Katharina Wirnitzer

Dr. Katharina Wirnitzer

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
6 April 2021 in Nutrients
Verified
Journal Article
Open access
PDF file
Mohamad MotevalliMohamad Motevalli
Mohamad Motevalli
Clemens DrenowatzClemens Drenowatz
Clemens Drenowatz
DTDerrick R. Tanous
Derrick R. Tanous
Naim KhanNaim Khan
Naim Khan
KWKatharina Wirnitzer
Katharina Wirnitzer
As a major public health concern, childhood obesity is a multifaceted and multilevel metabolic disorder influenced by genetic and behavioral aspects. While genetic risk factors contribute to and interact with the onset and development of excess body weight, available evidence indicates that several modifiable obesogenic behaviors play a crucial role in the etiology of childhood obesity. Although a variety of systematic reviews and meta-analyses have reported the effectiveness of several interventions in community-based, school-based, and home-based programs regarding childhood obesity, the prevalence of children with excess body weight remains high. Additionally, researchers and pediatric clinicians are often encountering several challenges and the characteristics of an optimal weight management strategy remain controversial. Strategies involving a combination of physical activity, nutritional, and educational interventions are likely to yield better outcomes compared to single-component strategies but various prohibitory limitations have been reported in practice. This review seeks to (i) provide a brief overview of the current preventative and therapeutic approaches towards childhood obesity, (ii) discuss the complexity and limitations of research in the childhood obesity area, and (iii) suggest an Etiology-Based Personalized Intervention Strategy Targeting Childhood Obesity (EPISTCO). This purposeful approach includes prioritized nutritional, educational, behavioral, and physical activity intervention strategies directly based on the etiology of obesity and interpretation of individual characteristics.

PBPatrick Boldt
Patrick Boldt
Beat KnechtleBeat Knechtle
Beat Knechtle
Pantelis T. NikolaidisPantelis T. Nikolaidis
Pantelis T. Nikolaidis
CLChristoph Lechleitner
Christoph Lechleitner
GWGerold Wirnitzer
Gerold Wirnitzer
KWKatharina Wirnitzer
Katharina Wirnitzer
Health-related effects of a vegetarian or vegan diet are known to support parameters positively affecting exercise performance in athletes, whereas knowledge about psyche and wellbeing is sparse. Therefore, the aim of the Nutrition and Running High Mileage (NURMI) Study (Step 2) was to compare Quality of Life (QOL) scores among endurance runners following a vegetarian or vegan diet against those who adhere to an omnivorous diet. The study was conducted following a cross-sectional design. A total of 281 recreational runners (159 women, 122 men) completed the WHOQOL-BREF questionnaire consisting of the domains physical health, psychological wellbeing, social relationships and environment, which generates scores on a scale from 4 to 20. Data analysis was performed using ANOVA. It was found that 123 subjects followed an omnivorous diet and 158 adhered to a vegetarian/vegan diet. There were 173 runners who met the inclusion criteria (‘NURMI-Runners’), among them 103 half-marathoners and 70 marathoners and ultramarathoners, as well as 108 10 km runners as control group. Overall QOL scores were high (~ 16.62 ± 1.91). Men had higher scores than women due to high scores in the physical health and psychological well-being dimensions. Adhering to an omnivorous diet affected environment scores for women and social relationships scores for men. A minor effect concerning race distance was observed in women, where half-marathoners had a higher environmental score than 10-km runners. A moderate diet×race distance interaction on environment scores was shown for men. The results revealed that endurance runners had a high QOL regardless of the race distance or diet choice. These findings support the notion that adhering to a vegetarian or vegan diet can be an appropriate and equal alternative to an omnivorous diet. ISRCTN73074080 . Registered 12th June 2015, retrospectively registered.

10 August 2021 in Nutrients
Verified
Journal Article
Open access
PDF file
KWKatharina Wirnitzer
Katharina Wirnitzer
Mohamad MotevalliMohamad Motevalli
Mohamad Motevalli
DTDerrick R. Tanous
Derrick R. Tanous
MGMartina Gregori
Martina Gregori
GWGerold Wirnitzer
Gerold Wirnitzer
Beat KnechtleBeat Knechtle
Beat Knechtle
Nutrient deficiency is a common cause of underperformance in endurance athletes, and supplement intake is frequently considered compensatory for vegan and vegetarian athletes specifically. This study aimed to investigate the patterns of supplement intake among vegan, vegetarian, and omnivorous distance (>10 km) runners and its association with age, sex, and race distance. From a total of 317 runners who participated in an online survey, 220 distance runners (mean age: 38.5 years; mean BMI: 21.75 kg/m2) were selected for the final sample after data clearance and assigned to 100 omnivores, 40 vegetarians, or 80 vegans. Sociodemographic information, racing experience, and patterns of supplement intake, including type, frequency, dosage, etc., were collected using a questionnaire. Macronutrient intake was assessed using a food frequency questionnaire. ANOVA and logistic regression were used for data analysis. The prevalence of supplement intake was 51% for total runners and 72% among vegan runners. Age, sex, and race distance had no significant effect on the type of supplement intake (p > 0.05). Compared to omnivores and vegetarians, vegan runners reported consuming more vitamin (but not carbohydrate/protein or mineral) supplements (p < 0.05). Vitamin B12, magnesium, and multivitamin had the most prevalent use amongst micronutrient supplements. This study points to a central role for supplementary nutritional strategies in different groups of distance runners. The present findings may help future investigations by design to identify specific requirements of endurance runners when adhering to specific kinds of diet particularly plant-based diets.

