Diet, lifestyle and the risk of Type 2 Diabetes Mellitus in women

Background Previous studies have examined individual dietary and lifestyle factors in relation to type 2 diabetes, but the combined effects of these factors are largely unknown. Methods We followed 84,941 female nurses from 1980 to 1996; these women were free of diagnosed cardiovascular disease, diabetes, and cancer at base line. Information about their diet and lifestyle was updated periodically. A low-risk group was defined according to a combination of five variables: a body-mass index (the weight in kilograms divided by the square of the height in meters) of less than 25; a diet high in cereal fiber and polyunsaturated fat and low in trans fat and glycemic load (which reflects the effect of diet on the blood glucose level); engagement in moderate-to-vigorous physical activity for at least half an hour per day; no current smoking; and the consumption of an average of at least half a drink of an alcoholic beverage per day. Results During 16 years of follow-up, we documented 3300 new cases of type 2 diabetes. Overweight or obesity was the single most important predictor of diabetes. Lack of exercise, a poor diet, current smoking, and abstinence from alcohol use were all associated with a significantly increased risk of diabetes, even after adjustment for the body-mass index. As compared with the rest of the cohort, women in the low-risk group (3.4 percent of the women) had a relative risk of diabetes of 0.09 (95 percent confidence interval, 0.05 to 0.17). A total of 91 percent of the cases of diabetes in this cohort (95 percent confidence interval, 83 to 95 percent) could be attributed to habits and forms of behavior that did not conform to the low-risk pattern. Conclusions Our findings support the hypothesis that the majority of cases of type 2 diabetes could be prevented by the adoption of a healthier lifestyle.

Relationship of high energy expenditure and variation in dietary intake with reporting accuracy on 7 day food records and diet histories in a group of healthy adult volunteers

Objectives: To assess the accuracy of reporting from both a diet history and food record and identify some of the characteristics of more accurate reporters in a group of healthy adult volunteers for an energy balance study. Design: Prospective measurements in free-living people. Setting: Wollongong, Australia. Subjects: Fifteen healthy volunteers (seven male, eight female; aged 22 -59 y; body mass index (BMI) 19 - 33 kg/m(2)) from the local community in the city of Wollongong, Australia. Interventions: Measurement of energy intake via diet history interview and 7 day food records, total energy expenditure by the doubly labelled water technique over 14 days, physical activity by questionnaire, and body fat by dual-energy X-ray absorptiometry. Results: Increased misreporting of energy intake was associated with increased energy expenditure (r = 0.90, P < 0.0001, diet history; r(s)=0.79, P=0.0005, food records) but was not associated with age, sex, BMI or body fat. Range in number of recorded dinner foods correlated positively with energy expenditure (r(s)=0.63, P=0.01) and degree of misreporting (r(s)=0.71, P=0.003, diet history; r(s)=0.63, P=0.01, food records). Variation in energy intake at dinner and over the whole day identified by the food records correlated positively with energy expenditure (r=0.58, P = 0.02) and misreporting on the diet history (r=0.62, P=0.01). Conclusions: Subjects who are highly active or who have variable dietary and exercise behaviour may be less accurate in reporting dietary intake. Our findings indicate that it may be necessary to screen for these characteristics in studies where accuracy of reporting at an individual level is critical. Sponsorship: The study was supported in part by Australian Research Council funds made available through the University of Wollongong.

