Foraging ecology, fluctuating food availability and energetics of wintering brent geese

Changing energy requirements and dramatic shifts in food availability are major factors driving behaviour and distribution of herbivores. We investigate this in wintering East Canadian High Arctic light-bellied brent geese Branta bernicla hrota in Northern Ireland. They followed a sequential pattern of habitat use, feeding on intertidal Zostera spp. in autumn and early winter before moving to predominantly saltmarsh and farmland in late winter and early spring. Night-time feeding occurred throughout and made a considerable contribution to the birds' daily energy budget, at times accounting for > 50% of energy intake. Nocturnal feeding, however, is limited to the intertidal, possibly because of predation risk on terrestrial habitat, and increases with moonlight. The amount of Zostera spp., declined dramatically after the arrival of birds, predominantly, but not entirely, due to consumption by the birds. Birds gained fat reserves in the first 2 months but then this was dramatically lost as their major food source collapsed and their daily energy intake declined. Single birds consistently fared worse than paired birds and pairs with juveniles fared better than those without suggesting a benefit of having a family to compete for food. Many birds leave the Lough at this time of reduced Zostera spp. for other sea inlets in Ireland but some remain. Body condition of the latter gradually improved in early spring and reflected a heavy reliance on terrestrial habitats, particularly farmland, to meet the birds' daily energy requirements. However, even in the period immediately before migration to the breeding ground, the birds did not regain the amount of abdominal fatness observed in November. The dramatic changes in available food and requirements of the birds drive the major changes seen in foraging behaviour as the birds evade starvation in the wintering period.

The effect of increasing fruit and vegetable consumption on overall diet: a systematic review and meta-analysis

Increasing fruit and vegetable (FV) consumption is associated with reduced risk of major diseases. However, it is unclear if health benefits are related to increased micronutrient intake or to improvements in overall diet profile. This review aimed to assess if increasing FV consumption had an impact on diet profile. In the systematic review, twelve studies revealed increases in micronutrient intakes, whilst the meta-analysis confirmed macronutrient findings from the systematic review showing no significant difference between the intervention and control groups in energy (kcals) in seven studies (mean difference = 1 kcals [95% CI = -115, 117]; P = 0.98), significant decreases in total fat (% energy) in 5 studies (Mean difference = -4% [95% CI = -5, -3]; P = <0.00001) and significant increases in fibre in 6 studies (Mean difference = 5.36 grams [95% CI = 4, 7]; P = <0.00001) and total carbohydrate (% energy) in 4 studies (Mean = 4% [95% CI = 2, 5]; P = <0.00001). In conclusion, results indicate that increased FV consumption increases micronutrient, carbohydrate and fibre intakes and possibly reduces fat intake, with no overall effect on energy intake. Therefore health benefits may act through an improvement in overall diet profile alongside increased micronutrient intakes.

Environmental Challenges and Physiological Solutions: Comparative Energetic Daily Rhythms of Field Mice Populations from Different Ecosystems

Daily and seasonal variations in physiological characteristics of mammals can be considered adaptations to temporal habitat variables. Across different ecosystems, physiological adjustments are expected to be sensitive to different environmental signals such as changes in photoperiod, temperature or water and food availability; the relative importance of a particular signal being dependent on the ecosystem in question. Energy intake, oxygen consumption (VO) and body temperature (T) daily rhythms were compared between two populations of the broad-toothed field mouse Apodemus mystacinus, one from a Mediterranean and another from a sub-Alpine ecosystem. Mice were acclimated to short-day (SD) 'winter' and long-day (LD) 'summer' photoperiods under different levels of salinity simulating osmotic challenges. Mediterranean mice had higher VO values than sub-Alpine mice. In addition, mice exposed to short days had higher VO values when given water with a high salinity compared with mice exposed to long days. By comparison, across both populations, increasing salinity resulted in a decreased T in SD- but not in LD-mice. Thus, SD-mice may conserve energy by decreasing T during ('winter') conditions which are expected to be cool, whereas LD-mice might do the opposite and maintain a higher T during ('summer') conditions which are expected to be warm. LD-mice behaved to reduce energy expenditure, which might be considered a useful trait during 'summer' conditions. Overall, increasing salinity was a clear signal for Mediterranean-mice with resultant effects on VO and T daily rhythms but had less of an effect on sub-Alpine mice, which were more responsive to changes in photoperiod. Results provide an insight into how different populations respond physiologically to various environmental challenges.

