E. Leigh Gibson

Stress and Adiposity: A Meta-Analysis of Longitudinal Studies

Psychosocial stress has been strongly implicated in the biology of adiposity but epidemiological studies have produced inconsistent results. The aim of this analysis was to bring together results from published, longitudinal, prospective studies examining associations between psychosocial stress and objectively measured adiposity in a meta‐analysis. Searches were conducted on Medline, PsycINFO, Web of Science, and PubMed (to January 2009) and reference lists from relevant articles were examined. Prospective studies relating psychosocial stress (general life stress (including caregiver stress), work stress) to BMI, body fat, body weight, waist circumference, or waist‐to‐hip ratio were included. Analyses from 14 cohorts were collated and evaluated. There was no significant heterogeneity, no evidence of publication bias, and no association between study quality and outcomes. The majority of analyses found no significant relationship between stress and adiposity (69%), but among those with significant effects, more found positive than negative associations (25 vs. 6%). Combining results in a meta‐analysis showed that stress was associated with increasing adiposity (r = 0.014; confidence interval (CI) = 0.002–0.025, P < 0.05). Effects were stronger for men than women, in analyses with longer rather than shorter follow‐ups, and in better quality studies. We conclude that psychosocial stress is a risk factor for weight gain but effects are very small. Variability across studies indicates there are moderating variables to be elucidated.

Neuroendocrine and cardiovascular correlates of positive affect measured by ecological momentary assessment and by questionnaire

The relationships between positive affect, salivary cortisol over the day, and cardiovascular responses to laboratory mental stress tests, were assessed in 72 healthy non-smoking men (mean age 33.6+/-8.8 years). Positive affect was measured by aggregating ecological momentary assessments (EMA) of happiness obtained at four times on each of 2 working days, and by questionnaire using the Positive and Negative Affect Schedule (PANAS). Saliva was sampled on 2 days, on waking, 30 and 60 min later, and four other times over the day. Blood pressure and heart rate responses to speech and mirror tracing tasks were measured over two sessions 4 weeks apart. Data were analysed using regression of positive affect on biology adjusting for age, body mass and negative affect, with additional adjustment for time of waking in cortisol analyses and for work stress in cardiovascular analyses. EMA positive affect was inversely associated with cortisol early in the day and with the cortisol increase after waking, controlling for age, body mass index, and negative affect (P=0.012). There was no relationship between PANAS positive affect and cortisol, or between EMA positive affect and cortisol later in the day. Diastolic pressure recovery post-stress was more rapid among participants with high positive affect (P=0.022) and with lower systolic pressure throughout the stress sessions, after controlling for covariates including negative affect. PANAS positive affect was also inversely associated with systolic pressure, but not with diastolic stress or heart rate. We conclude that positive affect is related to biological responses in the laboratory and everyday life that may be health protective. Effects were substantially stronger when positive affect was assessed by aggregating EMA samples than with questionnaire measures.

Nutritional influences on cognitive function: mechanisms of susceptibility

The impact of nutritional variation, within populations not overtly malnourished, on cognitive function and arousal is considered. The emphasis is on susceptibility to acute effects of meals and glucose loads, and chronic effects of dieting, on mental performance, and effects of cholesterol and vitamin levels on cognitive impairment. New developments in understanding dietary influences on neurohormonal systems, and their implications for cognition and affect, allow reinterpretation of both earlier and recent findings. Evidence for a detrimental effect of omitting a meal on cognitive performance remains equivocal: from the outset, idiosyncrasy has prevailed. Yet, for young and nutritionally vulnerable children, breakfast is more likely to benefit than hinder performance. For nutrient composition, despite inconsistencies, some cautious predictions can be made. Acutely, carbohydrate-rich-protein-poor meals can be sedating and anxiolytic; by comparison, protein-rich meals may be arousing, improving reaction time but also increasing unfocused vigilance. Fat-rich meals can lead to a decline in alertness, especially where they differ from habitual fat intake. These acute effects may vary with time of day and nutritional status. Chronically, protein-rich diets have been associated with decreased positive and increased negative affect relative to carbohydrate-rich diets. Probable mechanisms include diet-induced changes in monoamine, especially serotoninergic neurotransmitter activity, and functioning of the hypothalamic pituitary adrenal axis. Effects are interpreted in the context of individual traits and susceptibility to challenging, even stressful, tests of performance. Preoccupation with dieting may impair cognition by interfering with working memory capacity, independently of nutritional status. The change in cognitive performance after administration of glucose, and other foods, may depend on the level of sympathetic activation, glucocorticoid secretion, and pancreatic beta-cell function, rather than simple fuelling of neural activity. Thus, outcomes can be predicted by vulnerability in coping with stressful challenges, interacting with nutritional history and neuroendocrine status. Functioning of such systems may be susceptible to dietary influences on neural membrane fluidity, and vitamin-dependent cerebrovascular health, with cognitive vulnerability increasing with age.

