Dr. Sharma's Obesity Notes

After an exhausting week of jam-packed sessions at the 3rd Canadian Obesity Summit last week, it is time to look back at some of the initiatives and projects presented at the Summit.

One particular exciting event was a cooking demonstration by SuperChefs of the Universe hosted by the Starwoods Group in its Westin Bayshore kitchen.

This Vancouver-based initiative that is rapidly turning into a global movement describes itself as follows:

“SuperChefs Entertainment Inc. is a company dedicated to teaching kids invaluable cooking skills and promoting healthy eating habits by focusing our animated characters, the SuperChefs of the Universe, on entertaining and educating young children, in all forms of media, about the power and the fun that comes from the joy of cooking, eating nutritious foods and daily exercise and the lifelong impact they can have on their lives.”

SuperChefs kids and Executive Chefs, including Chef Andrew George (World Culinary Gold Olympian), Chef Victor Bongo (Awarded Top Ten Chefs in Canada and soon to be seen on Chopped!), and Dr. Greg Chang (Founder/Creator SuperChefs Cookery for Kids).

A young SuperChef working with Chef Victor Bongo to prepare crepes

SuperChefs checking out Dr. William Dietz’s (former Director of the US Centre for Disease Control) crepe flipping skills

Dr. Hasan Hutchinson, Director General of the Office of Nutrition Policy and Promotion within the Health Products and Food Branch of Health Canada, trying his hand at flipping crepes

For more on the SuperChefs – check out their website and activities.

AMS
Vancouver, BC

One of the more persistent “myths” about obesity is that overweight and obese kids are big largely because of their reduced levels of physical activity.

As regular readers may recall, this was not borne out by previous surveys on physical activity, where the relationship between physical activity and body size have been rather inconsistent.

Now a paper by Vorwerg and colleagues from the University of Leipzig, Germany, published in PLoS One, again fails to find a significant relationship between physical activity levels and body weight in German pre-schoolers.

Thus, based on measurements of physical activity using accelerometers, boys generally clocked about an extra hour of vigorously activity per week compared to girls and overall activity levels were significantly lover on weekends than on weekdays.

However, there was no relationship between body weight and levels of physical activity or levels of daily media consumption.

Rather, both body weight and media consumption were inversely associated with decreasing socioeconomic class, which in fact, turned out to be the only variable that had an ‘independent’ impact on body weight.

Thus, the authors conclude that weight status of preschoolers is considerably influenced by socioeconomic factors, but not by physical activity levels.

These findings certainly do not argue against increasing physical activity levels in all pre-schoolers – this is sure to have many health benefits – just perhaps not on body weight.

Will the kids get fitter? Yes! Less fat? Probably not!

AMS
Edmonton, Alberta

Vorwerg Y, Petroff D, Kiess W, & Blüher S (2013). Physical Activity in 3-6 Year Old Children Measured by SenseWear Pro®: Direct Accelerometry in the Course of the Week and Relation to Weight Status, Media Consumption, and Socioeconomic Factors. PloS one, 8 (4) PMID: 23573273

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To those, who have been to any of my “Dr. Sharma Shows“, my interest in the topic of resilience should come as no surprise.

If my work with obese clients has taught me anything, it is the simple fact that for those who use food as a coping strategy, the solution will not lie in diet or exercise plans. To them, the discussions for and against sugar-sweetend beverages and the pros or cons of resistance vs. endurance training are irrelevant to a point that makes these discussions almost funny – they seem to exist in a parallel universe.

Indeed, the solution to emotional overeating (including its most severe form namely “binge eating disorder”), can only come from recognizing the relationship between their emotions and their eating behaviours, with the goal to ultimately developing healthier, non-food coping strategies.

Not that these will necessarily lead to weight loss – as I always hasten to point out – eliminating the cause of weight gain does not translate into weight loss – it merely translates into stopping the gain and often, a far better quality of life.

But then again, stopping the gain should be the first step in any weight management program and skipping this step (or fast-forwarding through it), can only guarantee failure.

This is why I firmly believe that for all of us working in the field of obesity, understanding the complex neurobiology of resilience (the successful adaptation and swift recovery after experiencing life adversities), is as essential as understanding the physiology of energy balance.

Readers interested in a rather comprehensive overview of resilience (in the context of mental health) are referred to a paper by Bart Rutten and colleagues from Maastricht University, published in Acta Psychiatrica Scandinavica.

In their extensive and systematic review of the literature, they find that the term “resilience” is used for phenomena ranging from susceptibility to mental health disturbances to adaptation and recovery from adverse experiences.