Biomarkers in nutrition: new frontiers in research and application

Nutritional biomarkers-biochemical, functional, or clinical indices of nutrient intake, status, or functional effects--are needed to support evidence-based clinical guidance and effective health programs and policies related to food, nutrition, and health. Such indices can reveal information about biological or physiological responses to dietary behavior or pathogenic processes, and can be used to monitor responses to therapeutic interventions and to provide information on interindividual differences in response to diet and nutrition. Many nutritional biomarkers are available; yet there has been no formal mechanism to establish consensus regarding the optimal biomarkers for particular nutrients and applications.

Effect of a Web-Based Behavior Change Program on Weight Loss and Cardiovascular Risk Factors in Overweight and Obese Adults at High Risk of Developing Cardiovascular Disease:Randomized Controlled Trial

BACKGROUND: Web-based programs are a potential medium for supporting weight loss because of their accessibility and wide reach. Research is warranted to determine the shorter- and longer-term effects of these programs in relation to weight loss and other health outcomes.

OBJECTIVE: The aim was to evaluate the effects of a Web-based component of a weight loss service (Imperative Health) in an overweight/obese population at risk of cardiovascular disease (CVD) using a randomized controlled design and a true control group.

METHODS: A total of 65 overweight/obese adults at high risk of CVD were randomly allocated to 1 of 2 groups. Group 1 (n=32) was provided with the Web-based program, which supported positive dietary and physical activity changes and assisted in managing weight. Group 2 continued with their usual self-care (n=33). Assessments were conducted face-to-face. The primary outcome was between-group change in weight at 3 months. Secondary outcomes included between-group change in anthropometric measurements, blood pressure, lipid measurements, physical activity, and energy intake at 3, 6, and 12 months. Interviews were conducted to explore participants' views of the Web-based program.

RESULTS: Retention rates for the intervention and control groups at 3 months were 78% (25/32) vs 97% (32/33), at 6 months were 66% (21/32) vs 94% (31/33), and at 12 months were 53% (17/32) vs 88% (29/33). Intention-to-treat analysis, using baseline observation carried forward imputation method, revealed that the intervention group lost more weight relative to the control group at 3 months (mean -3.41, 95% CI -4.70 to -2.13 kg vs mean -0.52, 95% CI -1.55 to 0.52 kg, P<.001), at 6 months (mean -3.47, 95% CI -4.95 to -1.98 kg vs mean -0.81, 95% CI -2.23 to 0.61 kg, P=.02), but not at 12 months (mean -2.38, 95% CI -3.48 to -0.97 kg vs mean -1.80, 95% CI -3.15 to -0.44 kg, P=.77). More intervention group participants lost ≥5% of their baseline body weight at 3 months (34%, 11/32 vs 3%, 1/33, P<.001) and 6 months (41%, 13/32 vs 18%, 6/33, P=.047), but not at 12 months (22%, 7/32 vs 21%, 7/33, P=.95) versus control group. The intervention group showed improvements in total cholesterol, triglycerides, and adopted more positive dietary and physical activity behaviors for up to 3 months verus control; however, these improvements were not sustained.

CONCLUSIONS: Although the intervention group had high attrition levels, this study provides evidence that this Web-based program can be used to initiate clinically relevant weight loss and lower CVD risk up to 3-6 months based on the proportion of intervention group participants losing ≥5% of their body weight versus control group. It also highlights a need for augmenting Web-based programs with further interventions, such as in-person support to enhance engagement and maintain these changes.

