Dr Kris Pezdirc
Post Doctoral Fellow Project Manger
School of Health Sciences
- Phone:(02) 4085 4956
Dr. Pezdirc is a post-doctoral researcher at the Priority Research Centre for Physical Activity and Nutrition and the School of Health Sciences. She was awarded her PhD from the University of Newcastle in February 2016. She also completed a Bachelor of Nutrition and Dietetics (Hons I) at the University of Newcastle in 2010.
Dr Pezdirc’s research focuses on young adults , fruit and vegetable intake and carotenoids and skin colour.
- Doctor of Philosophy, University of Newcastle
- Bachelor of Nutrition and Dietetics (Honours), University of Newcastle
- fruit and vegetables
- skin colour
- young adults
- Slovene (Mother)
Fields of Research
|111199||Nutrition and Dietetics not elsewhere classified||100|
For publications that are currently unpublished or in-press, details are shown in italics.
Journal article (8 outputs)
Pezdirc K, Rollo ME, Whitehead R, Hutchesson MJ, Ozakinci G, Perrett D, Collins CE, 'Perceptions of carotenoid and melanin colouration in faces among young Australian adults', Australian Journal of Psychology, (2017)
Â© 2017 The Australian Psychological Society.Objective: Human skin colour is influenced by three pigments: haemoglobin, carotenoids, and melanin. Carotenoids are abundant in fruit... [more]
Â© 2017 The Australian Psychological Society.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 27.9Â±7.5years) 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 (Â¿E =3.15 ( SE Â±0.19)) and melanin colouration was lowered (Â¿E =-1.04 ( SE Â±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.
Pezdirc K, Hutchesson MJ, Williams RL, Rollo ME, Burrows TL, Wood LG, et al., 'Consuming High-Carotenoid Fruit and Vegetables Influences Skin Yellowness and Plasma Carotenoids in Young Women: A Single-Blind Randomized Crossover Trial', Journal of the Academy of Nutrition and Dietetics, 116 1257-1265 (2016) [C1]
Â© 2016 Academy of Nutrition and DieteticsBackground Consumption of dietary carotenoids from fruits and vegetables (F/V) leads to accumulations in human skin, altering skin yellow... [more]
Â© 2016 Academy of Nutrition and DieteticsBackground Consumption of dietary carotenoids from fruits and vegetables (F/V) leads to accumulations in human skin, altering skin yellowness. The influence of the quantity of F/V consumed on skin yellowness and plasma carotenoid concentrations has not been examined previously. Objective To compare the influence of consuming high-carotenoid-containing F/V (HCFV) (176,425 Âµg beta carotene/wk) vs low-carotenoid F/V (LCFV) (2,073 Âµg beta carotene/wk) on skin yellowness and plasma carotenoid concentrations, over 4 weeks. Design and intervention A single-blind randomized controlled crossover trial from October 2013 to March 2014. Thirty women were randomized to receive 7 daily servings of HCFV or LCFV for 4 weeks. Following a 2-week washout period they followed the alternate intervention. Main outcome measures Skin color (Commission Internationale de l'Eclairage L*a*b* color space, where L* represents skin lightness and positive values of a* and b* represent degrees of redness and yellowness, respectively) was assessed by reflectance spectroscopy in both sun-exposed and nonexposed skin areas. Fasting plasma carotenoids were determined by high-performance liquid chromatography, before and after each intervention period. Statistical analyses performed Linear mixed models were used to determine the HCFV and LCFV response on skin color and plasma carotenoids, adjusting for intervention order, time, and interaction between baseline differences and time. Results There were no significant differences in mean daily fruit (P=0.42) and vegetable (P=0.17) intakes between HCFV and LCFV groups. Dietary alpha carotene, beta carotene, lutein, and beta cryptoxanthin intakes were significantly different between the two groups (P<0.01). Following HCFV there was a significantly greater increase in skin yellowness (b*) in both sun-exposed (P<0.001) and unexposed areas, (P<0.001), with no change in skin lightness (L*) or redness (a*). Significantly higher plasma alpha carotene (P=0.004), beta carotene (P=0.001), and lutein (P=0.028) concentrations were found following the HCFV intervention. Skin yellowness correlated with alpha carotene and beta carotene. Conclusions Skin yellowness (b*) and fasting plasma carotenoid concentrations were significantly higher following HCFV than LCFV over 4 weeks.
