| 1. |
- Virtanen, Marianna, et al.
(författare)
-
Long working hours and change in body weight : analysis of individual-participant data from 19 cohort studies
- 2020
-
Ingår i: International Journal of Obesity. - : Nature Publishing Group. - 0307-0565 .- 1476-5497. ; 44:6, s. 1368-1375
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the relation between long working hours and change in body mass index (BMI). Methods: We performed random effects meta-analyses using individual-participant data from 19 cohort studies from Europe, US and Australia (n = 122,078), with a mean of 4.4-year follow-up. Working hours were measured at baseline and categorised as part time (<35 h/week), standard weekly hours (35–40 h, reference), 41–48 h, 49–54 h and ≥55 h/week (long working hours). There were four outcomes at follow-up: (1) overweight/obesity (BMI ≥ 25 kg/m2) or (2) overweight (BMI 25–29.9 kg/m2) among participants without overweight/obesity at baseline; (3) obesity (BMI ≥ 30 kg/m2) among participants with overweight at baseline, and (4) weight loss among participants with obesity at baseline. Results: Of the 61,143 participants without overweight/obesity at baseline, 20.2% had overweight/obesity at follow-up. Compared with standard weekly working hours, the age-, sex- and socioeconomic status-adjusted relative risk (RR) of overweight/obesity was 0.95 (95% CI 0.90–1.00) for part-time work, 1.07 (1.02–1.12) for 41–48 weekly working hours, 1.09 (1.03–1.16) for 49–54 h and 1.17 (1.08–1.27) for long working hours (P for trend <0.0001). The findings were similar after multivariable adjustment and in subgroup analyses. Long working hours were associated with an excess risk of shift from normal weight to overweight rather than from overweight to obesity. Long working hours were not associated with weight loss among participants with obesity. Conclusions: This analysis of large individual-participant data suggests a small excess risk of overweight among the healthy-weight people who work long hours.
|
|
| 2. |
- Azzinnari, M, et al.
(författare)
-
Efectos del ejercicio en la señalización de NF-kB durante la restricción calórica severa
- 2017
-
Konferensbidrag (refereegranskat)abstract
- El sobrepeso y la obesidad, en crecimiento en todo el mundo, se asocian con una alta tasa de mortalidad e morbilidad[1,2]. La causa principal que conduce a éstas condiciones patológicas es un balance energético positivo sostenido a largo plazo, debido a la inactividad física y la ingesta calórica excesiva[3]. Por lo tanto, ejercicio físico y restricción calórica podrían ser dos estratégias eficaces para prevenir y contrastar el excesivo acumulo de grasa corporal que caracteriza estas patologías. Sin embargo, durante dietas muy bajas en calorías (<800 Kcal/día) se pierde no solo masa grasa sino también masa muscular, reportando efectos negativos para la salud[4]. En dichas condiciones, el ejercicio físico permite preservar masa muscular de manera local y dosis-dependiente, mientras la ingestión de proteínas no ejerce particulares efectos protectivos sobre el tejido contráctil[5]. Los mecanismos moleculares implicados en la preservación de la masa muscular inducida por el ejercicio durante este tipo de dietas no han sido definidos claramente. NF-kB es un factor de transcripción cuya activación provoca atrofia muscular, y su bloqueo puede parcialmente limitar este fenomeno[6]. NF-kB se ha mostrado activado de manera aguda por el ejercicio y la restricción calorica, sin embargo no ha sido definida su respuesta a la restricción calórica en conjunción con el ejercicio prolongado de baja intensidad. Además, cuando los niveles basales de NF-kB son altos, el ejercicio no parece aumentar ulteriormente su señalización[7]. Por las razones presentadas, NF-kB podría desempeñar un rol en la preservación de masa magra inducida por el ejercicio durante la restricción calórica.El objetivo del estudio es establecer la respuesta de NF-kB a la restricción calórica severa en conjunción con el ejercicio prolongado de baja intensidad. Las hipótesis fueron las siguientes: 1) la restricción calórica severa activaría la via de NF-kB y 2) dicha activación será atenuada por el ejercicio de manera local y dosis-dependiente.15 sujetos con sobrepeso y obesidad fueron sometidos a tres fases experimentales: fase 1, en la que la dieta y el nivel de actividad física de los participantes fue monitorizado durante una semana (PRE); fase 2, caracterizada por cuatro días de ejercicio prolongado y de restricción calórica severa (RCE); fase 3, caracterizada por tres días de ejercicio reducido y una dieta isoenergética (DC). Durante la fase 2, los sujetos ingeriron hidratos de