Relationship between diet and mental health in children and adolescents: a systematic review

We systematically reviewed 12 epidemiological studies to determine whether an association exists between diet quality and patterns and mental health in children and adolescents; 9 explored the relationship using diet as the exposure, and 3 used mental health as the exposure. We found evidence of a significant, cross-sectional relationship between unhealthy dietary patterns and poorer mental health in children and adolescents. We observed a consistent trend for the relationship between good-quality diet and better mental health and some evidence for the reverse. When including only the 7 studies deemed to be of high methodological quality, all but 1 of these trends remained. Findings highlight the potential importance of the relationship between dietary patterns or quality and mental health early in the life span.

Lack of seasonal and moult-related stress modulation in an opportunistically breeding bird: the white-plumed honeyeater (Lichenostomus penicillatus).

In most vertebrate species, glucocorticoid levels and stress sensitivity vary in relation to season and life-history stage. In birds, baseline corticosterone (CORT) and stress sensitivity are typically highest while breeding and decrease substantially during moult. Because elevated CORT adversely affects protein synthesis, moult-related CORT suppression is thought to be necessary for forming high-quality feathers. Surprisingly, some passerine species lack moult-related CORT suppression, but these are distinguished by having slow rates of moult and being opportunistic breeders. We examined baseline and stress-induced CORT levels in an opportunistically breeding Australian passerine, the white-plumed honeyeater (Lichenostomus penicillatus). Although this species has a slower moult rate than high-latitiude breeders, it differs little from north-temperate passerines. Neither baseline nor stress-induced CORT levels varied with season (winter, spring or summer), sex or moult status in adult birds. While breeding tended to be highest in early spring through late summer, laparotomies revealed only limited reduction in testicular size in males the year round. In all but one sampling period, at least some females displayed follicular hierarchy. Breeding usually coincides with outbreaks of phytophagous insects, which can happen at any time of the year. This results in moult/breeding overlap when infestations occur in late spring or summer. The ability of this species to moult and breed at the same time while having breeding-levels of CORT demonstrates that CORT suppression is not a prerequisite for synthesis of high-quality feathers. An experimental design incorporating moulting and non-moulting phenotypes is suggested to test the functional significance of CORT suppression in other species.

All signals are not equal: acoustic signalling of individuality, sex and breeding status in a cooperative breeder

Repeated interactions between individuals in socially living animals select for the evolution of signals that convey information identifying individuals or categories of individuals, which may enable the discrimination of familiar versus unfamiliar individuals. Such information may help animals maximize their inclusive fitness by adjusting their own behaviour, allowing them to avoid conflict, preferentially direct help and/or ignore unreliable individuals. Acoustic signals in birds provide the potential to encode individual-specific information. We examined the degree to which individual identity, sex, breeding status, group membership and genetic relatedness were related to variability in six different call types, which occurred across a variety of different behavioural contexts in the apostlebird, Struthidea cinerea, a socially living and cooperatively breeding Australian passerine. We demonstrated that not all calls reflected the same extent of information. Of the six call types, call variation was related to individual identity in three call types, breeding status in two call types and sex and group relatedness in one call type. Finally, variation in two call types was not related to any of the measured variables. Our results suggest that some, but not all, acoustic signals in apostlebirds may be selected for individual distinctiveness between individuals and categories of individuals (male versus female, breeder versus nonbreeder), and these signals may be important in determining levels of cooperation and interaction between individuals in this cooperatively breeding society. © 2014 The Association for the Study of Animal Behaviour.