Magnesium, insulin resistance and body composition in healthy postmenopausal women

Objective: This study was conducted to determine the association between magnesium (Mg), body composition and insulin resistance in 136 sedentary postmenopausal women, 50 to 77 years of age. Methods: Diabetics, hypertensives and women on hormonal replacement therapy were excluded and the remaining 74 were divided according to BMI≥25 (obese: OG) and BMI<25 kg/m2 (non-obese: NOG). Nutritional data disclosed that intakes were high for protein and saturated fat, low for carbohydrates, polyunsaturated fat and Mg and normal for the other nutrients, according to recommended dietary allowances (RDA). Mg values in red blood cells (RBC-Mg) and plasma (P-Mg), were determined, as were fasting glucose, and insulin levels, Homeostasis Model Assessment (HOMA), body mass index (BMI), body fat percent (BF %), abdominal fat (AF) and free fat mass (FFM). Results: RBC-Mg values were low in both groups when compared with normal values. There were significant differences in body composition parameters, HOMA and insulin levels, with higher basal insulin levels in OG. RBC-Mg was directly correlated with insulin, HOMA and FFM in both groups, according to Pearson correlations. HOMA in OG was also directly correlated with BMI, FFM and AF. In NOG, HOMA was only correlated with FFM. The low RBC-Mg levels observed were probably due to low Mg intake and to deregulation of factors that control Mg homeostasis during menopause. Conclusions: Both Mg deficit and obesity may independently lead to a higher risk for insulin resistance and cardiovascular disease.

Effects of a home-based exercise program in body composition, abdominal fat and lipid profile in patients with coronary artery disease

Introduction: Coronary artery disease and aging seems to be associated with a sedentary lifestyle, contributing to increased abdominal fat and consequently metabolic complications. The exercise can break this cycle by stimulating lipolysis and the use of fatty acids. In Europe there is still a lack of cardiac rehabilitation programmes in hospitals, therefore, this study aims to demonstrate the advantages of implementing home-based exercise programmes, as well as, their effects on cardiovascular prevention. This study analyzed the effects of a home-based exercise programme, in patients with coronary artery disease (myocardial infarction for 1 year), in body composition, abdominal fat, lipid profile. Methods: An ongoing randomized controlled trial with a sample of 20 participants were randomly allocated to intervention (n = 10) and control groups (n = 10). Intervention group performed a specific exercise programme during 8 weeks, consisting of ten home based exercises taking into account flexibility, muscle endurance and strength as well as cardiovascular endurance. Skinfolds thickness were measure to calculate the percentage of total fat: Skinfolds used were suprailiac, abdominal horizontal and vertical. Body mass index calculation and blood tests for lipidic profile were performed. Results: After eight weeks the intervention group decreased significantly the percentage of total fat (p < 0.05), the suprailiac skinfold (p < 0.05), the abdominal horizontal and vertical skinfold (p < 0.05) when compared with control group. In the intervention group it was observed after 8 weeks a significant decrease in body mass index, LDL-cholesterol and triglycerides. Conclusions: Home-based exercise programme influenced body composition, abdominal fat and lipid profile. These results highlight the importance of implementing home based exercises that are easy and cheap to implement in cardiac patients, in order to promote health and reduce cardiovascular risk factors.

Autonomia funcional em idosos : caracterização multidimensional em idosos utentes de um centro de saúde urbano