carbono o proteínas (0.8 g/kg peso corporal/día; 320 kcal/día) y hicieron 45 minutos de pedaleo con un solo miembro superior (15% Ppeak) seguidos de 8 horas de caminata (4.5 km/h; 35 km/día). Las biopsias musculares fueron recogidas de ambos los deltoides y del vasto lateral en la fase 1 y después de la fase 2 y 3. Mediante Western blot, se determinó la expresión de NF-κB p105, NF-κB p50, la fosforilación de la Serina 32/36 de IκBα e IκBα total. La composición corporal se midió mediante DXA. Estadística: ANOVA para medidas repetidas.Durante los 4 días de restricción calórica severa el deficit energético fue de 5500 Kcal. Después de la fase 2 los sujetos perdieron menos masa magra en los miembros inferiores y en el brazo ejercitado respecto al brazo de control: 57% (P<0.05) y 29% (P=0.05), respectivamente. Tras la fase 2 y 3, el contenido de p105 y de p50 fue menor en los miembros inferiores respecto a los superiores: efecto extremidad P=0.003 y P=0.024 para p105 y p50, respectivamente. Tras la fase 3, la fosforilación de la Serina 32/36 de IkBα aumentó únicamente en las piernas, mientras la expresión total IkBα fue mayor solo en los miembros ejercitados (P<0.05).El ejercicio físico atenuó la activación de la señalización de NF-kB durante 4 días de restricción calórica severa, limitando el incremento de la expresión de p50 y p105, que resultó más baja después de la fase 2 y la fase 3 en los miembros inferiores respecto a los miembros superiores, posiblemente debido a la mayor cantidad de ejercicio a la que fueron sometidos. Además, la expresión total de IkBα fue más alta tras la fase 3 solo en los miembros ejercitados, indicando una posible inhibición de la vía de NF-kB inducida por el ejercicio. Por lo tanto, dado la menor activación de la señalización de NF-kB en los miembros que perdieron menor masa muscular, los resultados sugieren que los efectos protectores del ejercicio físico sobre el tejido contráctil podrían ser mediados a una menor activación de la señalización de NF-kB.El ejercicio físico desempeña una función preservadora sobre la masa muscular durante la restricción calórica severa. La preservación de masa muscular es dosis-dependiente (a mayor volumen, mayor preservación) y está mediada, al menos parcialmente, por una menor activación de la señalización por NF-kB.1.Hill, J. O., H. R. Wyatt, et al. (2012). Circulation 126(1): 126-132.2.Di Angelantonio, E., N. Bhupathiraju Sh, et al. (2016). Lancet 388(10046): 776-786. 3.Chaston, T. B., J. B. Dixon, et al. (2007). Int J Obes (Lond) 31(5): 743-750. 4.Calbet, J. A., J. G. Ponce-Gonzalez, et al. (2017). Front Physiol (Accepted, In press).5.Cai, D., J. D. Frantz, et al. (2004). Cell 119(2): 285-298.6.Tantiwong, P., K. Shanmugasundaram, et al. (2010). Am J Physiol Endocrinol Metab 299(5): E794-801.7.NCD-RisC (2016). Lancet 387(10026): 1377-1396.
|
|
| 3. |
- Carr, Amelia, et al.
(författare)
-
Nutritional Intake in Elite Cross-Country Skiers During Two Days of Training and Competition
- 2019
-
Ingår i: International Journal of Sport Nutrition & Exercise Metabolism. - Birmingham : Human Kinetics. - 1526-484X .- 1543-2742. ; 29:3, s. 273-281
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the energy, macronutrient, and fluid intakes, as well as hydration status (urine specific gravity), in elite cross-country skiers during a typical day of training (Day 1) and a sprint skiing competition the following day (Day 2). A total of 31 (18 males and 13 females) national team skiers recorded their food and fluid intakes and urine specific gravity was measured on Days 1 and 2. In addition, the females completed the Low Energy Availability in Females Questionnaire to assess their risk of long-term energy deficiency. Energy intake for males was 65 ± 9 kcal/kg on Day 1 versus 58 ± 9 kcal/kg on Day 2 (p = .002) and for females was 57 ± 10 on Day 1 versus 55 ± 5 kcal/kg on Day 2 (p = .445). Carbohydrate intake recommendations of 10-12 g·kg-1·day-1 were not met by 89% of males and 92% of females. All males and females had a protein intake above the recommended 1.2-2.0 g/kg on both days and a postexercise protein intake above the recommended 0.3 g/kg. Of the females, 31% were classified as being at risk of long-term energy deficiency. In the morning of Day 1, 50% of males and 46% of females were dehydrated; on Day 2, this was the case for 56% of males and 38% of females. In conclusion, these data suggest that elite cross-country skiers ingested more protein and less carbohydrate than recommended and one third of the females were considered at risk of long-term energy deficiency. Furthermore, many of the athletes were dehydrated prior to training and competition.
