Stress and its consequences on health behaviors in children was discussed. Studies found that stress can deteriorate diet and physical activity. Higher stress was associated with increased adiposity, mediated by cortisol and lifestyle factors. Lifestyle interventions combining nutrition, activity and psychology were effective for treating childhood obesity. Future projects aim to study emotion regulation interventions, the role of gut bacteria, stress and diet around exam periods, and lifestyle factors in cognitive and cardiovascular aging. Collaborations with other researchers will further these projects.
Stress and health behaviors in children: an extensive overview and some own results
1. Funded by the EC, FP 6, Contract No. 016181 (FOOD)
Stress and health behaviors in children.
nathalie.michels@ugent.be
@MichelsNathalie
Nathalie Michels
Department of Public Health
Ghent University, Belgium
7. Medical consequences
Cfr. definition
stressor: acute
reaction: normal = short
stressor: chronic, unpredictable, uncontrollable
reaction: abnormal = chronic or no
1) 2)
3) 4)
“good” “bad”
7
McEwen. NEJM 1998
8. 2. Autonomic activity
-> fight or flight
Medical consequences
Cfr. endocrinology
1. Cortisol
-> energy release
Growth
Reproduction
Immune function
Availability of
glucose,
protein and fat
Digestion
Reproduction
Heart rate
Blood pressure
Respiration
Muscle supply
8
Charmandari. Annu Rev Physiol 2005
9. 1. Cortisol
cortisol hormone in serum, urine, saliva, hair and nails
9
short-term
clinical setting
invasive
freezing
mid-term
also at home
less invasive
long-term
room temperature
Stress measurements:
Cortisol
Vanaelst et al. Epidemiological approaches to measure childhood stress;
Paediatric Paediatric and Perinatal Epidemiology, 2012, 26, 280–297
10. 2. Autonomic activity
a) Adrenaline and noradrenaline
b) Heart rate variability
c) Salivary amylase
d) Skin conductance
10
Stress measurements:
Autonomic
11. Stress and its consequences
Mechanisms with lifestyle & obesity
From stress to obesity
Fat storage
Diet
Activity
Sleep
From obesity/diet to stress
Own results
Implications
Future projects
Overview
11
19. Mechanisms stress->obesity
2) Diet: research example
Roemmich 2011 Eating behaviors
19
Vulnerable if high
restraint or high body fat
40 children 8-12y
Food intake after laboratory stress
Unhealthy food & healthy food
20. Mechanisms
3) Activity
Less motivation
Less time
Used as coping
Euforic effect
A way of coping to reduce stress
Decreasing stress endocrine respons
Social support
Performance and time pressure
Energy is mobilized during stress as preparation for activity (fight/flight)
-> Physical activity (= energy expenditure) is ideal stress reaction
Tsatsoulis Ann NY Acad Sci
200620
21. Mechanisms stress->obesity
3) activity: research example
Roemmich 2003 Obesity research; Balantekin 2012 Appetite
21
30 children 8-12y
After laboratory stressor: free choice to food, activity and TV
Different effect depending on reactivity and usual activity
22. Mechanisms
4) Sleep
Hormonal: cortisol inhibits sleep
and influences sleep phases
(cfr circadian rhythm of cortisol)
Psychological: problems to fall
asleep due to worrying and
anticipation
Practical: lack of time
Hormonal: short sleep increases
stress hormones
Neural: lowered performance
Neural: lowered mood
(Psychological: sleep related
stress)
Sleep is the metabolic antagonist of stress!
Sleep duration AND quality (sleep latency, awakenings, time in sleep phases)!
Akerstedt Scand J Work Environ Health 2006
Buckley JCEM 200522
32. Results:
stress - adiposity
More adiposity
more stress
β= 0.480
p<0.001
Only after moderation by
cortisol and lifestyle:
More stress
more or less adiposity
32
Michels N, et.al 2015 Psychosomatic Medicine 77(1):50-8
34. Looking broader:
Metabolic syndrome
34
Not significant
More behavioral problems (β=0.089)
Low parasympathetic activity (β=-0.104)
More behavioral problems (β=0.079)
Overall cortisol output (β=0.184)
More stressors (β=0.122)
High cortisol awakening response (β=0.124)
Michels et al. In review. Cardiovascular Research
1
2
3
4
35. Conclusion
35
Lessons learned:
1)Stress deteriorates diet and influences
physical activity
2)Not everybody reacts to stress in the
same way
3)lifestyle & cortisol = vulnerability
/protective factors in stress-induced
adiposity
4)Adiposity can increase stress even in a
low-obesity population
Multidisciplinary research
Longitudinal research + complexity
Use of biomarkers
Also in children
36. Stress and its consequences
Mechanisms in relation to diet & obesity
Own results
Implications
Future projects
Overview
36
37. Implications
stress coping skills,
social support,
self-esteem
activity encouraging,
healthy food zone
with awareness for
emotional eating
psychosocial
support in
obese people
pharmacological,
cognitive behavioural therapy,
relaxation,
physical activity
37
identify underlying
problem
39. 39
Katterman 2014 Eating behaviors
Implications: mindfulness?