RESUMO: Tivemos como objectivo do presente trabalho avaliar a capacidade funcional, e factores eventualmente a ela associados, numa amostra de 152 idosos ambulatórios, sem doenças agudas ou graves, utentes de um centro de saúde urbano. Cada avaliação consistiu numa entrevista, mediante um inquérito sobre capacidade funcional, morbilidade, estado mental e aspectos sociais, e no estudo da composição corporal. As perguntas referentes às variáveis estudadas foram por nós desenvolvidas e estruturadas com base em escalas internacionais validadas e de utilização comum na avaliação de idosos, excepto para as variáveis em que não encontrámos escalas com essas características. Os seus quesitos foram incluídos como perguntas e respostas estruturadas e pré-codificadas, permitindo a atribuição de uma pontuação a cada variável e a sua posterior divisão dicotómica. Aplicámos as escalas de Katz e de Lawton para a avaliação das actividades de autonomia física e instrumental da vida diária, a escala de Grimby para a avaliação da actividade física, a escala de Hamilton e o teste de Folstein para a avaliação do estado mental nas vertentes afectiva e cognitiva e a escala de Graffar para caracterizar a classe social, e perguntas sobre locomoção, autoavaliação da saúde, queixas de saúde presentes e rede social. Fizemos o registo da morbilidade segundo a International Classification of Primary Care - ICPC. A avaliação antropométrica constou da medição do peso, da altura, dos perímetros do braço, da cintura, da anca e proximal da coxa, e das pregas bicipital, tricipital, sub-escapular e supra-ilíaca. Foi também feita a estimativa da composição corporal por cálculos derivados de índices antropométricos e de bioimpedância eléctrica corporal total, o doseamento de algumas proteínas plasmáticas e a quantificação da força de preensão. Analisámos os resultados obtidos por grupos quanto ao sexo e à idade, dividida nos escalões etários 65 a 74 anos e mais do que 74 anos. Por regressão linear múltipla, foi testado o efeito do sexo e da idade sobre os valores medidos, para cada uma das variáveis e cada uma das suas pontuações parciais, sendo considerado como evidência de um efeito estaticamente significativo um valor “p” inferior a 0,05.Resumimos do seguinte modo os dados obtidos e a sua comparação com os dos estudos que seleccionámos como referência: A média de idades da amostra foi de 74 anos, sendo um terço destes do sexo masculino. Na sua maioria eram independentes em locomoção e funcionalidade, praticavam alguma actividade física, classificavam a sua saúde como razoável ou boa, apresentavam sintomatologia activa, não tinham depressão ou demência, tinham quem os acompanhasse embora cerca de metade apresentasse algum grau de isolamento, eram de baixa classe social, tinham excesso de peso, valores elevados de massa gorda, parâmetros plasmáticos proteicos compatíveis com ausência de doenças agudas ou graves e considerável força muscular de preensão. Na análise descritiva por grupos quanto ao sexo e/ou à idade, verificou-se que as mulheres e os mais idosos apresentavam maior isolamento social e os valores mais baixos de massa magra, hemoglobina e força de preensão. As mulheres tinham maior prevalência de dependência em autonomia física, depressão e valores mais baixos de transferrina. Os mais idosos apresentavam maior dependência em funcionalidade, menor actividade física, maior prevalência de demência, índice de massa corporal menos elevado, e valores mais baixos de albumina. Não se verificou prevalência de piores resultados dicotómicos nos homens nem no escalão etário menos idoso. Não teve relação com o sexo ou a idade o compromisso em autonomia instrumental, a presença de morbilidade ou a baixa classe social, assim como a não perturbação da locomoção e dos níveis de somatomedina-C. A análise comparativa com estudos multidimensionais em idosos portugueses e europeus ambulatórios revelou que a nossa amostra apresentava muitas características semelhantes às desses idosos. Assim, tinham elevada independência em locomoção, considerável independência em autonomia física e menor independência em autonomia instrumental; prática de actividade física ligeira, as mulheres dentro e os homens fora de casa; maior prevalência de morbilidade a nível dos aparelhos locomotor e cardiocirculatório, nos nossos idosos com pouca flutuação na autoavaliação de saúde; pequena prevalência de depressão e de demência; maior isolamento social nas mulheres e nas mais idosas; factores de classe social de baixo nível, diferindo apenas em relação aos idosos do norte da Europa que apresentavam elevada escolaridade e profissões mais diferenciadas; características biométricas sobreponíveis às dos idosos portugueses e às dos do sul da Europa, com tendência para o excesso de peso e proporção elevada de massa gorda; e doseamentos plasmáticos proteicos e força muscular de preensão compatíveis com ausência de doenças agudas ou crónicas graves. A comparação com os referidos estudos em relação ao risco de dependência, revelou semelhanças na associação entre dependência funcional e idade avançada, morbilidade, alteração do estado mental e isolamento social. Na amostra que estudámos não obtivemos associação entre dependência e o sexo feminino, facto que se verificou no estudo nacional de Almeida et al. e nos estudos multicêntricos europeus, ou o grau de escolaridade, como no estudo francês. Podemos concluir que, com o instrumento de avaliação que utilizámos, foi possível detectar e caracterizar perturbações numa amostra de idosos ambulatórios, a maioria funcionalmente independentes, sem alterações do estado mental, mas apresentando morbilidade activa, tendência para a obesidade, e actividade física ligeira. Nos que apresentaram alterações, estas foram mais frequentes no