A High Omega-3 Fatty Acid Multinutrient Supplement Benefits Cognition and Mobility in Older Women: A Randomized, Double-blind, Placebo-controlled Pilot Study

Background. Mobility is a key determinant of frailty in older persons, and a variety of dietary factors, such as the omega-3 fatty acid docosahexaenoic acid (DHA), are positively associated with decreased frailty and improved mobility and cognition in older persons. Methods. The effects of a multinutrient supplement on mobility and cognition were assessed in postmenopausal women (60–84 years). Participants received either Efalex Active 50+ (1g DHA, 160mg eicosapentaenoic acid, 240mg Ginkgo biloba, 60mg phosphatidylserine, 20mg d-α tocopherol, 1mg folic acid, and 20 µg vitamin B12 per day; N = 15) or placebo (N = 12) for 6 months. Mobility was assessed by VICON 9 motion capture camera system synchronized with Kistler force plates, cognitive performance by computerized cognitive function tests, and blood fatty acid levels by pin-prick analysis. Results. Significant effects of treatment were seen in two of the four cognitive tests, with shorter mean latencies in a motor screening task (p < .05) and more words remembered (p < .03), and one of the three primary mobility measures with improved habitual walking speed (p < .05). Compared with the placebo group, supplementation also resulted in significantly higher blood DHA levels (p < .02). Conclusions. In this pilot study, multinutrient supplementation improved cognition and mobility in able older females at clinically relevant levels, suggesting a potential role in reducing the decline to frailty.

Understanding Food Fussiness and Its Implications for Food Choice, Health, Weight and Interventions in Young Children: The Impact of Professor Jane Wardle

Purpose of ReviewThis review examines the concepts of fussy eating and food neophobia in the context of key determinants of the development of children’s food preferences. We discuss the evidence for genetic versus parental and other environmental influences on the ontogeny of these behavioural traits and the implications of current knowledge for interventions that attempt to lessen the impact of these traits on children’s diets. Finally, we consider whether these traits increase the risk of a child becoming obese, or alternatively, underweight and malnourished.Recent FindingsFussy eating and neophobia are related concepts with both genetic and environmental aetiologies. Parent-child correlations and heritability estimates are moderate to high for both traits, but aspects of the family environment remain influential in young children, although no longer in young adults. Parental strategies based around repeat tasting opportunities can improve acceptance of disliked foods in even the fussiest children. Fussy eating and neophobia are not risk factors for obesity but could limit growth in severe cases.SummaryFussy eating and food neophobia are common concerns for parents, though health risks are low. Dissemination of evidence-based strategies to parents that can encourage a more varied diet in young children would be helpful.

The importance of nutrition in aiding recovery from substance use disorders: A review

BACKGROUND Nutrition is a prerequisite for health; yet, there is no special nutritional assessment or guidance for drug and alcohol dependent individuals, despite the fact that their food consumption is often very limited, risking malnutrition. Further, the premise is examined that malnutrition may promote drug seeking and impede recovery from substance use disorders (SUD). METHOD A narrative review addressed the relationship between substance use disorders and nutrition, including evidence for malnutrition, as well as their impact on metabolism and appetite regulation. The implications of the biopsychology of addiction and appetite for understanding the role of nutrition in SUD were also considered. RESULTS The literature overwhelmingly finds that subjects with alcohol use disorder (AUD) and drug use disorder (DUD) typically suffer from nutrient deficiencies. These nutrient deficiencies may be complicit in the alcoholic myopathy, osteopenia and osteoporosis, and mood disorders including anxiety and depression, observed in AUD and DUD. These same individuals have also been found to have altered body composition and altered hormonal metabolic regulators. Additionally, brain processes fundamental for survival are stimulated both by food, particularly sweet foods, and by substances of abuse, with evidence supporting confusion (addiction transfer) when recovering from SUD between cravings for a substance and craving for food. CONCLUSION Poor nutritional status in AUD and DUD severely impacts their physical and psychological health, which may impede their ability to resist substances of abuse and recover their health. This review contributes to a better understanding of interventions that could best support individuals with substance use disorders.