Nutrição clínica aplicada à alimentação escolar

Relatório de estágio de mestrado, Nutrição Clínica, Universidade de Lisboa, Faculdade de Medicina, 2015

The impact of oligofructose on stimulation of gut hormones, appetite regulation and adiposity

Objective: To investigate the effect of nutrient stimulation of gut hormones by oligofructose supplementation on appetite, energy intake (EI), body weight (BW) and adiposity in overweight and obese volunteers. Methods: In a parallel, single-blind and placebo-controlled study, 22 healthy overweight and obese volunteers were randomly allocated to receive 30 g day−1 oligofructose or cellulose for 6 weeks following a 2-week run-in. Subjective appetite and side effect scores, breath hydrogen, serum short chain fatty acids (SCFAs), plasma gut hormones, glucose and insulin concentrations, EI, BW and adiposity were quantified at baseline and post-supplementation. Results: Oligofructose increased breath hydrogen (P < 0.0001), late acetate concentrations (P = 0.024), tended to increase total area under the curve (tAUC)420mins peptide YY (PYY) (P = 0.056) and reduced tAUC450mins hunger (P = 0.034) and motivation to eat (P = 0.013) when compared with cellulose. However, there was no significant difference between the groups in other parameters although within group analyses showed an increase in glucagon-like peptide 1 (GLP-1) (P = 0.006) in the cellulose group and a decrease in EI during ad libitum meal in both groups. Conclusions: Oligofructose increased plasma PYY concentrations and suppressed appetite, while cellulose increased GLP-1 concentrations. EI decreased in both groups. However, these positive effects did not translate into changes in BW or adiposity.

Effects of targeted delivery of propionate to the human colon on appetite regulation, body weight maintenance and adiposity in overweight adults.

OBJECTIVE: The colonic microbiota ferment dietary fibres, producing short chain fatty acids. Recent evidence suggests that the short chain fatty acid propionate may play an important role in appetite regulation. We hypothesised that colonic delivery of propionate would increase peptide YY (PYY) and glucagon like peptide-1 (GLP-1) secretion in humans, and reduce energy intake and weight gain in overweight adults. DESIGN: To investigate whether propionate promotes PYY and GLP-1 secretion, a primary cultured human colonic cell model was developed. To deliver propionate specifically to the colon, we developed a novel inulin-propionate ester. An acute randomised, controlled cross-over study was used to assess the effects of this inulin-propionate ester on energy intake and plasma PYY and GLP-1 concentrations. The long-term effects of inulin-propionate ester on weight gain were subsequently assessed in a randomised, controlled 24-week study involving 60 overweight adults. RESULTS: Propionate significantly stimulated the release of PYY and GLP-1 from human colonic cells. Acute ingestion of 10 g inulin-propionate ester significantly increased postprandial plasma PYY and GLP-1 and reduced energy intake. Over 24 weeks, 10 g/day inulin-propionate ester supplementation significantly reduced weight gain, intra-abdominal adipose tissue distribution, intrahepatocellular lipid content and prevented the deterioration in insulin sensitivity observed in the inulin-control group. CONCLUSIONS: These data demonstrate for the first time that increasing colonic propionate prevents weight gain in overweight adult humans.

Three essays in risky behaviors

A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

Alimentação e estado nutricional de grupos da população do concelho de Lisboa

RESUMO - Objectivo: descrever o estado nutricional e o padrão alimentar de grupos da população de Lisboa. Delineamento, locais e participantes: estudo transversal do estado nutricional e do padrão alimentar de homens com 38 anos e mulheres e homens com 50-65 anos que vivem na freguesia do Lumiar, do concelho de Lisboa; estudo transversal dos hábitos alimentares e do estado nutricional de adolescentes com 12 a 19 anos estudantes de escolas secundárias de Lisboa; estudo transversal da excreção de sódio em urina de 24 horas de rapazes de 7 a 8 anos de escolas primárias do Lumiar. Métodos: o estado nutricional foi avaliado com metodologias padronizadas tal como propostas pela OMS. A ingestão alimentar foi medida pelo método das 24 horas anteriores no primeiro estudo e pelo método da história alimentar no segundo estudo. Resultados: nas crianças, a excreção urinária de sódio foi uma das mais altas da Europa. Nos adolescentes, a prevalência de excesso de peso/obesidade foi de 19% nos rapazes e 16% nas raparigas. 16% dos adolescentes não tomam pequeno-almoço, mas mais de 30% comem bolos a meio da manhã. A proporção de adolescentes com uma ingestão diária de certos alimentos é de 44% para guloseimas, 43% para bolos, 29% para refrigerantes e 16% para chocolates e gelados. Por outro lado, a frequência de ingestão diária de fruta e produtos hortícolas é baixa, principalmente nos adolescentes de menor nível sócio-económico. Nos adultos, 57% dos homens com 38 anos e 80% e 74% dos homens e mulheres com 50-65 anos, respectivamente, têm excesso de peso ou obesidade. A hipertensão arterial foi detectada em mais de 20% dos homens jovens e a sua prevalência aumenta com a idade. Foi observado um colesterol sérico superior a 200 mg/dL em perto de metade dos adultos e maior do que 240 mg/dL em 28% dos homens com 38 anos, em 24% dos homens com 50-65 anos e 44% das mulheres do mesmo grupo etário. 20% dos adultos jovens têm colesterol HDL inferior a 35 mg/dL, mais do que um terço são fumadores e a ingestão de álcool representa 13% da sua ingestão calórica total. Conclusões: foram observados estilos de vida não saudáveis, nomeadamente padrões alimentares não equilibrados, uma elevada prevalência de obesidade, hipertensão e dislipidemias, e, por isso, uma percentagem relativamente elevada da população de Lisboa tem um risco elevado de doenças cárdio-vasculares e outras doenças crónicas, bem como de morte prematura.

