Effect of carbohydrate-protein supplementation on endurance training adaptations.

PURPOSE: To examine the influence of post-exercise protein feeding upon the adaptive response to endurance exercise training. METHODS: In a randomised parallel group design, 25 healthy men and women completed 6 weeks of endurance exercise training by running on a treadmill for 30-60 min at 70-75% maximal oxygen uptake (VO2max) 4 times/week. Participants ingested 1.6 g per kilogram of body mass (g kg BM-1) of carbohydrate (CHO) or an isocaloric carbohydrate-protein solution (CHO-P; 0.8 g carbohydrate kg BM-1 + 0.8 g protein kg BM-1) immediately and 1 h post-exercise. Expired gas, blood and muscle biopsy samples were taken at baseline and follow-up. RESULTS: Exercise training improved VO2max in both groups (p ≤ 0.001), but this increment was not different between groups either in absolute terms or relative to body mass (0.2 ± 0.2 L min-1 and 3.0 ± 2 mL kg-1 min-1, respectively). No change occurred in plasma albumin concentration from baseline to follow-up with CHO-P (4.18 ± 0.18 to 4.23 ± 0.17 g dL-1) or CHO (4.17 ± 0.17 to 4.12 ± 0.22 g dL-1; interaction: p > 0.05). Mechanistic target of rapamycin (mTOR) gene expression was up-regulated in CHO-P (+ 46%; p = 0.025) relative to CHO (+ 4%) following exercise training. CONCLUSION: Post-exercise protein supplementation up-regulated the expression of mTOR in skeletal muscle over 6 weeks of endurance exercise training. However, the magnitude of improvement in VO2max was similar between groups.

Adherence to a Gluten Free Diet Is Associated with Receiving Gluten Free Foods on Prescription and Understanding Food Labelling.

Treatment of coeliac disease requires a strict gluten-free (GF) diet, however, a high proportion of patients do not adhere to a GF diet. The study explores the practical challenges of a GF diet and dietary adherence in Caucasian and South Asian adults with coeliac disease. Patients with biopsy- and serology-proven coeliac disease were recruited from a hospital database. Participants completed a postal survey (n = 375), including a validated questionnaire designed to measure GF dietary adherence. Half of Caucasians (53%) and South Asians (53%) were adhering to a GF diet. The quarter of patients (n = 97) not receiving GF foods on prescription had a lower GF dietary adherence score compared with those receiving GF foods on prescription (12.5 versus 16.0; p < 0.001). Not understanding food labelling and non-membership of Coeliac UK were also associated with lower GF dietary adherence scores. A higher proportion of South Asian patients, compared with Caucasians, reported difficulties understanding what they can eat (76% versus 5%; p < 0.001) and understanding of food labels (53% versus 4%; p < 0.001). We recommend retaining GF foods on prescription, membership of a coeliac society, and regular consultations with a dietitian to enable better understanding of food labels. Robust studies are urgently needed to evaluate the impact of reducing the amount of GF foods prescribed on adherence to a GF diet in all population groups.

Metabolic consequences of obesity and insulin resistance in polycystic ovary syndrome: diagnostic and methodological challenges.

Women with polycystic ovary syndrome (PCOS) have a considerable risk of metabolic dysfunction. This review aims to present contemporary knowledge on obesity, insulin resistance and PCOS with emphasis on the diagnostic and methodological challenges encountered in research and clinical practice. Variable diagnostic criteria for PCOS and associated phenotypes are frequently published. Targeted searches were conducted to identify all available data concerning the association of obesity and insulin resistance with PCOS up to September 2016. Articles were considered if they were peer reviewed, in English and included women with PCOS. Obesity is more prevalent in women with PCOS, but studies rarely reported accurate assessments of adiposity, nor split the study population by PCOS phenotypes. Many women with PCOS have insulin resistance, though there is considerable variation reported in part due to not distinguishing subgroups known to have an impact on insulin resistance as well as limited methodology to measure insulin resistance. Inflammatory markers are positively correlated with androgen levels, but detailed interactions need to be identified. Weight management is the primary therapy; specific advice to reduce the glycaemic load of the diet and reduce the intake of pro-inflammatory SFA and advanced glycation endproducts have provided promising results. It is important that women with PCOS are educated about their increased risk of metabolic complications in order to make timely and appropriate lifestyle modifications. Furthermore, well-designed robust studies are needed to evaluate the mechanisms behind the improvements observed with dietary interventions.

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.

Breakfast habits, beliefs and measures of health and wellbeing in a nationally representative UK sample.

The aim of this study was to report UK adult breakfasting habits, beliefs and the relationship of both with measures of personality, health and wellbeing including physical activity and body mass index (BMI). A nationally representative sample of 1068 adults completed a web-based survey, combining standardised scales and self-designed questionnaire statements. Sixty-four percent of respondents consumed breakfast daily whilst 6% never ate breakfast. Breakfasting frequency was found to correlate with conscientiousness, wellbeing and age and general health. The survey found that breakfast eaters strongly believe that breakfast helps weight control and weight loss. Breakfast eaters were more likely to partake in vigorous exercise, although there was no significant difference in BMI. Multi-variate analysis identified conscientiousness, cognitive restraint and age as making unique contributions to predicting breakfast frequency. This study provides further support for the view that breakfast eating is likely to be a proxy-variable for a healthy lifestyle. The role of breakfast and related beliefs should be taken into consideration in breakfast behaviour research, interventions and health and wellbeing campaigns.

Ethnic dress, vitamin D intake, and calcaneal bone health in young women in the United Kingdom.

Clothing styles that conceal skin from ultraviolet sun radiation contribute to vitamin D deficiency, especially in veiled female minorities in high latitudes. This is the first research into possible effects of ethnic dress on the os calcis and the first study outside North Africa and the Middle East to investigate whether discernible differences in bone quality exist between veiled and unveiled women. The limited previous research into clothing habits and bone health has been inconclusive. One hundred eight women aged 18--45yr living in the United Kingdom (around 51° north) were analyzed. Forty-three consistently covered arms, hair, and neck when outdoors, whereas 65 consistently had arms, hair, neck, and possibly legs exposed. The quantitative ultrasound scanning (QUS) measurements at the calcaneus were speed of sound (SOS) and broadband ultrasound attenuation (BUA), which were translated into a single clinical value, stiffness index (SI). Dietary intake of vitamin D and calcium was estimated using a validated food frequency questionnaire, and several other risk factors were assessed. There was no significant difference in SI between veiled and unveiled participants (101.30±1.71 vs 99.98±1.86; p=0.721); SOS and BUA were also not significantly different. However, smoking and long-term use of steroid medication were significant predictors of calcaneal bone quality, confirming existing research. Our analysis suggests that clothing style alone does not lead to appreciable differences in the quality of the os calcis in young women in the United Kingdom as assessed by QUS.

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.