Ross David Whitehead

You Are What You Eat: Within-Subject Increases in Fruit and Vegetable Consumption Confer Beneficial Skin-Color Changes

Background Fruit and vegetable consumption and ingestion of carotenoids have been found to be associated with human skin-color (yellowness) in a recent cross-sectional study. This carotenoid-based coloration contributes beneficially to the appearance of health in humans and is held to be a sexually selected cue of condition in other species. Methodology and Principal Findings Here we investigate the effects of fruit and vegetable consumption on skin-color longitudinally to determine the magnitude and duration of diet change required to change skin-color perceptibly. Diet and skin-color were recorded at baseline and after three and six weeks, in a group of 35 individuals who were without makeup, self-tanning agents and/or recent intensive UV exposure. Six-week changes in fruit and vegetable consumption were significantly correlated with changes in skin redness and yellowness over this period, and diet-linked skin reflectance changes were significantly associated with the spectral absorption of carotenoids and not melanin. We also used psychophysical methods to investigate the minimum color change required to confer perceptibly healthier and more attractive skin-coloration. Modest dietary changes are required to enhance apparent health (2.91 portions per day) and attractiveness (3.30 portions). Conclusions Increased fruit and vegetable consumption confers measurable and perceptibly beneficial effects on Caucasian skin appearance within six weeks. This effect could potentially be used as a motivational tool in dietary intervention.

Oxygenated-Blood Colour Change Thresholds for Perceived Facial Redness, Health, and Attractiveness

Blood oxygenation level is associated with cardiovascular fitness, and raising oxygenated blood colouration in human faces increases perceived health. The current study used a two-alternative forced choice (2AFC) psychophysics design to quantify the oxygenated blood colour (redness) change threshold required to affect perception of facial colour, health and attractiveness. Detection thresholds for colour judgments were lower than those for health and attractiveness, which did not differ. The results suggest redness preferences do not reflect a sensory bias, rather preferences may be based on accurate indications of health status. Furthermore, results suggest perceived health and attractiveness may be perceptually equivalent when they are assessed based on facial redness. Appearance-based motivation for lifestyle change can be effective; thus future studies could assess the degree to which cardiovascular fitness increases face redness and could quantify changes in aerobic exercise needed to increase facial attractiveness.

Hot or not? Thermal reactions to social contact

Previous studies using thermal imaging have suggested that face and body temperature increase during periods of sexual arousal. Additionally, facial skin temperature changes are associated with other forms of emotional arousal, including fear and stress. This study investigated whether interpersonal social contact can elicit facial temperature changes. Study 1: infrared images were taken during a standardized interaction with a same- and opposite-sex experimenter using skin contact in a number of potentially high–intimate (face and chest) and low–intimate (arm and palm) locations. Facial skin temperatures significantly increased from baseline during the face and chest contact, and these temperature shifts were larger when contact was made by an opposite-sex experimenter. Study 2: the topography of facial temperature change was investigated in five regions: forehead, periorbital, nose, mouth and cheeks. Increased temperature in the periorbital, nose and mouth regions predicted overall facial temperature shifts to social contact. Our findings demonstrate skin temperature changes are a sensitive index of arousal during interpersonal interactions.

Attractive skin coloration: harnessing sexual selection to improve diet and health.

In this paper we review the mechanisms through which carotenoid coloration could provide a sexually selected cue to condition in species with elaborate color vision. Skin carotenoid pigmentation induced by fruit and vegetable consumption may provide a similar cue to health in humans (particularly light-skinned Asians and Caucasians). Evidence demonstrates that carotenoid-based skin coloration enhances apparent health, and that dietary change can perceptibly impact skin color within weeks. We find that the skin coloration associated with increased fruit and vegetable consumption benefits apparent health to a greater extent than melanin pigmentation. We argue that the benefits to appearance may motivate individuals to improve their diet and that this line of appearance research reveals a potentially powerful strategy for motivating a healthy lifestyle.

Fruit, Vegetable and Dietary Carotenoid Intakes Explain Variation in Skin-Color in Young Caucasian Women: A Cross-Sectional Study

Fruit and vegetables contain carotenoid pigments, which accumulate in human skin, contributing to its yellowness. This effect has a beneficial impact on appearance. The aim was to evaluate associations between diet (fruit, vegetable and dietary carotenoid intakes) and skin color in young women. Ninety-one Caucasian women (Median and Interquartile Range (IQR) age 22.1 (18.1–29.1) years, BMI 22.9 (18.5–31.9) kg/m2) were recruited from the Hunter region (Australia). Fruit, vegetable and dietary carotenoid intakes were estimated by a validated food frequency questionnaire. Skin color was measured at nine body locations (sun exposed and unexposed sites) using spectrophotometry. Multiple linear regression was used to assess the relationship between fruit and vegetable intakes and skin yellowness adjusting for known confounders. Higher combined fruit and vegetable intakes (β = 0.8, p = 0.017) were associated with higher overall skin yellowness values. Higher fruit combined fruit and vegetable intakes (β = 1.0, p = 0.004) were associated with increased unexposed skin yellowness. Combined fruit and vegetables plus dietary carotenoid intakes contribute to skin yellowness in young Caucasian women. Evaluation of interventions using improvements in appearance as an incentive for increasing fruit and vegetable consumption in young women is warranted.