Food habits and sport activity during adolescence: differences between athletic and non-athletic teenagers in Switzerland.

OBJECTIVE: To describe food habits and dietary intakes of athletic and non-athletic adolescents in Switzerland. SETTING: College, high schools and professional centers in the Swiss canton of Vaud. METHOD: A total of 3,540 subjects aged 9-19 y answered a self-reported anonymous questionnaire to assess lifestyles, physical plus sports activity and food habits. Within this sample, a subgroup of 246 subjects aged 11-15 also participated in an in-depth ancillary study including a 3 day dietary record completed by an interview with a dietician. RESULTS: More boys than girls reported engaging in regular sports activities (P<0.001). Adolescent food habits are quite traditional: up to 15 y, most of the respondents have a breakfast and eat at least two hot meals a day, the percentages decreasing thereafter. Snacking is widespread among adolescents (60-80% in the morning, 80-90% in the afternoon). Food habits among athletic adolescents are healthier and also are perceived as such in a higher proportion. Among athletic adolescents, consumption frequency is higher for dairy products and ready to eat (RTE) cereals, for fruit, fruit juices and salad (P<0.05 at least). Thus the athletic adolescent's food brings more micronutrients than the diet of their non-athletic counterparts. Within the subgroup (ancillary study), mean energy intake corresponds to requirements for age/gender group. CONCLUSIONS: Athletic adolescents display healthier food habits than non-athletic adolescents: this result supports the idea that healthy behavior tends to cluster and suggests that prevention programs among this age group should target simultaneously both sports activity and food habits.

High fat versus high carbohydrate nutritional supplementation: a one year trial in stunted rural Gambian children.

OBJECTIVE: The study tests the hypothesis that a low daily fat intake may induce a negative fat balance and impair catch-up growth in stunted children between 3 and 9y of age. DESIGN: Randomized case-control study. SETTING: Three rural villages of the West Kiang District, The Gambia. SUBJECTS: Three groups of 30 stunted but not wasted children (height for age z-score < or = -2.0, weight for height z-score > or = -2.0) 3-9 y of age were selected by anthropometric survey. Groups were matched for age, sex, village, degree of stunting and season. INTERVENTION: Two groups were randomly assigned to be supplemented five days a week for one year with either a high fat (n = 29) or a high carbohydrate biscuit (n = 30) each containing approximately 1600 kJ. The third group was a non supplemented control group (n = 29). Growth, nutritional status, dietary intake, resting energy expenditure and morbidity were compared. RESULTS: Neither the high fat nor the high carbohydrate supplement had an effect on weight or height gain. The high fat supplement did slightly increase adipose tissue mass. There was no effect of supplementation on resting energy expenditure or morbidity. In addition, the annual growth rate was not associated with a morbidity score. CONCLUSIONS: Results show that neither a high fat nor a high carbohydrate supplement given during 12 months to stunted Gambian children induced catch-up growth. The authors suggest that an adverse effect of the environment on catch-up growth persists despite the nutritional interventions.

