Carotenoid colour as a cue to health in human skin

Carotenoids are red-yellow plant based pigments. When consumed, they contribute to human skin yellowness which in turn is perceived as healthy and attractive looking. In many non-primate species, carotenoids colour sexually selected ornaments, signalling health. This thesis explores the relationship between skin yellowness and aspects of human health to test the hypothesis that carotenoid colouration of skin acts as a cue to health beyond diet. Chapter 2 presents a demonstration that a modest change in carotenoid intake can lead to a favourable change in appearance. Chapter 3 investigates the relationship between skin yellowness and a number of health related risk factors. Findings show that that psychological stress varies with skin yellowness (independent of fruit and vegetable intake) both between and within participants. Chapter 4 investigates the relationship between prior symptoms of infectious illness (e.g. cold and flus); finding that symptoms experienced during the prior eight weeks are related to skin yellowness between subjects and also within (marginally). More recent symptoms of illness (i.e. the prior week) were not reflected in skin yellowness. The final empirical chapter explores skin colour and plasma carotenoid changes with experimentally induced sickness. Plasma carotenoids were found to reflect baseline skin yellowness and showed a reduction in response to sickness but this reduction was not reflected in skin yellowness. Skin colour did change in a manner consistent with changes in blood perfusion and oxygenation status. A follow-up perceptual study confirmed that this change can reliably inform judgements of health. Taken together, findings suggest that skin yellowness is related to aspects of health beyond diet (i.e. psychological stress and prior illness) on a timescale of weeks but not days; likely reflecting the time taken for carotenoids to reach the skin. Theoretically, findings support the hypothesis that carotenoid colouration of human skin is a cue to health

Tracking biases : an update to the validity and reliability of alcohol retail sales data for estimating population consumption in Scotland

Purchase of the sales data was funded by the Scottish Government as part of the wider Monitoring and Evaluating Scotland's Alcohol Strategy portfolio of studies. Funding to pay the Open Access publication charges for this article was provided by NHS Health Scotland.Aims: To highlight the importance of monitoring biases when using retail sales data to estimate population alcohol consumption. Methods: Previously, we identified and where possible quantified sources of bias that may lead to under- or overestimation of alcohol consumption in Scotland. Here, we update findings by using more recent data and by quantifying emergent biases. Results: Underestimation resulting from the net effect of biases on population consumption in Scotland increased from -4% in 2010 to -7% in 2013. Conclusion: Biases that might impact on the validity and reliability of sales data when estimating population consumption should be routinely monitored and updated.Publisher PDFPeer reviewe

Computational time-of-flight diffuse optical tomography

Imaging through a strongly diffusive medium remains an outstanding challenge in particular in association with applications in biological and medical imaging. Here we propose a method based on a single-photon time-of-flight camera that allows, in combination with computational processing of the spatial and full temporal photon distribution data, to image an object embedded inside a strongly diffusive medium over more than 80 transport mean free paths. The technique is contactless and requires one second acquisition times thus allowing Hz frame rate imaging. The imaging depth corresponds to several cm of human tissue and allows one to perform deep-body imaging, here demonstrated as a proof-of-principle.Comment: 8 page

Visualisation-centred interventions in the healthcare-associated infections field: an integrative review.

Introduction: Within educational and practice based interventions to help address healthcare-associated infections (HAIs), visualisations are often used as contributory or central components. However, these have not yet been the subject of systematic and comprehensive study. This ongoing review aims to synthesise the best available evidence on visualisation-centred interventions in terms of their types, how they are structured and applied, and their related effectiveness. Methods: Our search strategy prioritised identifying intervention-based studies with a central focus on visuals and HAIs, involving healthcare staff in clinical or learning settings, and incorporating evaluation. Following a search of 10 electronic databases (Web of Science, AMED, CINAHL, MEDLINE, PsycARTICLES, SocINDEX, SPORTDiscus, Art & Architecture Source, ERIC and American Doctoral Dissertations), 397 retrieved abstracts are being screened for relevance based on the above criteria. The CASP, QATSDD and QI-MQCS tools will be used to appraise the quality of selected studies and findings will be synthesised narratively and diagramatically. Results: Initial indications of findings suggest much diversity in the type of visualisations being implemented and in the designs of studies evaluating them. Our conference presentation will summarise the completed findings and will feature visual mappings of the nature, scope, effectiveness and quality of these interventions as a basis for participants' discussions. Conclusion: Visualisation-centred interventions offer potential to positively influence healthcare professionals towards prevention and control of HAIs, but their application should be imbued with a clear rationale and their impacts should be evaluated. This review will provide foundation for further research and developments within this dynamic field