Winter foraging site fidelity of king penguins breeding at the Falkland Islands

Foraging site fidelity has profound consequences for individual fitness, population processes and the effectiveness of species conservation measures. Accordingly, quantifying site fidelity has become increasingly important in animal movement and habitat selection studies. To assess foraging site fidelity in king penguins (Aptenodytes patagonicus) breeding at the Falkland Islands (51.48°S, 57.83°W), we measured overlap in time spent in foraging areas (at a 0.1° × 0.1° grid resolution) between successive foraging trips and foraging route consistency during the crèche period. In total, 30 complete foraging trips from seven king penguins were recorded between April and October 2010. King penguins predominantly foraged on the highly productive Patagonian slope, to the north of the Falkland Islands [median foraging trip distance 213 km (SD = 215 km) and duration 12.8 days (SD = 14.7 days)]. Overlap in time spent in an area on consecutive foraging trips ranged between 2 and 73 % (mean 27 %, SD = 22 %). Bearing during the outbound portion of foraging trips was typically highly repeatable for individual birds, but foraging trip duration and distance were not. Travel during the outbound phase of foraging trips was consistent with the direction of the northward-flowing Falkland Current that may act as a directional cue or facilitate rapid transit to foraging areas. Flexibility in foraging trip distances and durations may be a response to changes in resource availability and changes in the energetic requirements of adults and chicks over an extended breeding cycle.

The impact of whole-of-diet interventions on depression and anxiety: a systematic review of randomised controlled trials

Non-pharmacological approaches to the treatment of depression and anxiety are of increasing importance, with emerging evidence supporting a role for lifestyle factors in the development of these disorders. Observational evidence supports a relationship between habitual diet quality and depression. Less is known about the causative effects of diet on mental health outcomes. Therefore a systematic review was undertaken of randomised controlled trials of dietary interventions that used depression and/or anxiety outcomes and sought to identify characteristics of programme success.

Different male vs. female breeding periodicity helps mitigate offspring sex ratio skews in sea turtles

 The implications of climate change for global biodiversity may be profound with those species with little capacity for adaptation being thought to be particularly vulnerable to warming. A classic case of groups for concern are those animals exhibiting temperature-dependent sex-determination (TSD), such as sea turtles, where climate warming may produce single sex populations and hence extinction. We show that, globally, female biased hatchling sex ratios dominate sea turtle populations (exceeding 3:1 in >50% records), which, at-a-glance, reiterates concerns for extinction. However, we also demonstrate that more frequent breeding by males, empirically shown by satellite tracking 23 individuals and supported by a generalized bio-energetic life history model, generates more balanced operational sex ratios (OSRs). Hence, concerns of increasingly skewed hatchling sex ratios and reduced population viability are less acute than previously thought for sea turtles. In fact, in some scenarios skewed hatchling sex ratios in groups with TSD may be adaptive to ensure optimum OSRs.

Understanding meal patterns: definitions, methodology and impact on nutrient intake and diet quality

Traditionally, nutrition research has focused on individual nutrients, and more recently dietary patterns. However, there has been relatively little focus on dietary intake at the level of a 'meal'. The purpose of the present paper was to review the literature on adults' meal patterns, including how meal patterns have previously been defined and their associations with nutrient intakes and diet quality. For this narrative literature review, a comprehensive search of electronic databases was undertaken to identify studies in adults aged ≥  19 years that have investigated meal patterns and their association with nutrient intakes and/or diet quality. To date, different approaches have been used to define meals with little investigation of how these definitions influence the characterisation of meal patterns. This review identified thirty-four and fourteen studies that have examined associations between adults' meals patterns, nutrient intakes and diet quality, respectively. Most studies defined meals using a participant-identified approach, but varied in the additional criteria used to determine individual meals, snacks and/or eating occasions. Studies also varied in the types of meal patterns, nutrients and diet quality indicators examined. The most consistent finding was an inverse association between skipping breakfast and diet quality. No consistent association was found for other meal patterns, and little research has examined how meal timing is associated with diet quality. In conclusion, an understanding of the influence of different meal definitions on the characterisation of meal patterns will facilitate the interpretation of the existing literature, and may provide guidance on the most appropriate definitions to use.