Measurement of 13CO2 in expired air as an index of compliance to a high carbohydrate diet naturally enriched in 13C.

The aim of this study was to determine whether breath 13CO2 measurements could be used to assess the compliance to a diet containing carbohydrates naturally enriched in 13C. The study was divided into two periods: Period 1 (baseline of 4 days) with low 13C/12C ratio carbohydrates. Period 2 (5 days) isocaloric diet with a high 13C/12C ratio (corn, cane sugar, pineapple, millet) carbohydrates. Measurements were made of respiratory gas exchange by indirect calorimetry, urinary nitrogen excretion and breath 13CO2 every morning in post-absorptive conditions, both in resting state and during a 45-min low intensity exercise (walking on a treadmill). The subjects were 10 healthy lean women (BMI 20.4 +/- 1.7 kg/m2, % body fat 24.4 +/- 1.3%), the 13C enrichment of oxidized carbohydrate and breath 13CO2 were compared to the enrichment of exogenous dietary carbohydrates. At rest the enrichment of oxidized carbohydrate increased significantly after one day of 13C carbohydrate enriched diet and reached a steady value (103 +/- 16%) similar to the enrichment of exogenous carbohydrates. During exercise, the 13C enrichment of oxidized carbohydrate remained significantly lower (68 +/- 17%) than that of dietary carbohydrates. The compliance to a diet with a high content of carbohydrates naturally enriched in 13C may be assessed from the measurement of breath 13CO2 enrichment combined with respiratory gas exchange in resting, postabsorptive conditions.

Eating habits of preschool children with high migrant status in Switzerland according to a new food frequency questionnaire.

Assessment of eating habits in young children from multicultural backgrounds has seldom been conducted. Our objectives were to study the reproducibility and the results of a food frequency questionnaire (FFQ) developed to assess changes in eating habits of preschool children with a high migrant population, in the context of a multidisciplinary multilevel lifestyle intervention. Three kindergarten classes (53% from migrant backgrounds) in French-speaking Switzerland were randomly selected and included 16 girls and 28 boys (mean age +/- SD, 5.4 +/- 0.7 years). The FFQ was filled out twice within a 4-week interval by the parents. Spearman rank correlations between the first and the second FFQ for the 39 items of the food questions were as follows: low (r < 0.50) for 8 (7 P < .05 and 1 nonsignificant), moderate (0.50 <or= r < 0.70) for 22 (all P < .01), and high (r >or= 0.70) for 9 (all P < .01). In addition, 28 of 39 intraclass correlation coefficients were high (>0.50, all P < .01). Eighty-six percent of the children ate breakfast at home daily, but only 67% had lunch at home. The percentages of children eating at least once a week in front of the TV were as follows: 50% for breakfast, 33% for lunch, 38% for dinner, and 48% for snacks. Forty percent of children asked their parents to buy food previously seen in advertisements and ate fast food between once a week and once a month. Children generally consumed foods with a high-energy content. The FFQ yielded good test-retest reproducibility for most items of the food questions and gave relevant findings about the eating habits of preschool children in areas with a high migrant population.

Fructose toxicity: is the science ready for public health actions?

PURPOSE OF REVIEW: The assumption that fructose may be toxic and involved in the pathogenesis of noncommunicable diseases such as obesity, diabetes mellitus, dyslipidemia, and even cancer has resulted in the call for public health action, such as introducing taxes on sweetened beverages. This review evaluates the scientific basis for such action. RECENT FINDINGS: Although some studies hint towards some potential adverse effects of excessive fructose consumption especially when combined with excess energy intake, the results from clinical trials do not support a significant detrimental effect of fructose on metabolic health when consumed as part of a weight-maintaining diet in amounts consistent with the average-estimated fructose consumption in Western countries. However, definitive studies are missing. SUMMARY: Public health policies to eliminate or limit fructose in the diet should be considered premature. Instead, efforts should be made to promote a healthy lifestyle that includes physical activity and nutritious foods while avoiding intake of excess calories until solid evidence to support action against fructose is available. Public health is almost certainly to benefit more from policies that are aimed at promoting what is known to be good than from policies that are prohibiting what is not (yet) known to be bad.