Yvonne Jeanes

Effects of peer influence on dietary intake and physical activity in schoolchildren

OBJECTIVE To investigate the dietary intake and physical activity of boys and girls aged 9-13 years, and the influence of peers on these behaviours. DESIGN Cross-sectional study. SETTING Nine primary and secondary schools in south-west London. SUBJECTS A total of 315 children wore sealed pedometers, provided self-report measures of dietary intake and answered a questionnaire relating to peer influence. Anthropometric measures of height and weight were also obtained. RESULTS Obese children had the lowest reported energy intakes and the lowest step counts per day. Boys took significantly more steps per day than girls, however girls were closer to achieving their recommended cut-offs for physical activity. Girls had lower energy intakes per day and lower BMI Z-scores than boys, however both genders, across all age groups, had higher than recommended intakes of saturated fat. There were significant associations between peer influence and physical activity levels but not between peer influence and dietary intake. CONCLUSIONS Low energy intake and physical activity levels but high saturated fat intakes among boys and girls across all age groups highlight the importance of promoting both physical activity and healthy food choices. The finding that peers have a significant effect on physical activity levels but not on dietary intake offers an important approach for the design of health promotion interventions and obesity prevention programmes. Such designs may be particularly beneficial for obese youth, since the low physical activity levels found could be a major contributing factor to the maintenance of the condition.

An retrospective audit of patients with polycystic ovary syndrome: the effects of a reduced glycaemic load diet

BACKGROUND Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism and chronic anovulation. The aim of this retrospective audit was to determine the patient profile, including anthropometrics, biochemistry and symptoms, and to evaluate the influence of a dietary intervention in women with PCOS. METHODS Data were collected retrospectively from dietetic and medical records from all PCOS patients (n = 88) who attended a dietetic consultation from July 2004 to July 2006. As standard clinic practice, a reduced glycaemic load diet had been prescribed, with energy reduction in overweight patients. Follow-up data were available for 59 patients. RESULTS Fifty-eight patients had a body mass index (BMI) <or= 24.9 kg m(-2) and 30 had a BMI >or= 25 kg m(-2). Thirty-six patients, with a BMI <or= 24.9 kg m(-2), self-reported central weight gain at their initial appointment. Over two-thirds of patients self-reported one or more of the following symptoms: carbohydrate cravings, hypoglycaemia, tiredness and hunger. At the follow-up appointment, BMI and waist circumference significantly decreased in overweight patients (P < 0.05). Seventy-one percent of women self-reported hypoglycaemia initially; this was reduced to 13% at follow-up (P < 0.01). CONCLUSIONS The audit indicated a low glycaemic load diet in combination with medication may contribute to an improvement in symptom relief in patients with PCOS.

Physical activity and dietary intake of children aged 9-11 years and the influence of peers on these behaviours: a 1-year follow-up.

Background:This study investigated physical activity and dietary intake of children aged 9–11 years, and the influence of peers on these behaviours over a 2-year period.Methods:A total of 106 (64 girls; 42 boys) children were investigated annually, over 2 years. Measures included physical activity (sealed pedometer), self-report measures of dietary intake and physical activity, and a peer influence questionnaire. Anthropometric measures of height and weight were also obtained.Results:The findings reveal insufficient energy intakes, physical activity levels and fruit and vegetable consumption but high intakes of saturated fat and sodium, over time, in both boys and girls. Both male calcium and female iron intakes were also of concern. Throughout the survey, peers were found to influence physical activity behaviour but not dietary intake.Conclusions:The fact that youth consistently failed to meet established nutrition and physical activity recommendations highlights the importance of promoting physical activity and healthy eating to children younger than 9 years of age. The finding that peers significantly influence physical activity behaviour over time should be considered when designing new physical activity interventions aimed at young people.

Habitual dietary intake, eating pattern and physical activity of women with polycystic ovary syndrome

Background/Objective:Diet and lifestyle modifications may be of benefit in the management of polycystic ovary syndrome (PCOS), but there is a paucity of data on these behaviours in women with PCOS. This study aims to address this through a comprehensive investigation of the habitual diet and activity patterns of UK women with PCOS and their alignment with dietary recommendations for health.Subjects/Methods:A 7-day-estimated food and activity diary and questionnaire was completed by 210 women with PCOS for calculation of activity levels, energy and nutrient intakes and dietary glycaemic index (GI).Results:Mean (s.d.) body mass index (BMI) was 27.4 (7.3) kg/m2 (n=183), with 53% of women with PCOS having a BMI>25 kg/m2. Of the overweight women, approximately half were not achieving sufficient physical activity to promote weight loss. More frequent eating episodes and a lower BMI were weakly associated (r=−0.158, P=0.034). Mean percentage energy from fat was 38 (7)% (12% energy from saturated fat), with 68% of women with PCOS consuming > 35% energy from fat. Mean dietary GI was higher in obese women with PCOS, compared with healthy weight women with PCOS (55.7 (3.4) and 53.8 (4.0), respectively; P=0.043).Conclusion:Many women with PCOS are not achieving dietary intakes and levels of physical activity that optimise symptom management and disease prevention. Advice should focus on fat quality and quantity and carbohydrate modification. There is a need for further robust research into the role of dietary GI in the PCOS population.