Natural selection for earlier male arrival to breeding grounds through direct and indirect effects in a migratory songbird

For migratory birds, the earlier arrival of males to breeding grounds is often expected to have fitness benefits. However, the selection differential on male arrival time has rarely been decomposed into the direct effect of male arrival and potential indirect effects through female traits. We measured the directional selection differential on male arrival time in the pied flycatcher (Ficedula hypoleuca) using data from 6 years and annual number of fledglings as the fitness proxy. Using structural equation modeling, we were able to take into account the temporal structure of the breeding cycle and the hierarchy between the examined traits. We found directional selection differentials for earlier male arrival date and earlier female laying date, as well as strong selection differential for larger clutch size. These selection differentials were due to direct selection only as indirect selection for these traits was nonsignificant. When decomposing the direct selection for earlier male arrival into direct and indirect effects, we discovered that it was almost exclusively due to the direct effect of male arrival date on fitness and not due to its indirect effects via female traits. In other words, we showed for the first time that there is a direct effect of male arrival date on fitness while accounting for those effects that are mediated by effects of the social partner. Our study thus indicates that natural selection directly favored earlier male arrival in this flycatcher population.

Employing sea-level rise scenarios to strategically select sea turtle nesting habitat important for long-term management at a temperate breeding area

Management strategies to protect endangered species primarily focus on safeguarding habitats currently perceived as important (due to high-density use, rarity or contribution to the biological cycle), rather than sites of future ecological importance. This discrepancy is particularly relevant for species inhabiting beaches and coastal areas that may be lost due to sea-level rise over the next 100 years through climate change. Here, we modelled four sea-level rise (SLR) scenarios (0.2, 0.6, 0.9 and 1.3 m) to determine the future vulnerability and viability of nesting habitat (six distinct nesting beaches totalling about 6 km in length) at a key loggerhead sea turtle (Caretta caretta) rookery (Zakynthos, Greece) in the Mediterranean. For each of the six nesting beaches, we identified (1) the area of beach currently used by turtles, (2) the area of the beach anticipated to become inundated under each SLR, (3) the area of beach anticipated to become unsuitable for nesting under each SLR, (4) the potential for habitat loss under the examined SLR, and (5) the extent to which the beaches may shift in relation to natural (i.e. cliffs) and artificial (i.e. beach front development) physical barriers. Even under the most conservative 0.2 m SLR scenario, about 38% (range: 31–48%) total nesting beach area would be lost, while an average 13% (range: 7–17%) current nesting beach area would be lost. About 4 km length of nesting habitat (representing 85% of nesting activity) would be lost under the 0.9 m scenario, because cliffs prevent landward beach migration. In comparison, while the other 2 km of beach (representing 15% nests) is also at high risk, it has the capacity for landward migration, because of an adjoining sand-dune system. Therefore, managers should strengthen actions on this latter area, as a climatically critical safeguard for future sea turtle nesting activity, in parallel to regularly assessing and revising measures on the current high-use nesting habitats of this important Mediterranean loggerhead population.

Lower protein-to-carbohydrate ratio in maternal diet is associated with higher childhood systolic blood pressure up to age four years

The prenatal environment can influence development of offspring blood pressure (BP), which tracks into adulthood. This prospective longitudinal study investigated whether maternal pregnancy dietary intake is associated with the development of child BP up to age four years. Data are from 129 mother-child dyads enrolled in the Women and Their Children's Health study. Maternal diet was assessed using a validated 74-item food frequency questionnaire at 18 to 24 weeks and 36 to 40 weeks, with a reference period of the previous three months. Child systolic and diastolic BP were measured at 3, 6, 9, 12, 24, 36 and 48 months, using an automated BP monitor. Using mixed-model regression analyses adjusted for childhood growth indices, pregnancy intakes of percentage of energy (E%) polyunsaturated fat (β coefficient 0.73; 95% CI 0.003, 1.45; p = 0.045), E% omega-6 fatty acids (β coefficient 0.89; 95% CI 0.09, 1.69; p = 0.03) and protein-to-carbohydrate (P:C) ratio (β coefficient -14.14; 95% CI -27.68, -0.60; p = 0.04) were associated with child systolic BP trajectory up to 4 years. Child systolic BP was greatest at low proportions of dietary protein (<16% of energy) and high carbohydrate (>40% of energy) intakes. There may be an ideal maternal macronutrient ratio associated with optimal infant BP. Maternal diet, which is potentially modifiable, may play an important role in influencing offspring risk of future hypertension.