sexo feminino e nos indivíduos com mais de 74 anos. A escala de funcionalidade desenvolvida foi sensível aos efeitos da idade e permitiu o cálculo do risco de dependência em relação às outras variáveis estudadas, sendo mais marcante a associação com baixa actividade física, presença de queixas de saúde, demência e índice de massa corporal elevado. Consideramos que a metodologia que empregámos poderá contribuir para a avaliação de capacidades, cujo conhecimento sistemático nos idosos se impõe. ------------- ABSTRACT: The main objective of the present work was to evaluate functional capacity and related factors, in a sample of 152 ambulatory elderly, free from acute or serious disease, attending an urban health centre. Each evaluation included an interview, with a questionnaire about functional capacity, morbidity, mental health and social aspects, and the study of body composition. The questions were developed and structured in accordance with international validated scales usually applied in the evaluation of the elderly, whenever there were scales for that purpose. Their items were included as structured pre-coded questions and answers, so that each variable could have its own quotation and be dichotomised. We employed Katz and Lawton scales for basic and instrumental activities of daily living, Grimby scale for physical activity, Hamilton scale for depression, Folstein’s Mini Mental State Examination for cognitive ability and Graffar scale for social class, and questions about walking, health perception, active complaints and social network. The symptoms register was done according to the International Classification of Primary Care - ICPC. The anthropometric exam involved the determination of height and weight, arm, waist, hip and proximal thigh circumferences, and biceps, triceps, subscapular and suprailiac skinfolds. For the body composition calculation we employed equations derived from anthropometric indices, and from measurement of total body bioelectric impedance. We also measured some plasma proteins and handgrip strength. The analysis of results was done by sex and age groups, separating those with 65 to 74 years from those older than 74 years. The effects of sex and age were tested by linear multiple regression, for each variable and its components. Presented "p" values being considered statistically significative if less than 0,05. The results we obtained and their comparison with the studies we choose as reference can be summarised as follows: Mean age of the sample was 74 years and about one third were men. Most of them were independent in gait and functionality, practised some physical activity, rate their health as fair or good, had physical complaints, had not depression or dementia, had some companionship although almost half of them with stigmas of isolation, belonged to low social class, were in the range of overweight, had raised values of fat mass, plasma proteins in accordance with no acute or serious disease, and considerable handgrip strength. The analysis of groups by sex and age revealed that women and the eldest had the greater social isolation and the lowest values of free fat mass, haemoglobin and handgrip strength. Women had the higher dependence in basic activities of daily living, more depression and lower levels of transferrin. The eldest were more dependent in functionality, had greater prevalence of dementia, less physical activity, less raised body mass index and lower levels of albumin. Men alone and the age range of 65 to 74 did not show any prevalence of the worse dichotomised results. There was no relationship between sex or age and instrumental activities of daily living, morbidity or low social class, and unaffected gait or somatomedin-C levels. The comparison of results with multidimensional studies in portuguese and european ambulatory elderly showed that our sample had many similarities with theirs. They were independent in gait and activities of daily living; practiced light physical activity, women indoors and men outdoors; had greater morbidity at locomotor and cardiovascular systems, with small latitude in health evaluation; low prevalence of depression and dementia; social isolation predominantly in older women; and low social class factors, witch is only different from those of north Europe who had higher education levels and professional carriers; biometric characteristics similar to other portuguese and south Europe elders, with tendency for overweight and high proportion of fat mass; and plasma protein levels and handgrip strength in accordance with no acute or chronic serious disease. The comparison to the referred studies in relation to dependency risk, showed similarities in the association of dependency and age, morbidity,altered mental state and social isolation. We did not find association between dependency and sex, as it was found in the portuguese study of Almeida et al. and the european multicentric studies, or the education level, as in the french study. We conclude that, with the evaluation battery we employed, it was possible to detect and characterise alterations in a sample of ambulatory elderly, most of whom were functionally independent and had no alterations in mental state, but had active morbidity, tendency to obesity, and only light physical activity. Those that had some alteration, were more frequently women and the eldest. The functionality scale we developed showed to be sensitive to age effects and suitable for the calculation of risk of dependency, being more important the association with low physical activity, active complaints, dementia and high body mass index. We consider that the methodology we applied can contribute to the evaluation of capabilities that should be systematically sought for in the elderly.