They describe three possible trajectories that can follow a severe stressor/trauma:

“…ranging from a trajectory showing consistent decline in mental health following exposure to adversity without subsequent recovery of mental health for a prolonged period of time, to a decline in mental health following the exposure that recovers quickly to preexposure levels of mental health and continues to increase thereby surpassing preexposure levels of mental health. This latter response, known as post-traumatic growth, is a very interesting form of adaptation, in which the individual may have obtained a better understanding of his life, possibly from a new perspective, or may have learned to respond efficaciously to similar challenges in the future.”

As the authors point out,

“The neurocircuitries mediating the stress response and reward experience are thought to be crucially involved in the neurobiology of resilience. The efficiency in activating and terminating the response to stress is regulated by elaborate negative feedback systems in the brain and the rest of the body….The hypothalamus–pituitary–adrenal (HPA) axis, the sympathetic nervous system (SNS) and the dopaminergic and serotonergic neurotransmitter systems are major neural systems that govern the stress response..”

There is indeed increasing recognition that experiences profoundly effect brain plasticity:

“These experience-dependent mechanisms regulate the sensitivity and plasticity of the central nervous system and act at several biological levels (likely partly in parallel with each other): i) cellular changes such as neurogenesis, pruning and sprouting of synapses, myelination of axons and alterations to the number of dendritic spines, ii) subcellular changes, such as alterations to the cytoskeleton and the extracellular matrix and changes in the levels of intracellular signalling molecules and iii) molecular (epi) genetic changes such as DNA methylation and chromatin changes. Thus, one can envision that aberrant regulation at any of these levels may moderate risk for and resilience to the consequences of stress and that resilience thus depends on a range of environmental and genetic factors during life.”

Although adverse life experiences can occur and have effects throughout life, there are key times of developmental vulnerability – times, when adverse effects can have “permanent” effects on the individual.

The first period is in early childhood development – beginning right after birth.

In animal studies,

“…parental care during early life induces long-term changes in behaviour as well as in gene expression mediated by epigenetic changes in the hippocampus of rats. As compared with offspring of mother rats with low-nurturing behaviour, offspring of high-nurturing mother rats (displaying more licking and grooming behaviour) were less anxious, had attenuated corticosterone responses after stress exposure and expressed higher levels of the glucocorticoid receptor (GR) in the hippocampus in adulthood. Interestingly, the methylation level of the promoter region of Nr3c1, i.e. the gene encoding the GR, was elevated already the first week of life in the hippocampus of pups that received less and lower quality nurturing , an effect that persisted into adulthood…..other studies have shown that the mother–infant interaction has long-lasting effects on endocrine and behavioural responses later in life.”

“Another interesting line of research has explored the effects of maternal separation on biology and behaviour. Although most studies observed detrimental effects of maternal separation, studies where rat pups were separated from their mother for a very brief period, i.e. 15 min, indicated that these pups, compared with non-separated pups, were more stress resistant later in life. Interestingly, as compared with offspring not separated from their mother for these brief spells in very early life, animals with brief spells of maternal separation showed higher levels of glucocorticoids (GCs) directly after stress exposure in adulthood, with a fast return to basal levels. Thus, type, severity and/or duration of stressful experience early in life seem to influence differential stress reactivity later in life.”

The other vulnerable period appears to be in adolescence, particularly in response to the “social defeat paradigm”,

“In the social defeat paradigm, male test mice aged 6–10 weeks (corresponding to puberty and adolescence in humans) are placed into the territory of a larger and more aggressive resident mouse. The mice are left in this physically and socially stressful situation for approximately 10 min, which leads to subordinate behaviour of the test mouse. After these 10 min, the mice remain in sensory (but not physical contact) with each other for the rest of the day, and the procedure is repeated for 10 consecutive days. The experimental paradigm is known to induce anxiety-like behaviour, prolonged elevations in corticosterone levels and a range of other molecular and cellular changes. Mice that were subjected to chronic social defeat stress furthermore showed a prolonged reduction in orexin signalling in the hypothalamus. Orexin has been implicated in arousal and feeding behaviour, but more recently also in the mesolimbic reward pathway… Although all mice have the same genetic background, and are exposed to similar conditions of social defeat, this experimental paradigm has repeatedly been shown to elicit two distinct responses in the domain of social behaviour: one group of mice displaying social avoidance after the social defeat experience (these mice are called ‘susceptible’), whereas a second group of mice still showing social interaction rates that are comparable with the control group (and is therefore called ‘unsusceptible’ or ‘resilient’). Thus, only a distinct subpopulation (i.e. the ‘susceptible’ mice) displays social avoidance and behavioural signs of anhedonia, while all exposed animals (‘susceptible’ and ‘unsusceptible’ mice) show elevated corticosterone levels and increased anxiety-like behaviour.”