Collins CE, Bucher T, Taylor A, Pezdirc K, Lucas H, Watson J, et al., 'How big is a food portion? A pilot study in Australian families', Health Promotion Journal of Australia, 26 83-88 (2015) [C1]
Â© 2015 Australian Health Promotion Association.Issues addressed It is not known whether individuals can accurately estimate the portion size of foods usually consumed relative to... [more]
Â© 2015 Australian Health Promotion Association.Issues addressed It is not known whether individuals can accurately estimate the portion size of foods usually consumed relative to standard serving sizes in national food selection guides. The aim of the present cross-sectional pilot study was to quantify what adults and children deem a typical portion for a variety of foods and compare these with the serving sizes specified in the Australian Guide to Healthy Eating (AGHE). Methods Adults and children were independently asked to serve out their typical portion of 10 common foods (rice, pasta, breakfast cereal, chocolate, confectionary, ice cream, meat, vegetables, soft drink and milk). They were also asked to serve what they perceived a small, medium and large portion of each food to be. Each portion was weighed and recorded by an assessor and compared with the standard AGHE serving sizes. Results Twenty-one individuals (nine mothers, one father, 11 children) participated in the study. There was a large degree of variability in portion sizes measured out by both parents and children, with means exceeding the standard AGHE serving size for all items, except for soft drink and milk, where mean portion sizes were less than the AGHE serving size. The greatest mean overestimations were for pasta (155%; mean 116 g; range 94-139g) and chocolate (151%; mean 38 g; range 25-50g), each of which represented approximately 1.5 standard AGHE servings. Conclusion The findings of the present study indicate that there is variability between parents' and children's estimation of typical portion sizes compared with national recommendations. So what? Dietary interventions to improve individuals' dietary patterns should target education regarding portion size.
Collins CE, Burrows TL, Rollo ME, Boggess MM, Watson JF, Guest M, et al., 'The comparative validity and reproducibility of a diet quality index for adults: The Australian recommended food score', Nutrients, 7 785-798 (2015) [C1]
Pezdirc K, Hutchesson MJ, Whitehead R, Ozakinci G, Perrett D, Collins CE, 'Fruit, vegetable and dietary carotenoid intakes explain variation in skin-color in young Caucasian women: A cross-sectional study', Nutrients, 7 5800-5815 (2015) [C1]
Â© 2015 by the authors; licensee MDPI, Basel, Switzerland.Fruit and vegetables contain carotenoid pigments, which accumulate in human skin, contributing to its yellowness. This ef... [more]
Â© 2015 by the authors; licensee MDPI, Basel, Switzerland.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 (18.1Â¿29.1) years, BMI 22.9 (18.5Â¿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 (Ã = 0.8, p = 0.017) were associated with higher overall skin yellowness values. Higher fruit combined fruit and vegetable intakes (Ã = 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.
Pezdirc K, Hutchesson M, Whitehead R, Ozakinci G, Perrett D, Collins CE, 'Can dietary intake influence perception of and measured appearance? A Systematic Review', Nutrition Research, 35 175-197 (2015) [C1]
Â© 2015 Elsevier Inc.Appearance-based interventions have had some success in reducing smoking and sun exposure. Appearance may also motivate dietary behavior change if it was esta... [more]
Â© 2015 Elsevier Inc.Appearance-based interventions have had some success in reducing smoking and sun exposure. Appearance may also motivate dietary behavior change if it was established that dietary improvement had a positive impact on appearance. The aims of this review are to evaluate the current evidence examining the relationship between dietary intake and appearance and to determine the effectiveness of dietary interventions on perceived or actual appearance. An electronic search of English-language studies up to August 2012 was conducted using Cochrane, MEDLINE, Embase, CINAHL, Web of Science, SCOPUS, and PsycINFO databases. Studies that included participants aged at least 18 years, that observed or altered dietary intake from actual food or dietary supplement use, and assessed appearance-related outcomes were considered eligible. Data from 27 studies were extracted and assessed for quality using standardized tools. Nineteen studies were assessed as being of "positive" and 4 of "neutral" quality. All observational studies (n = 4741 participants) indicated that there was a significant association between various aspects of dietary intake and skin coloration and skin aging. The majority (16 studies, 769 participants) evaluated the effect of dietary supplements on skin appearance among women. Only 1 study examined the effect of actual food intake on appearance. Significant improvements in at least 1 actual or perceived appearance-related outcome (facial wrinkling, skin elasticity, roughness, and skin color) following dietary intervention were shown as a result of supplementation. Further studies are needed in representative populations that examine actual food intake on appearance, using validated tools in well-designed high-quality randomized control trials.
