures were implemented over this period to improve dietary habits and physical activity patterns in children and adults. The periodic monitoring of dietary patterns through the INCA surveys is an essential part of the surveillance network in France.

Influence of dietary modifications on the blood pressure response to antihypertensive medication

Identifying dietary modifications that potentiate the blood pressure (BP)-lowering effects of antihypertensive medications and that are practical for free-living people may assist in achieving BP reduction goals. We assessed whether two dietary patterns were effective in lowering BP in persons on antihypertensive therapy and in those not on therapy. Ninety-four participants (38/56 females/males), aged 55.6 (sd 9.9) years, consumed two 4-week dietary regimens in random order (Dietary Approaches to Stop Hypertension (DASH)-type diet and low-Na high-K (LNAHK) diet) with a control diet before each phase. Seated home BP was measured daily for the last 2 weeks in each phase. Participants were grouped based on antihypertensive drug therapy. The LNAHK diet produced a greater fall in systolic BP (SBP) in those on antihypertensive therapy ( - 6.2 (sd 6.0) mmHg) than in those not on antihypertensive therapy ( - 2.8 (sd 4.0) mmHg) (P = 0.036), and this was greatest for those on renin-angiotensin system (RAS) blocker therapy ( - 9.5 (sd 6.4) mmHg) (interaction P = 0.007). The fall in SBP on the DASH-type diet, in those on therapy (overall - 1.1 (sd 6.2) mmHg; renin-angiotensin blocker therapy - 4.2 (sd 4.7) mmHg), was not as marked as that observed on the LNAHK diet. Dietary modifications are an important part of all hypertension management regimens, and a low-Na and high-K diet enhances the BP-lowering effect of antihypertensive medications, particularly those targeting the RAS.