Skin colour changes during experimentally-induced sickness

This project was supported by Swedish foundation for humanities and social sciences and a British Academy Wolfson Foundation Research Professorship grant. AH is supported by a studentship from the Biotechnology and Biological Sciences Research Council.Skin colour may be an important cue to detect sickness in humans but how skin colour changes with acute sickness is currently unknown. To determine possible colour changes, 22 healthy Caucasian participants were injected twice, once with lipopolysaccharide (LPS, at a dose of 2 ng/kg body weight) and once with placebo (saline), in a randomised cross-over design study. Skin colour across 3 arm and 3 face locations was recorded spectrophotometrically over a period of 8 hours in terms of lightness (L∗), redness (a∗) and yellowness (b∗) in a manner that is consistent with human colour perception. In addition, carotenoid status was assessed as we predicted that a decrease it skin yellowness would reflect a drop in skin carotenoids. We found an early change in skin colouration 1-3 hours post LPS injection with facial skin becoming lighter and less red whilst arm skin become darker but also less red and less yellow. The LPS injection also caused a drop in plasma carotenoids from 3 hours onwards. However, the timing of the carotenoid changes was not consistent with the skin colour changes suggesting that other mechanisms, such as a reduction of blood perfusion, oxygenation or composition. This is the first experimental study characterising skin colour associated with acute illness, and shows that changes occur early in the development of the sickness response. Colour changes may serve as a cue to health, prompting actions from others in terms of care-giving or disease avoidance. Specific mechanisms underlying these colour changes require further investigation.PostprintPeer reviewe

Savjetovanje ribarskih stručnjaka pri Glavnoj direkciji za slatkovodno ribarstvo

This work was supported by a British Academy Wolfson Professorship to DP (WRP/2008/87). AH was supported by a Eastbio BBSRC studentship.Colorful carotenoid ornaments are sexually selected signals of health in many species. In humans too, carotenoids could provide a perceptible cue to health as they impart an attractive yellow-orange color to skin. Increasing carotenoid pigmentation and skin yellowness is associated with increased fruit and vegetable intake, but whether other aspects of human health benefit skin color is unknown. Carotenoids, as antioxidants, help maintain oxidative balance but are expended in this role. Therefore, any health factor affecting oxidative balance could alter the quantity of carotenoids available to color skin. Exercise increases endogenous antioxidant capacity and consequently may decrease expenditure of carotenoids. Fitness could also raise skin carotenoids by lowering body fat (a source of oxidative stress). Here we investigate the relationship between skin color (measured spectrophotometrically), aerobic fitness (measured by estimating the maximum volume of oxygen that a person can use per unit of time, VO2 max), and body fat. In a cross-sectional design, we find that both higher aerobic fitness and lower body fat are predictors of skin yellowness, independent of each other and dietary fruit and vegetable intake. In a longitudinal design over 8 weeks, we found that increase in fitness and decrease in body fat were independently associated with an increase in skin yellowness. Change in self-reported stress and sleep were further predictors of skin yellowness indicating a more general relation between health and skin tone. Simulations of the skin color associated with higher fitness were found to appear healthier. Hence, our results suggest that increasing cardiovascular fitness and decreasing fat levels produce a healthier skin color. Such findings have repercussions for public health because improved attractiveness can provide an incentive for a healthier lifestyle, including exercise and weight regulation.Publisher PDFPeer reviewe