KWKatharina Wirnitzer
Katharina Wirnitzer
Clemens DrenowatzClemens Drenowatz
Clemens Drenowatz
Armando CoccaArmando Cocca
Armando Cocca
DTDerrick R. Tanous
Derrick R. Tanous
Mohamad MotevalliMohamad Motevalli
Mohamad Motevalli
WKWerner Kirschner
Werner Kirschner
Attaining healthy behaviors is essential at any life stage, particularly childhood, due to the strong link between children’s lifestyle and the subsequent adult state of health. This multidisciplinary study aimed to assess lifestyle behaviors of Austrian pupils of secondary schools I and II, with a specific focus on PA habits and diet types based on a large sample. In total, 8845 children/adolescents participated in the short standardized online survey on relevant health-related aspects nationwide. Valid and complete data was provided by 8799 pupils, including 1.14% of the eligible 771,525; 63% girls, 76% having a normal body weight, 70% attending secondary schools II, and more pupils/students living in rural vs. urban areas (3:1 ratio). Across the total sample, 11.8% were considered overweight/obese with a higher prevalence of overweight/obesity in boys than girls (15.5% vs. 9.6%) and urban vs. rural participants (13.9% vs. 10.8%; p < 0.05). The majority of participants (84.5%) reported a mixed diet, while 7.2% and 8.5% reported a vegan and vegetarian diet, respectively. Vegans reported a lesser alcohol intake (p < 0.05) compared to non-vegan pupils (no difference in dietary subgroups for smoking). Although overall PA and dietary behaviors suggest an appropriate health status among Austrian youth, attention should be focused on policies to increase healthy lifestyle habits at best through a dual approach to health permanently combining regular PA, sports, and exercise with a healthy diet, which would contribute to matching the current recommendations for improving individual and public health.

13 August 2021 in Nutrients
Verified
Journal Article
Open access
PDF file
KWKatharina Wirnitzer
Katharina Wirnitzer
Mohamad MotevalliMohamad Motevalli
Mohamad Motevalli
DTDerrick R. Tanous
Derrick R. Tanous
MGMartina Gregori
Martina Gregori
GWGerold Wirnitzer
Gerold Wirnitzer
Beat KnechtleBeat Knechtle
Beat Knechtle
It has been well-documented that female and male athletes differ in many physiological and psychological characteristics related to endurance performance. This sex-based difference appears to be associated with their nutritional demands including the patterns of supplement intake. However, there is a paucity of research addressing the sex differences in supplement intake amongst distance runners. The present study aimed to investigate and compare supplement intake between female and male distance runners (10 km, half-marathon, (ultra-)marathon) and the potential associations with diet type and race distance. A total of 317 runners participated in an online survey, and 220 distance runners (127 females and 93 males) made up the final sample after a multi-stage data clearance. Participants were also assigned to dietary (omnivorous, vegetarian, vegan) and race distance (10-km, half-marathon, marathon/ultra-marathon) subgroups. Sociodemographic characteristics and the patterns of supplement intake including type, frequency, dosage, and brands were collected using a questionnaire. One-way ANOVA and logistic regression were used for data analysis. A total of 54.3% of female runners and 47.3% male runners reported consuming supplements regularly. The frequency of supplement intake was similar between females and males (generally or across dietary and distance subgroups). There was no significant relationship for sex alone or sex interactions with diet type and race distance on supplement intake (p < 0.05). However, a non-significant higher intake of vitamin and mineral (but not CHO/protein) supplements was reported by vegan and vegetarian (but not by omnivorous) females compared to their male counterparts. In summary, despite the reported findings, sex could not be considered as a strong modulator of supplement intake among different groups of endurance runners.

1 July 2019 in Journal of Strength & Conditioning Research
Verified
Journal Article
Closed access
PBPatrick Boldt
Patrick Boldt
BKBeat Knechtle
Beat Knechtle
Pantelis T. NikolaidisPantelis T. Nikolaidis
Pantelis T. Nikolaidis
CLChristoph Lechleitner
Christoph Lechleitner
GWGerold Wirnitzer
Gerold Wirnitzer
KWKatharina Wirnitzer
Katharina Wirnitzer
Boldt, P, Knechtle, B, Nikolaidis, P, Lechleitner, C, Wirnitzer, G, Leitzmann, C, and Wirnitzer, K. Sex differences in the health status of endurance runners: results from the NURMI study (step 2). J Strength Cond Res 33(7): 1929–1940, 2019—Optimized endurance performance is closely linked to a good health status (HS), which is crucially affected by sex. Therefore, the purpose of this study was to investigate sex differences in the HS of endurance runners of different distances. A total of 281 female and male recreational runners completed an online survey. Health status included body mass, smoking habits, felt stress, chronic diseases, allergies, intolerances, medication intake, supplement intake, health-related food choice, enhancement substance use, and health care utilization. Data analysis was performed using the independent t-test and chi-squared test with Cohen's d and Cramer's phi (φ) to evaluate the magnitude of the differences and associations. There were 159 female and 122 male participants, with 173 runners meeting the inclusion criteria, among them 103 half-marathoners, and 70 marathoners and ultramarathoners, of which one hundred eight 10-km runners were defined as the control group. Statistical significance (p < 0.05) was determined for the following findings: there was a higher prevalence of hypothyroidism in women; the use of thyroid medication and the intake of hormones and supplements prescribed by a doctor were more common in women; men reported more often a decrease in body mass due to running training, and women reported more often choosing food to obtain phytochemicals. There was no statistically significant association (p > 0.05) between sex and body mass change because of a change in diet, smoking habits, felt stress, chronic diseases except hypothyroidism, allergies, food intolerances, intake of antihypertensives and cholesterol-lowering medication, intake of performance-enhancing substances, or health care utilization. Both female and male runners had a good HS with no difference between sexes. Based on the findings of this study, monitoring thyroid parameters and vitamin D levels is required in female athletes, whereas adequate body mass control strategies are needed for their male counterparts.