An Isocaloric Low Glycemic Index Diet Improves Insulin Sensitivity in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting 5% to 10% of women worldwide. Approximately half of women with PCOS are lean, yet may still present with central obesity and metabolic disturbances. Low-glycemic index (GI) dietary intervention studies have demonstrated improvements in insulin sensitivity in insulin-resistant populations; however, there is little evidence of this effect in women with PCOS. This research aimed to determine the efficacy of an isocaloric low-GI dietary intervention on insulin sensitivity, independent of weight change, in women with PCOS. A nonrandomized 12-week low-GI dietary intervention, preceded by a 12-week habitual diet control phase and proceeded by a 12-week follow-up phase was conducted. Dietary intake, body composition, and metabolic risk markers were determined at baseline, after completion of the habitual diet control phase, and after the low-GI dietary intervention. Twenty-six participants were recruited at baseline, 22 commenced and 21 participants completed the low-GI dietary intervention phase. The primary outcome was change in insulin sensitivity. Secondary outcomes included assessment of changes to lipids, body composition, and estimated macronutrient intake. Repeated measures analysis of variance with Bonferroni correction were used to detect changes to outcomes across study timepoints. Twenty-one women with PCOS with mean (± standard deviation) age of 32.1±6.7 years completed the 12-week low-GI dietary intervention. As expected, no significant changes occurred during the 12-week habitual diet control phase. However, during the dietary intervention phase, dietary GI decreased from 54.5±3.5 to 48.6±5.1 (P<0.001) with a concurrent small reduction in saturated fat intake (12.4%±3% to 11.7%±3% contribution from energy, P=0.03), despite no specific recommendations to modify fat intake. Measures of insulin sensitivity and nonesterified fatty acid improved after intervention (P=0.03 and P=0.01, respectively). This is the first study to implement an isocaloric low-GI diet in women with PCOS and findings may contribute to the limited research in this area.

Dietary management of women with polycystic ovary syndrome in the United Kingdom: the role of dietitians

BACKGROUND Polycystic ovary syndrome (PCOS) is a common endocrine condition associated with hyperandrogenism, infertility and metabolic dysfunction. Weight management through diet and lifestyle modifications are fundamental to its management; however, presently, there are no official dietary guidelines. The present study aimed to explore the dietary and lifestyle strategies followed by women with PCOS and the contribution of dietitians to its management. METHODS A questionnaire was completed by 105 UK dietitians focused on the service provided and a patient questionnaire and 7-day food diary were completed by women with PCOS (n = 206 and n = 196, respectively). Food diaries were analysed for energy and macronutrient intake and the questionnaire focused on the dietary advice received. RESULTS Advice provided by dietitians focused on a reduction in energy intake (78%) and dietary glycaemic index (77%), often in combination. Of the women with PCOS who were following a diet specifically for their PCOS (57%), regimes included a low glycaemic index (34%), weight loss diets (16%) or a combination (26%). Of interest, 73% of overweight women were not following a diet to promote weight loss. Nutritional information predominately came from books, with only 15% of women having seen a dietitian. Eighty-four percent of women with PCOS who had increased physical activity (48%) self-reported an improvement in their symptoms. CONCLUSIONS Women with PCOS recognise the importance of diet, but few received dietary advice from a registered dietitian. The dietary information women with PCOS received was often from an unregulated source. A consensus statement of evidence-based dietary advice for women with PCOS is needed and would be a useful resource for dietitians.

The effect of the classical and medium chain triglyceride ketogenic diet on vitamin and mineral levels

BACKGROUND The risk of nutritional deficiency in children on restrictive dietary treatments and a lack of ketogenic diet (KD)-specific UK supplements raises concerns about micronutrient status. Vitamin A, E, zinc, selenium and magnesium levels were therefore examined in children with intractable epilepsy treated with the KD. METHODS Plasma vitamins A and E, zinc, selenium and magnesium levels were measured at baseline and after 3, 6 and 12months on the classical (n=46) or medium chain triglyceride (MCT) (n=45) KD in children aged 2-16years, as part of a randomised trial, and pairwise comparisons with baseline were performed. RESULTS Data were available from 91 children. From baseline to 12months, mean plasma vitamin A decreased from 1.41μmol L(-1) to 1.13μmol L(-1) in the classical group (P<0.001) but increased from 1.52μmol L(-1) to 1.81μmol L(-1) in the MCT group (P<0.001). Mean plasma vitamin E increased from 22.7μmol L(-1) to 33.2μmol L(-1) in the classical group (P<0.001) and from 22.3 μmol L(-1) to 23.3μmol L(-1) in the MCT group (P<0.05). No significant change in plasma zinc was seen at 12months, although mean plasma selenium decreased from 0.95μmol L(-1) to 0.88μmol L(-1) in the group as a whole (P<0.05). Mean plasma magnesium decreased from 0.87mmol L(-1) to 0.83mmol L(-1) in the group as a whole (P<0.001); when subdivided by KD type, this was limited to the classical group. CONCLUSIONS Changes in plasma vitamins A and E and the decline in magnesium status after 12months of KD treatment suggest that micronutrient status may be suboptimal in this group and that available formulations for KD supplementation may need reviewing.