Differences in Knowledge, Stress, Sensation Seeking and Locus of Control Linked to Dietary Adherence In Hemodialysis Patients

Patients with chronic kidney disease (CKD) often require regular hemodialysis (HD) to prolong life. However, between HD sessions, patients have to restrict their diets carefully to avoid excess accumulation of potassium, phosphate, sodium, and fluid, which their diseased kidneys can no longer regulate. Failure to adhere to their renal dietary regimes can be fatal; nevertheless, non-adherence is common, and yet little is known about the psychological variables that might predict this dietary behavior. Thus, this study aimed to assess whether dietary adherence might be affected by a variety of psychological factors including stress, personality, and health locus of control, as well as dietary knowledge, in chronic HD patients. Fifty-one patients (30 men; age range 25–85) who had undergone HD for at least 3 months and had been asked to restrict at least one of potassium, phosphate or fluid, were recruited from a hospital renal unit. Measures of adherence to each of potassium, phosphate, and fluid were derived from standard criteria for these physiological indices in renal patients. Knowledge of food/drink sources of these dietary factors, and their medical implications in relation to HD and CKD were assessed by a bespoke questionnaire. Psychological factors including stress, personality and health locus of control beliefs were measured by standardized questionnaires. Having to restrict a particular nutrient was associated with better knowledge of both food sources and medical complications for that nutrient; however, greater dietary knowledge was not linked to adherence, and knowledge of medical complications tended to be associated with poorer adherence to potassium and phosphate levels. Adherence to these two nutrient requirements was also associated with lower reported stress in the past week. Adherence was associated with differences in locus of control: these differences varied across indices although there was a tendency to believe in external loci. For potassium, phosphate, and fluid restriction, adherers were less likely to be sensation seekers but did not differ from non-adherers on impulsivity, anxiety sensitivity, or hopelessness. In conclusion, the links between dietary adherence and stress, locus of control and personality suggests that screening for such psychological factors may assist in managing adherence in HD patients.

A prebiotic intervention study in children with autism spectrum disorders (ASDs)

BackgroundDifferent dietary approaches, such as gluten and casein free diets, or the use of probiotics and prebiotics have been suggested in autistic spectrum disorders in order to reduce gastrointestinal (GI) disturbances. GI symptoms are of particular interest in this population due to prevalence and correlation with the severity of behavioural traits. Nowadays, there is lack of strong evidence about the effect of dietary interventions on these problems, particularly prebiotics. Therefore, we assessed the impact of exclusion diets and a 6-week Bimuno® galactooligosaccharide (B-GOS®) prebiotic intervention in 30 autistic children.ResultsThe results showed that children on exclusion diets reported significantly lower scores of abdominal pain and bowel movement, as well as lower abundance of Bifidobacterium spp. and Veillonellaceae family, but higher presence of Faecalibacterium prausnitzii and Bacteroides spp. In addition, significant correlations were found between bacterial populations and faecal amino acids in this group, compared to children following an unrestricted diet. Following B-GOS® intervention, we observed improvements in anti-social behaviour, significant increase of Lachnospiraceae family, and significant changes in faecal and urine metabolites.ConclusionsTo our knowledge, this is the first study where the effect of exclusion diets and prebiotics has been evaluated in autism, showing potential beneficial effects. A combined dietary approach resulted in significant changes in gut microbiota composition and metabolism suggesting that multiple interventions might be more relevant for the improvement of these aspects as well as psychological traits.Trial registrationNCT02720900; registered in November 2015.