|
|
| 4. |
- Nejabati, H. R., et al.
(författare)
-
N1-Methylnicotinamide : Is it Time to Consider it as a Dietary Supplement for Athletes?
- 2022
-
Ingår i: Current pharmaceutical design. - : Bentham Science Publishers Ltd.. - 1381-6128 .- 1873-4286. ; 28:10, s. 800-805
-
Forskningsöversikt (refereegranskat)abstract
- Exercise is considered to be a “medicine” due to its modulatory roles in metabolic disorders, such as diabetes and obesity. The intensity and duration of exercise determine the mechanism of energy production by various tissues of the body, especially by muscles, in which the requirement for adenosine triphosphate (ATP) increases by as much as 100-fold. Naturally, athletes try to improve their exercise performance by dietary supplementation with, e.g., vitamins, metabolites, and amino acids. MNAM, as a vitamin B3 metabolite, reduc-es serum levels and liver contents of triglycerides and cholesterol, and induces lipolysis. It stimulates gluconeo-genesis and prohibits liver cholesterol and fatty acid synthesis through the expression of sirtuin1 (SIRT1). It seems that MNAM is not responsible for the actions of NNMT in the adipose tissues as MNAM inhibits the activity of NNMT in the adipose tissue and acts as an inhibitor of its activity. NNMT-MNAM axis is more activated in the muscles of individuals undergoing the high-volume-low-intensity exercise and caloric restriction. Therefore, MNAM could be an important myokine during exercise and fasting where it provides the required energy for muscles through the induction of lipolysis and gluconeogenesis in the liver and adipose tissues, respectively. Increased levels of MNAM in exercise and fasting led us to propose that the consumption of MNAM during training, especially endurance training, could boost exercise capacity and improve perfor-mance. Therefore, in this review, we shed light on the potential of MNAM as a dietary supplement in sports medicine.
|
|
| 5. |
- PÉREZ-SUÁREZ, I, et al.
(författare)
-
LEPTIN RECEPTOR MOLECULAR VARIANTS ARE DIFFERENTLY REGULATED BY EXERCISE AND ENERGY DEFICIT IN HUMAN SKELETAL MUSCLE
- 2014
-
Konferensbidrag (refereegranskat)abstract
- IntroductionLeptin signals in skeletal muscles through pathways which share some steps with the insulin and IGF1. We have recently shown that LEPR (OBR-170) is increased in the dominant arm of tennis players 1 and is reduced in deltoid and vastus lateralis (VL) of obese compared to control subjects 2. The aim of this study was to determine whether exercise up-regulates the protein abundance and phosphorylation status of the different molecular variations of the LEPR (OBR-170, 128, 98A or 98B) in human skeletal muscle. We hypothesized that exercise will up-regulate leptin signaling in skeletal muscle. MethodsFifteen overweight men underwent three experimental phases: pre-test (PRE); caloric restriction (3.2 Kcal/kg body Wt/d) + exercise (45min unilateral arm cranking/d + 8h walking/d) for 4 days (CRE); and control isoenergetic diet + reduced exercise for 3 days (CD). During CRE, the diet consisted solely of whey protein (PRO, n=8) or sucrose (SU, n=7) (0.8 g/kg body Wt/d). Muscle biopsies (135 biopsies in all) were obtained from the trained and untrained deltoid, and VL, after 12h fast at PRE, and end of CRE and CD. The molecular variants of LEPR (OBR-170, 128, 98A and 98B) were determined by western blot and LEPR mRNA by PCR. ResultsSerum leptin was reduced by ~60% following CRE and CD (P<0.05). LEPRs were more abundant in arm than leg muscles. LEPR mRNA was increased in exercised muscles after CRE. OBR-170 was reduced after CRE and CD only in the control arm (P<0.05). OBR-128 was increased after CD in exercised extremities (P<0.05). OBR-98A was increased after CRE in trained arm, and after CD in legs (P<0.05). However, OBR-98B was increased after CRE and CD in both arms and exercised extremities (P<0.05), being these effects more pronounced in the PRO group (P<0.05). After CD, LEPR mRNA returned to basal levels while LEPR expression was increased in all muscles (P<0.05). The fraction of LEPR activated (Tyr1141 phosphorylated) was reduced in arms but not in leg muscles. LEPR phosphorylation was correlated with JAK2 (upstream) and STAT3 (downstream) phosphorylation (r=0.67-0.89, P<0.05). DiscussionCaloric restriction seems to reduce the abundance of LEPR, but this effect varies depending on specific molecular variants of the receptor. The reduction of LEPR is partly counteracted by exercise, likely contributing to increase muscle leptin sensitivity. Whey protein ingestion facilitates these effects. Resuming normal food ingestion after a period of severe energy deficit is accompanied by increased expression LEPR in skeletal muscle.