Switching to a 10-day Mediterranean-style diet improves mood and cardiovascular function in a controlled crossover study

OBJECTIVES: Even short-term adherence to a Mediterranean-style diet may benefit aspects of psychological functioning. The aim of the present study was to assess the effects of switching to a 10-d Mediterranean-style diet on mood, cognition, and cardiovascular measures. METHODS: Using a crossover design, 24 women were randomly assigned to either the diet change (where they switched to a Mediterranean-style diet) or no diet change (normal diet) condition for 10 days before switching to the other condition for the same duration. Mood, cognition, and cardiovascular measures of blood pressure, blood flow velocity, and arterial stiffness were assessed at baseline and at the completion of the two diets (days 11 and 22). RESULTS: Independent of whether the Mediterranean-style diet was undertaken before or after the crossover, it was associated with significantly elevated contentment and alertness, and significantly reduced confusion. Additionally, aspects of cognition, such as memory recall, improved significantly as a result of switching to the Mediterranean-style diet. Regarding cardiovascular measures, there was a significant reduction in augmentation pressure associated with the Mediterranean-style diet intervention, but blood flow velocity through the common carotid artery did not change. CONCLUSIONS: This Mediterranean-style diet has the potential to enhance aspects of mood, cognition, and cardiovascular function in a young, healthy adult sample.

Clustering of diet, physical activity and sedentary behaviour among Australian children: cross-sectional and longitudinal associations with overweight and obesity

BACKGROUND/OBJECTIVES: Evidence suggests diet, physical activity (PA) and sedentary behaviour cluster together in children, but research supporting an association with overweight/obesity is equivocal. Furthermore, the stability of clusters over time is unknown. The aim of this study was to examine the clustering of diet, PA and sedentary behaviour in Australian children and cross-sectional and longitudinal associations with overweight/obesity. Stability of obesity-related clusters over 3-years was also examined. SUBJECTS/METHODS: Data were drawn from the baseline (T1: 2002/03) and follow-up waves (T2: 2005/06) of the Health Eating and Play Study. Parents of Australian children aged 5-6 (n=87) and 10-12 years (n=123) completed questionnaires. Children wore accelerometers and height and weight were measured. Obesity-related clusters were determined using K-medians cluster analysis. Multivariate regression models assessed cross-sectional and longitudinal associations between cluster membership, and BMI z-score and weight status. Kappa statistics assessed cluster stability over time. RESULTS: Three clusters, labelled 'most Healthy', 'Energy-dense (ED) consumers who watch TV' and 'high sedentary behaviour/low moderate-to-vigorous physical activity' were identified at baseline and at follow-up. No cross-sectional associations were found between cluster membership, and BMI z-score or weight status at baseline. Longitudinally, children in the 'ED consumers who watch TV' cluster had a higher odds of being overweight/obese at follow-up (OR=2.8; 95% CI: 1.1, 6.9; P<0.05). Tracking of cluster membership was fair to moderate in younger (K=0.24; P=0.0001) and older children (K=0.46; P<0.0001). CONCLUSIONS: This study identified an unhealthy cluster of TV viewing with ED food/drink consumption which predicted overweight/obesity in a small longitudinal sample of Australian children. Cluster stability was fair to moderate over three years and is a novel finding. Prospective research in larger samples is needed to examine how obesity-related clusters track over time and influence the development of overweight and obesity.International Journal of Obesity accepted article preview online, 24 April 2015. doi:10.1038/ijo.2015.66.