Meta-analysis identifies 13 new loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution.

Waist-hip ratio (WHR) is a measure of body fat distribution and a predictor of metabolic consequences independent of overall adiposity. WHR is heritable, but few genetic variants influencing this trait have been identified. We conducted a meta-analysis of 32 genome-wide association studies for WHR adjusted for body mass index (comprising up to 77,167 participants), following up 16 loci in an additional 29 studies (comprising up to 113,636 subjects). We identified 13 new loci in or near RSPO3, VEGFA, TBX15-WARS2, NFE2L3, GRB14, DNM3-PIGC, ITPR2-SSPN, LY86, HOXC13, ADAMTS9, ZNRF3-KREMEN1, NISCH-STAB1 and CPEB4 (P = 1.9 × 10⁻⁹ to P = 1.8 × 10⁻⁴⁰) and the known signal at LYPLAL1. Seven of these loci exhibited marked sexual dimorphism, all with a stronger effect on WHR in women than men (P for sex difference = 1.9 × 10⁻³ to P = 1.2 × 10⁻&supl;³). These findings provide evidence for multiple loci that modulate body fat distribution independent of overall adiposity and reveal strong gene-by-sex interactions.

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms.

Dose-dependent positive association between cigarette smoking, abdominal obesity and body fat: cross-sectional data from a population-based survey.

ABSTRACT: BACKGROUND: Although smokers tend to have a lower body-mass index than non-smokers, smoking may favour abdominal body fat accumulation. To our knowledge, no population-based studies have assessed the relationship between smoking and body fat composition. We assessed the association between cigarette smoking and waist circumference, body fat, and body-mass index. METHODS: Height, weight, and waist circumference were measured among 6,123 Caucasians (ages 35-75) from a cross-sectional population-based study in Switzerland. Abdominal obesity was defined as waist circumference>=102 cm for men and >=88 cm for women. Body fat (percent total body weight) was measured by electrical bioimpedance. Age- and sex-specific body fat cut-offs were used to define excess body fat. Cigarettes smoked per day were assessed by self-administered questionnaire. Age-adjusted means and odds ratios were calculated using linear and logistic regression. RESULTS: Current smokers (29% of men and 24% of women) had lower mean waist circumference, body fat percentage, and body-mass index compared with non-smokers. Age-adjusted mean waist circumference and body fat increased with cigarettes smoked per day among smokers. The association between cigarettes smoked per day and body-mass index was non-significant. Compared with light smokers, the adjusted odds ratio (OR) for abdominal obesity in men was 1.28 (0.78-2.10) for moderate smokers and 1.94 (1.15-3.27) for heavy smokers (P=0.03 for trend), and 1.07 (0.72-1.58) and 2.15 (1.26-3.64) in female moderate and heavy smokers, respectively (P<0.01 for trend). Compared with light smokers, the OR for excess body fat in men was 1.05 (95% CI: 0.58-1.92) for moderate smokers and 1.15 (0.60-2.20) for heavy smokers (P=0.75 for trend) and 1.34 (0.89-2.00) and 2.11 (1.25-3.57), respectively in women (P=0.07 for trend). CONCLUSION: Among smokers, cigarettes smoked per day were positively associated with central fat accumulation, particularly in women.