|
|
| 6. |
- Shannon, Oliver M, et al.
(författare)
-
Dietary Inorganic Nitrate as an Ergogenic Aid : An Expert Consensus Derived via the Modified Delphi Technique.
- 2022
-
Ingår i: Sports Medicine. - : Springer. - 0112-1642 .- 1179-2035. ; 52:10, s. 2537-2558
-
Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Dietary inorganic nitrate is a popular nutritional supplement, which increases nitric oxide bioavailability and may improve exercise performance. Despite over a decade of research into the effects of dietary nitrate supplementation during exercise there is currently no expert consensus on how, when and for whom this compound could be recommended as an ergogenic aid. Moreover, there is no consensus on the safe administration of dietary nitrate as an ergogenic aid. This study aimed to address these research gaps.METHODS: The modified Delphi technique was used to establish the views of 12 expert panel members on the use of dietary nitrate as an ergogenic aid. Over three iterative rounds (two via questionnaire and one via videoconferencing), the expert panel members voted on 222 statements relating to dietary nitrate as an ergogenic aid. Consensus was reached when > 80% of the panel provided the same answer (i.e. yes or no). Statements for which > 80% of the panel cast a vote of insufficient evidence were categorised as such and removed from further voting. These statements were subsequently used to identify directions for future research.RESULTS: The 12 panel members contributed to voting in all three rounds. A total of 39 statements (17.6%) reached consensus across the three rounds (20 yes, 19 no). In round one, 21 statements reached consensus (11 yes, 10 no). In round two, seven further statements reached consensus (4 yes, 3 no). In round three, an additional 11 statements reached consensus (5 yes, 6 no). The panel agreed that there was insufficient evidence for 134 (60.4%) of the statements, and were unable to agree on the outcome of the remaining statements.CONCLUSIONS: This study provides information on the current expert consensus on dietary nitrate, which may be of value to athletes, coaches, practitioners and researchers. The effects of dietary nitrate appear to be diminished in individuals with a higher aerobic fitness (peak oxygen consumption [V̇O2peak] > 60 ml/kg/min), and therefore, aerobic fitness should be taken into account when considering use of dietary nitrate as an ergogenic aid. It is recommended that athletes looking to benefit from dietary nitrate supplementation should consume 8-16 mmol nitrate acutely or 4-16 mmol/day nitrate chronically (with the final dose ingested 2-4 h pre-exercise) to maximise ergogenic effects, taking into consideration that, from a safety perspective, athletes may be best advised to increase their intake of nitrate via vegetables and vegetable juices. Acute nitrate supplementation up to ~ 16 mmol is believed to be safe, although the safety of chronic nitrate supplementation requires further investigation. The expert panel agreed that there was insufficient evidence for most of the appraised statements, highlighting the need for future research in this area.
|
|
| 7. |
- Ørtenblad, Niels, et al.