Based on systematic review:
Significant effect on emotional or binge eating? 9/11
Significant effect on weight? 4/10
Most effective: combined mindfulness, CBT and mindful eating
Always include diet and activity intervention
More research necessary: increase N, follow-up,…
41. Parents
make an example by own eating style
lower availability of unhealthy food
parental stress as risk factor e.g. fast food consumption; vegetables
(Renzaho, Kumanyika et al. 2011, Parks, Kumanyika et al. 2012)
Community
activity constrained by external factors: policy, physical environment (Dollman, Norton 2005)
eating in absence of hunger stimulated by social food norms (Lowe and Butryn 2007)
high expectations/pressure
But not only focus on child
41
42. Stress and its consequences
Mechanisms with lifestyle & obesity
Own results
Implications
Future projects
Overview
42
43. 43 start januari 2017
1. Emotion regulation intervention
Collaboration with Prof. Caroline Braet (UGent, Psychology)
- Contrasting groups
- Intervention
45. 2. The gut: theory
45
Moloney 2014 Mamm Genome
1 2
21 3Gut -> brain
Brain -> gut
46. 46 Master thesis 2016-2017
3. Examination stress and diet
Examination time
at university
Less energy-intake
More energy-intake
or unhealthier food- Demographics
- Emotional eater
- Reward sensitivity
- Maladaptive coping
- Physical activity
- Social environment
47. 47
4. Better lifestyle in cognitive and
cardiovasular aging
Applying for national grant
12-18y
20-30y
48. National outside our unit Nutrition and Food safety
Prof. Tom Van de Wiele (LabMET, UGent): microbiota
Prof. Caroline Braet (Developmental psychology): emotion regulation
Prof. Ernst Rietzschel (UGent): cardiology
Psychiatry unit UZGent: depression
Prof. Tim Nawrot (UHasselt): telomere
International
Dr. Livia Carvalho (University college London)
Rovira i Virgili University of Tarragona, Spain
Dr. Inge Huybrechts (Internation Agency for Research on Cancer)
Prof. Wolfgang Ahrens (Bremen) IDEFICS/IFamily
Dr. Jardena Puder (Lausanne)
Prof. Luis Moreno (Zaragoza) HELENA study
….
48
Related collaborations
nathalie.michels@ugent.be
Editor's Notes
Sapolsky
Sapolsky
But back to business, why does stress stimulates this snacking? The main reasons are the increased reward sensitivity and the increased appetite.
So, again we have the high cortisol response due to stress. Cortisol stimulated the reward pathways especially when one is on cognitive restrained. More importantly, cortisol influences appetite hormones. Is upregulated NPY (neuropeptide Y) which increased appetite and reward. Furthermore it dysregulated insulin and leptin. These two decrease appetite and reward, but due to the dysregulation the body becomes resistant and appetite and reward will be increased.
So, insulin, leptin and NPY are important hormones explaining the effect on diet. Nevertheless, recent literature also suggest other hormones like adiponectine (dysregulated: anorexigen) and ghreline (orexigen), but that would bring is too far.
Next pathway is the physical activity pathway.
Back in the prehistoric centuries, a human that was stressed due to an animal for example a tiger will be happy that his body reacts immediately on this stressor. The body will mobilize energy as prepartion for activity: the fight or flight response. In our century, this energy mobilization is not always necessary for our stressors, so we just store the energy. Consequently physical activity should be an indeal reaction to stress since it will burn the mobilized energy.
In literature we can find some reasons that stress influences activity: stressed people probably will not have the motivation or the time to be active resulting in decreased activity. Nevertheless, physical activity can be used as a way of coping by some people.
But the relation could also be seen from the other direction: physical activity influencing stress. This is the direction for which most literature exists. Physical activity can give you an euforic feeling, it is a perfect way to cope with stress, it decreased the stress endocrine response and it will give you also some social support. All factors will decrease your stress level. Again, it could also increase your stress level if there is performance and time pressure, but literature mostly does not support this effect.
All together, the principal hypothesis is that stress decreases activity and this increases stress.
Then the last pathway: sleep. We have to consider that sleep is the metabolic antagonist of stress. During sleep we have increase growth hormone, testosteron, a lower metabolism, a lower blood flow and heart rate. All the opposite compared to stress.
So it would not be suprising that we link these two, again bidirectional.
Stressed people may have problems to fall asleep due to worrying or anticipation of the next day. Stressed people due to high workload will have a lack of time to sleep and will go to bed very late. Moreover the activiated cortisol system inhibits sleep and influences important sleep phases (REM, SWS). This makes sense if we consider the circadian rhythm cortisol has: a peak in the morning and very low in the night.
Short sleep can also increase stress due to cortisol increased and a lowered performance and mood the next day. Rarely, we also see sleep related stress: being stressed since they have problems to fall asleep.
In all of these hypotheses, we have to think about sleep duration but also sleep quality such as long sleep latency, many awakenings or short time in important sleep phases such ad the REM phase.