Associations of diet quality with health-related quality of life in older Australian men and women

This study investigated associations between diet quality measures and quality of life two years later. Adults 55-65 years participating in the Wellbeing, Eating and Exercise for a Long Life (WELL) study in Victoria, Australia (n = 1150 men and n = 1307 women) completed a postal survey including a 111-item food frequency questionnaire in 2010. Diet quality in 2010 was assessed via the dietary guideline index (DGI), recommended food score (RFS) and Mediterranean diet score (MDS). The RAND 36-item survey assessed health-related quality of life in 2012. Associations were assessed using logistic regression adjusted for covariates. In men, DGI and RFS were associated with better reported energy (OR = 1.79, CI: 1.25, 2.55 and OR = 1.56, CI: 1.11, 2.19 respectively), and DGI was additionally associated with better general health (OR = 1.54, 95% CI: 1.08, 2.20), and overall mental component summary scale (OR = 1.51, CI: 1.07, 2.15) in the fully adjusted model. In women, associations between two indices of diet quality (DGI, RFS) physical function (OR = 1.66, CI: 1.19, 2.31 and OR = 1.70, CI: 1.21, 2.37 respectively) and general health (OR = 1.83, CI: 1.32, 2.54 and OR = 1.54, CI: 1.11, 2.14 respectively) were observed. DGI was also associated with overall physical component summary score (OR = 1.56, CI: 1.12, 2.17). Additional associations between emotional wellbeing and DGI (OR = 1.40, CI: 1.01, 1.93) and RFS (OR = 1.44, CI: 1.04, 1.99), and MDS and energy (OR = 1.53, CI: 1.11, 2.10) were observed in the fully adjusted model, in women only. Older adults with better quality diets report better health-related quality of life, with additional associations with emotional wellbeing observed in women.

The association between diet quality and mental health during the perinatal period. A systematic review

BACKGROUND: While maternal nutrition during pregnancy is known to play a critical role in the health of both mother and offspring, the magnitude of this association has only recently been realized. Novel, epigenetic data suggest that maternal dietary intake has permanent phenotypic consequences for offspring, highlighting the potency of antenatal diet. To date, the relationship between poor antenatal diet and maternal mental health specifically, remains poorly understood. Therefore, we aimed to systematically review evidence that has examined associations between antenatal diet quality and the experience of depressive, anxiety and stress symptoms during the perinatal period.

METHODS: A search for peer-reviewed papers was conducted using Medline Complete, PsycINFO, CINAHL, Academic Search Premiere and Psychology and Behavioral Science Collection.

RESULTS: Nine studies (cohort = 4, cross-sectional = 5) published between 2005 and 2013 were eligible for inclusion in this review. A synthesis of findings revealed positive associations between poor quality and unhealthy diets and antenatal depressive and stress symptoms. Healthy diets were inversely associated with antenatal depressive and anxiety symptoms. Postnatal depressive symptoms demonstrated inconsistent results.

CONCLUSIONS: Given the paucity of research examining diet quality and mental health in women during the perinatal period, further sufficiently powered studies are urgently required to examine this association.

The association between socio-economic position and diet quality in Australian adults

Objective: We aimed to investigate the association between multiple measures of socio-economic position (SEP) and diet quality, using a diet quality index representing current national dietary guidelines, in the Australian adult population. Design: Cross-sectional study. Linear regression analyses were used to estimate the association between indicators of SEP (educational attainment, level of income and area-level disadvantage) and diet quality (measured using the Dietary Guideline Index (DGI)) in the total sample and stratified by sex and age (≤55 years and >55 years). Setting: A large randomly selected sample of the Australian adult population. Subjects: Australian adults (n 9296; aged ≥25 years) from the Australian Diabetes, Obesity and Lifestyle Study. Results: A higher level of educational attainment and income and a lower level of area-level disadvantage were significantly associated with a higher DGI score, across the gradient of SEP. The association between indicators of SEP and DGI score was consistently stronger among those aged ≤55 years compared with their older counterparts. The most disadvantaged group had a DGI score between 2 and 5 units lower (depending on the marker of SEP) compared with the group with the least disadvantage. Conclusions: A higher level of SEP was consistently associated with a higher level of diet quality for all indicators of SEP examined. In order to reduce socio-economic inequalities in diet quality, healthy eating initiatives need to act across the gradient of socio-economic disadvantage with a proportionate focus on those with greater socio-economic disadvantage.