(författare)
-
Role of glycogen availability in sarcoplasmic reticulum Ca(2+) kinetics in human skeletal muscle
- 2011
-
Ingår i: Journal of Physiology. - : Wiley. - 0022-3751 .- 1469-7793. ; 589:3, s. 711-725
-
Tidskriftsartikel (refereegranskat)abstract
- Little is known about the precise mechanism that relates skeletal muscle glycogen to muscle fatigue. The aim of the present study was to examine the effect of glycogen on sarcoplasmic reticulum (SR) function in the arm and leg muscles of elite cross-country skiers (n = 10, (V) over dot(O2 max) 72 +/- 2 ml kg(-1) min(-1)) before, immediately after, and 4 h and 22 h after a fatiguing 1 h ski race. During the first 4 h recovery, skiers received either water or carbohydrate (CHO) and thereafter all received CHO-enriched food. Immediately after the race, arm glycogen was reduced to 31 +/- 4% and SR Ca2+ release rate decreased to 85 +/- 2% of initial levels. Glycogen noticeably recovered after 4 h recovery with CHO (59 +/- 5% initial) and the SR Ca2+ release rate returned to pre-exercise levels. However, in the absence of CHO during the first 4 h recovery, glycogen and the SR Ca2+ release rate remained unchanged (29 +/- 2% and 77 +/- 8%, respectively), with both parameters becoming normal after the remaining 18 h recovery with CHO. Leg muscle glycogen decreased to a lesser extent (71 +/- 10% initial), with no effects on the SR Ca2+ release rate. Interestingly, transmission electron microscopy (TEM) analysis revealed that the specific pool of intramyofibrillar glycogen, representing 10-15% of total glycogen, was highly significantly correlated with the SR Ca2+ release rate. These observations strongly indicate that low glycogen and especially intramyofibrillar glycogen, as suggested by TEM, modulate the SR Ca2+ release rate in highly trained subjects. Thus, low glycogen during exercise may contribute to fatigue by causing a decreased SR Ca2+ release rate.
|
|
| 8. |
- Karltun, Linley Chiwona, et al.
(författare)
-
Migration and the Food Environment
- 2017
-
Ingår i: Ending Childhood Obesity. - Uppsala, Sweden. ; , s. 20-25
-
Annan publikation (övrigt vetenskapligt/konstnärligt)
|
|
| 9. |
- Mackay, Heather, 1976-
(författare)
-
A feminist geographic analysis of perceptions of food and health in Ugandan cities
- 2019
-
Ingår i: Gender, Place and Culture. - : Routledge. - 0966-369X .- 1360-0524. ; 26:11, s. 1519-1543
-
Tidskriftsartikel (refereegranskat)abstract
- This article contributes to a feminist geographic analysis of how urban food and health environments and non-communicable disease experience may be being constructed, and contested, by healthcare professionals (local elites) in two secondary Ugandan cities (Mbale and Mbarara). I use thematic and group interaction analysis of focus group data to explore material and discursive representations. Findings make explicit how healthcare professionals had a tendency to prescribe highly classed and gendered assumptions of bodies and behaviours in places and in daily practices. The work supports the discomfort some have felt concerning claims of an African nutrition transition, and is relevant to debates regarding double burden malnutrition. I argue that a feministic analysis, and an intersectional appreciation of people in places, is advantageous to food and health-related research and policy-making. Results uncover and deconstruct a dominant patriarchal tendency towards blaming women for obesity. Yet findings also exemplify the co-constructed and malleable nature of knowledge and understandings, and this offers encouragement.
|
|
| 10. |
- Mackay, Heather, 1976-
(författare)
-
Food Sources and Access Strategies in Ugandan Secondary Cities : An Intersectional Analysis
- 2019
-
Ingår i: Environment & Urbanization. - : SAGE Publications. - 0956-2478 .- 1746-0301. ; 31:2, s. 375-396
-
Tidskriftsartikel (refereegranskat)abstract
- This article arises from an interest in African urbanization and in the food, farming and nutritional transitions that some scholars present as integral to urban life. The paper investigates personal urban food environments, food sources and access strategies in two secondary Ugandan cities, Mbale and Mbarara, drawing on in-depth interviews and applying an intersectional lens. Food sources were similar across dimensions of difference but food access strategies varied. My findings indicate that socioeconomic circumstance (class) was the most salient influence shaping differences in daily food access strategies. Socioeconomic status, in turn, interacted with other identity aspects, an individual’s asset base and broader structural inequalities in influencing urban food environments. Rural land and rural connections, or multispatiality, were also important for food-secure urban lives. The work illuminates geometries of advantage and disadvantage within secondary cities, and highlights similarities and differences between food environments in these cities and Uganda’s capital, Kampala.
|
|