Collins CE, Boggess MM, Watson JF, Guest M, Duncanson K, Pezdirc K, et al., 'Reproducibility and comparative validity of a food frequency questionnaire for Australian adults', Clinical Nutrition, 33 906-914 (2014) [C1]
Background: Food frequency questionnaires (FFQ) are used in epidemiological studies to investigate the relationship between diet and disease. There is a need for a valid and relia... [more]
Background: Food frequency questionnaires (FFQ) are used in epidemiological studies to investigate the relationship between diet and disease. There is a need for a valid and reliable adult FFQ with a contemporary food list in Australia. Aims: To evaluate the reproducibility and comparative validity of the Australian Eating Survey (AES) FFQ in adults compared to weighed food records (WFRs). Methods: Two rounds of AES and three-day WFRs were conducted in 97 adults (31 males, median age and BMI for males of 44.9 years, 26.2 kg/m2, females 41.3 years, 24.0 kg/m2. Reproducibility was assessed over six months using Wilcoxon signed-rank tests and comparative validity was assessed by intraclass correlation coefficients (ICC) estimated by fitting a mixed effects model for each nutrient to account for age, sex and BMI to allow estimation of between and within person variance. Results: Reproducibility was found to be good for both WFR and FFQ since there were no significant differences between round 1 and 2 administrations. For comparative validity, FFQ ICCs were at least as large as those for WFR. The ICC of the WFR-FFQ difference for total energy intake was 0.6 (95% CI 0.43, 0.77) and the median ICC for all nutrients was 0.47, with all ICCs between 0.15 (%E from saturated fat) and 0.7 (g/day sugars). Conclusions: Compared to WFR the AES FFQ is suitable for reliably estimating the dietary intakes of Australian adults across a wide range of nutrients. Â© 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism.
Pezdirc KB, Hure AJ, Blumfield ML, Collins CE, 'Listeria monocytogenes and diet during pregnancy; balancing nutrient intake adequacy v. adverse pregnancy outcomes', Public Health Nutrition, 15 2202-2209 (2012) [C1]
|Show 5 more journal articles|
Conference (7 outputs)
|2016||Pezdirc KB, 'Can dietary intake influence perception of and measured appearance? A systematic Review.', ) Can dietary intake influence perception of and measured appearance? A systematic Review. (2016)|
Rollo M, Whitehead R, Pezdirc K, Hutchesson M, Ozakinci G, Perrett D, Collins CE, 'Perceptions of a healthy appearance: Insights for behavioural interventions targeting fruit and vegetable intake', https://www.isbnpa.org/index.php?r=annualMeeting/index&year=2014 (2014)
Pezdirc K, Hutchesson MJ, Collins CE, 'Impact of high versus low carotenoid fruit and vegetables on skin colour and plasma carotenoids in young women' (2014)
Pezdirc K, Hutchesson M, Collins CE, Whitehead R, Perrett D, Ozakinci G, 'Does dietary intake influence self-perception of and actual appearance? A systematic review', Australasian Medical Journal (2013) [E3]
Pezdirc K, Hutchesson M, Collins CE, 'Fruit and vegetable intakes, BMI and skin colour in women: A cross-sectional study', Obesity Research and Clinical Practice (2013) [E3]
Pezdirc KB, Collins CE, Watson JF, Burrows TL, Guest M, Boggess M, Duncanson KR, 'Validation of an adult food frequency questionnaire', Nutrition & Dietetics: Special Issue: Dietitians Association of Australia 16th International Congress of Dietetics (2012) [E3]
|Show 4 more conferences|
Grants and Funding
|Number of grants||3|
Click on a grant title below to expand the full details for that specific grant.
20161 grants / $21,000
Funding body: Quality Bakers Australia Pty Limited
|Funding body||Quality Bakers Australia Pty Limited|
|Project Team||Professor Clare Collins, Doctor Megan Rollo, Associate Professor Tracy Burrows, Doctor Tamara Bucher, Doctor Kris Pezdirc, Miss Rebecca Williams|
|Type Of Funding||Grant - Aust Non Government|
20122 grants / $34,519
Funding body: HMRI
|Scheme||Thomson Family Top Up Scholarship|
|Type Of Funding||Not Known|
Funding body: PRC in Physical Activity and Nutrition, University of Newcastle
|Funding body||PRC in Physical Activity and Nutrition, University of Newcastle|
|Scheme||Priority Research Council (PRC) in Physical Activity and Nutrition Seed Grant Funding|
|Type Of Funding||Internal|
The map is a representation of a researchers co-authorship with collaborators across the globe. The map displays the number of publications against a country, where there is at least one co-author based in that country. Data is sourced from the University of Newcastle research publication management system (NURO) and may not fully represent the authors complete body of work.
|Country||Count of Publications|
May 19, 2017
New research from the University of Newcastle (UON) has busted the myth that young adults perceive tanned facial skin to be healthy and attractive.
October 16, 2013
Can increasing your fruit and vegetable intake improve your skin colour and appearance? A University of Newcastle study is searching for the answer with the hope it could be a powerful motivator to encourage people to eat healthier.