Beverage consumption and BMI of British schoolchildren aged 9–13 years

OBJECTIVE Adequate fluid intake has been well documented as important for health but whether it has adverse effects on overall energy and sugar intakes remains under debate. Many dietary studies continue to refrain from reporting on beverage consumption, which the present study aimed to address. DESIGN A cross-sectional survey investigated self-reported measures of dietary intake and anthropometric measurements. SETTING Primary and secondary schools in south-west London, UK. SUBJECTS Boys and girls (n 248) aged 9–13 years. RESULTS Boys consumed 10 % and girls consumed 9 % of their daily energy intake from beverages and most children had total sugar intakes greater than recommended. Beverages contributed between a quarter and a third of all sugars consumed, with boys aged 11–13 years consuming 32 % of their total sugar from beverages. There was a strong relationship between consumption of beverages and energy intake; however, there was no relationship between beverage type and either BMI or BMI Z-score. Fruit juices and smoothies were consumed most frequently by all girls and 9–10-year-old boys; boys aged 11–13 years preferred soft drinks and consumed more of their daily energy from soft drinks. Milk and plain water as beverages were less popular. CONCLUSIONS Although current health promotion campaigns in schools merit the attention being given to improving hydration and reducing soft drinks consumption, it may be also important to educate children on the energy and sugar contents of all beverages. These include soft drinks, as well as fruit juices and smoothies, which are both popular and consumed regularly.

Body mass, frequency of eating and breakfast consumption in 9–13-year-olds

BACKGROUND Unhealthy eating patterns in childhood can lead to adverse health conditions, particularly obesity. However, debate remains around the precise eating behaviours that lead to these conditions. The present study aimed to address this lack of evidence by reporting on the eating frequency, breakfast consumption and body mass index (BMI, kg m(-2) ) of youth in the UK. METHODS A total of 264 (133 boys and 131 girls) participants, aged 10-13years, completed self-report measures of dietary intake via 3-day food/drink diaries (Friday to Sunday). Trained researchers recorded height and weight to calculate the BMI. Diaries were analysed using dietplan 6 nutritional analysis software (Forestfield Software, Horsham, UK) and multivariate linear regression was used to examine any association between breakfast consumption, frequency of eating and BMI. RESULTS No relationship existed between BMI Z-score, eating frequency and breakfast consumption. However, frequent breakfast consumers had significantly lower mean (SD) BMI Z-scores [0.18(1.06) versus 0.57(1.23)] and higher intakes of iron, calcium and vitamin E than those who did not eat breakfast regularly. Those aged ≥11years consumed breakfast less frequently [0.92(0.20)] and were less likely to eat regularly [4.6(1.4)] than those aged ≤10years. CONCLUSIONS Older boys were the least likely to eat regularly and the least likely to consume breakfast. Promoting the importance of regular eating, particularly breakfast consumption to these boys, may be essential to ensure healthier, long-term eating patterns. Furthermore, the lower breakfast intakes in 11-13-year-olds and higher BMI Z-scores of those who did not eat breakfast regularly should be monitored.

Habitual fat intake predicts memory function in younger women.

High intakes of fat have been linked to greater cognitive decline in old age, but such associations may already occur in younger adults. We tested memory and learning in 38 women (25 to 45 years old), recruited for a larger observational study in women with polycystic ovary syndrome. These women varied in health status, though not significantly between cases (n = 23) and controls (n = 15). Performance on tests sensitive to medial temporal lobe function (CANTABeclipse, Cambridge Cognition Ltd, Cambridge, UK), i.e., verbal memory, visuo-spatial learning, and delayed pattern matching (DMS), were compared with intakes of macronutrients from 7-day diet diaries and physiological indices of metabolic syndrome. Partial correlations were adjusted for age, activity, and verbal IQ (National Adult Reading Test). Greater intakes of saturated and trans fats, and higher saturated to unsaturated fat ratio (Sat:UFA), were associated with more errors on the visuo-spatial task and with poorer word recall and recognition. Unexpectedly, higher UFA intake predicted poorer performance on the word recall and recognition measures. Fasting insulin was positively correlated with poorer word recognition only, whereas higher blood total cholesterol was associated only with visuo-spatial learning errors. None of these variables predicted performance on a DMS test. The significant nutrient–cognition relationships were tested for mediation by total energy intake: saturated and trans fat intakes, and Sat:UFA, remained significant predictors specifically of visuo-spatial learning errors, whereas total fat and UFA intakes now predicted only poorer word recall. Examination of associations separately for monounsaturated (MUFA) and polyunsaturated fats suggested that only MUFA intake was predictive of poorer word recall. Saturated and trans fats, and fasting insulin, may already be associated with cognitive deficits in younger women. The findings need extending but may have important implications for public health.