Reproducibility and within-day variability of body fat measurements using segmental bipolar bioelectrical impedance in women

BACKGROUND AND AIMS: little is known regarding the reproducibility of body fat measuring devices; hence, we assessed the between and within-device reproducibility, and the within-day variability of body fat measurements. METHODS: body fat percentage was measured twice on seventeen female students aged between 18 and 20 with a body mass index of 21.9 ± 2.5 kg/m2 (mean ± SD) using seven bipolar bioelectrical impedance devices. Each participant was also measured each hour between 7:00 and 22:00. RESULTS: the correlation between first and second measurements was very high (Spearman r between 0.985 and 1.000, p<0.001), as well as between devices (Spearman r between 0.916 and 0.991, p<0.001). Repeated measurements analysis showed no differences were between devices (p=0.59) or readings (first vs. second: p=0.74). Conversely, significant differences were found between assessment periods throughout the day, measurements made in the morning being lower than those made in the afternoon (F test for repeated values= 6.58, p<0.001). CONCLUSIONS: the between and within-device reproducibility for measuring body fat is high, enabling the use of multiple devices in a single study. Conversely, small but significant changes in body fat measurements occur during the day, urging body fat measurements to be performed at fixed times.

Is lean body mass decreased after obesity treatment by adjustable gastric banding?

BACKGROUND: There is concern that surgically-induced weight loss in obese subjects is associated with a disproportionate decrease in lean body mass (LBM) and in skeletal muscle mass (SMM), a major constituent of LBM. To address this issue, 1) we measured total and regional body composition following gastric banding in a group of obese subjects, and 2) we compared these data to those of a non-surgical control group of similar age and body size. METHODS: Body composition was assessed by dual-energy X-ray absorptiometry (DEXA) before and after laparoscopic adjustable silicone gastric banding (LAGB) in 32 women (after 1 year: age 43.7+/-8.4 years, BMI 36.4+/-5.9 kg/m2, mean+/-SD), and in 117 control women (age 44.5+/-7.5 years; BMI 36.7+/-5.5 kg/m2) referred for non-surgical weight management, prior to weight loss. SMM was estimated using a published equation based on LBM of the extremities (appendicular LBM). RESULTS: 1 year after LAGB, body weight loss (-23.7+/-11.6 kg, P<10(-6)) was mainly due to decreased fat mass (-21.2+/-11.2 kg, P<10(-6)), and total LBM was modestly, although significantly, decreased (-2.1+/-4.2 kg, P=0.01). Appendicular LBM (-0.7+/-2.7 kg) and total SMM (-0.9+/-3.0 kg) were not significantly modified. None of the body composition variables was significantly decreased in weight-reduced subjects compared to the control group, especially appendicular LBM and total SMM. CONCLUSIONS: Results provide no evidence for a decrease in appendicular LBM and total SMM with weight loss following LAGB. Follow-up of these obese patients revealed a very favorable pattern of change in total and regional body composition, with preservation of muscle mass.

Total energy expenditure and patterns of activity in 8-10-year-old obese and nonobese children.