As discussed in the above quote, it is apparent that the molecular changes associated with the response to this stress paragigm are intimately related to the very neurons and areas of the brain known to be linked to eating behaviour. Thus, the impact of adverse life events, whether this is early separation from the mother or exposure to school yard bullying, on eating behaviour and weight trajectories should come as no surprise to anyone working in the field.

Based on their review of the literature, the authors identify three rather consistent predictors of resilience include secure attachment, positive emotional experiences and having a purpose in life.

I will discuss these factors individually in subsequent posts – stay tuned.

AMS
Edmonton, AB

Perhaps one of the most frustrating experiences encountered by patients trying to lose weight, is the variation in weight loss between individuals. Thus, it is not uncommon to see one person easily shedding the pounds, while another, with similar or even greater effort, making little progress.

While, as clinicians it may be tempting to simply blame this on “non-compliance”, a paper by Adriana Moleres and colleagues from the University of Navarra, Pamplona, Spain, published in the FASEB Journal, suggestions that a significant part of this variable response may be attributable to differences in DNA methylation.

As readers may know, methylation of DNA is an important epigenetic phenomenon, whereby certain genes are turned on or off (often forever). These epigenetic changes tend to happen during certain times in human development, including early fetal development and adolescence.

In the current study, Moleres and colleagues compared DNA methylation between adolescent high and low responders to a 10 week multidisciplinary weight loss program.

Using methylation microarrays, the researchers identified five regions located in or near AQP9, DUSP22, HIPK3, TNNT1, and TNNI3 genes that showed significantly differnt methylation levels between high and low responders. Interestingly, the AQP9 and HIPK3 genes have previously been associated with obesity or weight-loss responses.

They were also able to calculate a methylation score that was significantly associated with changes in weight, BMI-SDS, and body fat mass loss after the treatment.

While it is difficult to determine the actual functional effect or mechanisms underlying these epigenetic DNA variations, the findings do point to a “biological” reason that may determine weight loss response to diet and lifestyle interventions.

As I’ve said before, in weight management, one size does not fit all.

AMS
Edmonton, AB

Moleres A, Campión J, Milagro FI, Marcos A, Campoy C, Garagorri JM, Gómez-Martínez S, Martínez JA, Azcona-Sanjulián MC, Martí A, & on behalf of the EVASYON Study Group (2013). Differential DNA methylation patterns between high and low responders to a weight loss intervention in overweight or obese adolescents: the EVASYON study. FASEB journal : official publication of the Federation of American Societies for Experimental Biology PMID: 23475851

Moving beyond its expected focus on food and physical activity, I certainly find it refreshing that the Ontario Healthy Kids Panel’s report No Time to Wait: The Healthy Kids Strategy released yesterday, also touches on the issue of childhood mental health.

Thus, the authors do make the point that,

“Children and youth who enjoy good mental health respond better to life’s challenges and make healthier choices. We can foster children’s resilience by focusing on positive relationships, experiences and inner strengths such as values, skills and commitments. We can create a strong sense of belonging at home, in school and in communities; build on children’s strengths and competency; and encourage their autonomy and ability to make decisions that will enhance their health and well-being.”

They also include the following in their recommendations,

“Because of the strong links between mental health problems and unhealthy weights, the Healthy Kids Strategy should work closely with the province’s Mental Health and Addictions Strategy, focusing particularly on helping children develop the confidence, self-esteem, resilience and coping skills that will improve their mental health and empower them to make healthy choices throughout their lives. Youth should be actively involved in planning and implementing these strategies.”

Regular readers will certainly appreciate that I have always championed the notion that obesity and mental health are two sides of the same co-epidemic and that strategies to address the root cause of either of these problems will hopefully help address the other.

Readers may well recall that last year, the Canadian Obesity Network together with a number of partners released the Toronto Charter on Obesity and Mental Health – hopefully elements form this charter will find their way to decision makers as they decide which of the panel recommendations to focus on.

I, for one, have no doubt that attention to mental health and resilience (in both the parents and their kids) will be a key determinant of the success of this strategy.

AMS
Edmonton, AB