Appealing to Vanity: Could Potential Appearance Improvement Motivate Fruit and Vegetable Consumption?

Fruit and vegetable consumption is inadequate among adults in the United States; this contributes to preventable morbidity and mortality. More effective dietary intervention strategies are needed. Recently, interventions that advertise the consequences of behavior for appearance have been successful in modifying sun-exposure habits and tobacco use. Such an approach might also facilitate dietary improvement. Consumption of carotenoid-rich fruit and vegetables positively affects skin color, which influences perceptions of health and attractiveness, and promoting such an effect may motivate target audiences to increase consumption of this important food group. This approach represents a novel direction for the field and is potentially suitable for cost-effective, population-level dissemination through the visual media.

Cross-cultural effects of fruit and vegetable consumption on skin color.

The article reports on the impact that the consumption of fruits and vegetables containing high doses of plant pigments called carotenoids can have on skin color and the overall appearance of general health in humans. A discussion of research which was conducted to investigate whether African people and Asian people share a preference which Caucasian people have for skin which has a more yellowish tone which is associated with the consumption of fruits and vegetables that contain carotenoids is presented.

A randomized controlled trial of an appearance-based dietary intervention

OBJECTIVE Inadequate fruit and vegetable consumption precipitates preventable morbidity and mortality. The efficacy of an appearance-based dietary intervention was investigated, which illustrates the beneficial effect that fruit and vegetable consumption has on skin appearance. METHODS Participants were randomly allocated to three groups receiving information-only or a generic or own-face appearance-based intervention. Diet was recorded at baseline and 10 weekly follow-ups. Participants in the generic and own-face intervention groups witnessed on-screen stimuli and received printed photographic materials to illustrate the beneficial effect of fruit and vegetable consumption on skin color. RESULTS Controlling for baseline diet, a significant effect of intervention group was found on self-reported fruit and vegetable intake among 46 completers who were free of medical and personal reasons preventing diet change. The own-face appearance-based intervention group reported a significant, sustained improvement in fruit and vegetable consumption whereas the information-only and generic appearance-based intervention groups reported no significant dietary changes. CONCLUSIONS Seeing the potential benefits of fruit and vegetable consumption on own skin color may motivate dietary improvement.

Perceptions of carotenoid and melanin colouration in faces among young Australian adults

Objective Human skin colour is influenced by three pigments: haemoglobin, carotenoids, and melanin. Carotenoids are abundant in fruits and vegetables, and when consumed accumulate in all layers of the skin, predominantly imparting yellowness (b*). This study investigated the effect of the manipulation of carotenoid‐based skin colour, relative to the skin colour conferred by melanin on the perceptions of health amongst a group of Australian adults. Method Fifty‐seven participants (n = 4 male; mean age 27.9 ± 7.5-years) completed three computer‐based experiments on 50 trial faces. In the first two experiments, face image colour was manipulated along one or two independent single carotenoid or melanin axes on each trial to ‘make the face appear as healthy as possible’. In the third trial, face colour was manipulated on both the carotenoid and melanin axes simultaneously. Results For the single axis, participants significantly increased melanin colouration and added carotenoid colouration to facial images that were initially low in skin yellowness (b*). When carotenoid and melanin axes were simultaneously manipulated, carotenoid colouration was raised (ΔE  = 3.15 ( SE  ±0.19)) and melanin colouration was lowered (ΔE  = −1.04 ( SE  ±0.1)). Conclusions Young Australian adults perceive facial skin colouration, associated with both carotenoid intake from fruit and vegetables and melanin due to sun exposure as conveying the appearance of health in young adults. However, carotenoid colouration was more important to health perception.

Self-reported weight and predictors of missing responses in youth

OBJECTIVE The aims of the present manuscript are to analyse self-reported data on weight, including the missing data, from the 2014 Scottish Health Behaviour in School-Aged Children (HBSC) Study, and to investigate whether behavioural factors related with overweight and obesity, namely dietary habits, physical activity and sedentary behaviour, are associated with weight non-response. RESEARCH METHODS & PROCEDURES 10839 11-, 13- and 15-year-olds participated in the cross-national 2014 Scottish HBSC Study. Weight missing data was evaluated using Littles Missing Completely at Random (MCAR) test. Afterwards, a fitted multivariate logistic regression model was used to determine all possible multivariate associations between weight response and each of the behavioural factors related with obesity. RESULTS 58.9% of self-reported weight was missing, not at random (MCAR p < 0.001). Weight was self-reported less frequently by girls (19.2%) than by boys (21.9%). Participants who reported low physical activity (OR 1.2, p < 0.001), low vegetable consumption (OR 1.24, p < 0.001) and high computer gaming on weekdays (OR 1.18, p = 0.003) were more likely to not report their weight. CONCLUSIONS There are groups of young people in Scotland who are less likely to report their weight. Their weight status may be of the greatest concern because of their poorer health profile, based on key behaviours associated with their non-response. Furthermore, knowing the value of a healthy weight and reinforcing healthy lifestyle messages may help raise youth awareness of how diet, physical activity and sedentary behaviours can influence weight.