Total energy expenditure (TEE) and patterns of activity were measured by means of a heart rate (HR)-monitoring method in a group of 8-10-year-old children including 13 obese children (weight, 46 +/- 10 kg; fat mass: 32 +/- 9%) and 16 nonobese children (weight, 31 +/- 5 kg; fat mass, 18 +/- 5%). Time for sleeping was not statistically different in the two groups of children (596 +/- 33 vs. 582 +/- 43 min; p = NS). Obese children spent more time doing sedentary activities (400 +/- 129 vs. 295 +/- 127 min; p < 0.05) and less time in nonsedentary activities (449 +/- 126 vs. 563 +/- 135 min; p < 0.05) than nonobese children. Time spent in moderate or vigorous activity-i.e., time spent at a HR between 50% of the maximal O2 uptake (peak VO2) and 70% peak VO2 (moderate) and at a HR > or = 70% peak VO2 (vigorous)-was not statistically different in obese and nonobese children (88 +/- 69 vs. 52 +/- 35 min and 20 +/- 21 vs. 16 +/- 13 min, respectively; p = NS). TEE was significantly higher in the obese group than in the nonobese group (9.46 +/- 1.40 vs. 7.51 +/- 1.67 MJ/day; p < 0.01). The energy expenditure for physical activity (plus thermogenesis) was significantly higher in the obese children (3.98 +/- 1.30 vs. 2.94 +/- 1.39 MJ/day; p < 0.05). The proportion of TEE daily devoted to physical activity (plus thermogenesis) was not significantly different in the two groups, as shown by the ratio between TEE and the postabsorptive metabolic rate (PMR): 1.72 +/- 0.25 obese vs 1.61 +/- 0.28 non-obese. In conclusion, in free-living conditions obese children have a higher TEE than do nonobese children, despite the greater time devoted to sedentary activities. The higher energy cost to perform weight-bearing activities as well as the higher absolute PMR of obese children help explain this apparent paradox.

The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysis.

Different outcomes of the effect of catechin-caffeine mixtures and caffeine-only supplementation on energy expenditure and fat oxidation have been reported in short-term studies. Therefore, a meta-analysis was conducted to elucidate whether catechin-caffeine mixtures and caffeine-only supplementation indeed increase thermogenesis and fat oxidation. First, English-language studies measuring daily energy expenditure and fat oxidation by means of respiration chambers after catechin-caffeine mixtures and caffeine-only supplementation were identified through PubMed. Six articles encompassing a total of 18 different conditions fitted the inclusion criteria. Second, results were aggregated using random/mixed-effects models and expressed in terms of the mean difference in 24 h energy expenditure and fat oxidation between the treatment and placebo conditions. Finally, the influence of moderators such as BMI and dosage on the results was examined as well. The catechin-caffeine mixtures and caffeine-only supplementation increased energy expenditure significantly over 24 h (428.0 kJ (4.7%); P < 0.001 and 429.1 kJ (4.8%); P < 0.001, respectively). However, 24 h fat oxidation was only increased by catechin-caffeine mixtures (12.2 g (16.0%); P < 0.02 and 9.5 g (12.4%); P = 0.11, respectively). A dose-response effect on 24 h energy expenditure and fat oxidation occurred with a mean increase of 0.53 kJ mg(-1) (P < 0.01) and 0.02 g mg(-1) (P < 0.05) for catechin-caffeine mixtures and 0.44 kJ mg(-1) (P < 0.001) and 0.01 g mg(-1) (P < 0.05) for caffeine-only. In conclusion, catechin-caffeine mixtures or a caffeine-only supplementation stimulates daily energy expenditure dose-dependently by 0.4-0.5 kJ mg(-1) administered. Compared with placebo, daily fat-oxidation was only significantly increased after catechin-caffeine mixtures ingestion.

Thin healthy women have a similar low bone mass to women with anorexia nervosa.

An association between anorexia nerviosa (AN) and low bone mass has been demonstrated. Bone loss associated with AN involves hormonal and nutritional impairments, though their exact contribution is not clearly established. We compared bone mass in AN patients with women of similar weight with no criteria for AN, and a third group of healthy, normal-weight, age-matched women. The study included forty-eight patients with AN, twenty-two healthy eumenorrhoeic women with low weight (LW group; BMI < 18.5 kg/m2) and twenty healthy women with BMI >18.5 kg/m2 (control group), all of similar age. We measured lean body mass, percentage fat mass, total bone mineral content (BMC) and bone mineral density in lumbar spine (BMD LS) and in total (tBMD). We measured anthropometric parameters, leptin and growth hormone. The control group had greater tBMD and BMD LS than the other groups, with no differences between the AN and LW groups. No differences were found in tBMD, BMD LS and total BMC between the restrictive (n 25) and binge-purge type (n 23) in AN patients. In AN, minimum weight (P = 0.002) and percentage fat mass (P = 0.02) explained BMD LS variation (r2 0.48) and minimum weight (r2 0.42; P = 0.002) for tBMD in stepwise regression analyses. In the LW group, BMI explained BMD LS (r2 0.72; P = 0.01) and tBMD (r2 0.57; P = 0.04). We concluded that patients with AN had similar BMD to healthy thin women. Anthropometric parameters could contribute more significantly than oestrogen deficiency in the achievement of peak bone mass in AN patients.

Reproducibility and within-day variability of body fat masurements using segmental bipolar bioelectrical impedance in women

Objective: to assess the between and within-device reproducibility, as well as within-day variability of body fat measurements. Methods: body fat percentage (%BF) was measured twice on seventeen female students aged between 18 and 20 with a body mass index of 21.9 22.6 kg/m2 (mean SD) using seven bipolar bioelectrical impedance devices (BF-306) according to the manufacturer's recommendations. Each student was also measured each hour between 7:00 and 22:00. Statistical analysis was conducted using a general linear model for repeated measurements. Results: the correlation between first and second measurements was very high (Pearson r between 0.985 and 1.000, p<0.001), as well as the correlation between devices (Pearson r between 0.986 and 0.999, all p<0.001). Repeated measurements analysis showed no differences were between devices (F test=0.83, p=0.59) or readings (first vs. second: F test=0.12, p=0.74). Conversely, significant differences were found between assessment periods throughout the day, measurements made in the morning being lower than those made in the afternoon. Assuming an overall daily average of 100 (based on all measurements), the values were 95.8 3.2 (mean SD) at 8:00 versus 101.3 3.0 at 20:00, corresponding to a mean change of 2.2 1.1 in %BF (F test for repeated values=6.58, p<0.001). Conclusions: the between and within-device reproducibility for measuring body fat is high, enabling the use of multiple devices in a single study. Conversely, small but significant changes in body fat measurements occur during the day, urging body fat measurements to be performed at fixed times.

Effect of weight reduction in moderately overweight patients on recorded ambulatory blood pressure and free cytosolic platelet calcium.

Although platelet cytosolic calcium has been shown to decrease during pharmacological treatment of hypertension, there is no evidence that cytosolic calcium also falls during a nonpharmacological reduction in blood pressure. To provide such evidence, we examined prospectively the relation between platelet cytosolic calcium and ambulatory blood pressure during weight reduction in moderately overweight (body mass index [BMI] greater than 25), mildly hypertensive individuals. The experimental group (responders: BMI reduction greater than 5%) consisted of 19 patients who lost 8.5 +/- 2.9 kg (mean +/- SD, p less than 0.05) during a 10-week hypocaloric diet, whereas the control group (nonresponders: BMI reduction less than 5%) consisted of 12 patients who showed no relevant change in body weight (-2.0 +/- 1.3 kg) during the same period of time. The moderate weight loss of the responders decreased blood pressure by 14/5 mm Hg (p less than 0.05), as measured by ambulatory monitoring, which renders a placebo effect unlikely. This nonpharmacological reduction in blood pressure was accompanied by a proportional 11% decrease (p less than 0.05) in platelet cytosolic calcium and also by significant (p less than 0.05) decreases in plasma catecholamines and serum cholesterol. These findings establish the concept of a nonpharmacological reduction in free cytosolic platelet calcium in humans and add further evidence suggesting a link between intracellular calcium homeostasis and blood pressure regulation.