Thursday, March 27, 2014

Three Essential Ways in Which Melatonin Links to Energy Balance

sharma-obesity-pineal-glandAs a regular reader, you will be quite familiar with the emerging recognition of sleep (or rather lack thereof) as an important determinant of weight gain.

Melatonin, an evolutionary ancient molecule that, in mammals, is secreted from the pineal gland, is a hormone that plays a major role as a key regulator of the circadian cycle, along which  virtually all metabolic activities are coordinated.

A paper by José Cipolla-Neto and colleagues, published in the Journal of Pineal Research, provides a fascinating overview of how melatonin plays a significant role in energy metabolism.

Its first role relates to insulin secretion and action. Thus, melatonin is not only necessary for the proper synthesis and secretion of insulin, it also plays a role in the insulin-signalling pathway through its effects on GLUT4 receptors.

Secondly, as a powerful chronobiotic, it helps coordinate various metabolic processes so that the activity/feeding phase of the day is associated with higher insulin sensitivity whereas the rest/fasting phase is synchronized to lower insulin sensitivity.

Thirdly, melatonin plays an important role in regulating energy flow to and from fat stores and directly regulating the energy expenditure through the activation of brown adipose tissue and participating in the browning process of white adipose tissue.

The paper discusses how the reduction in melatonin production, as seen during aging, shift-work or night-time light exposure can induce insulin resistance, glucose intolerance, sleep disturbance and metabolic circadian disorganization, which together can lead to weigh gain.

Thus, the available data supports the notion that melatonin replacement therapy may provide a novel strategy to influence metabolism, at least in people with disruptions in their melatonin system.

Clearly, these notions need to be tested in well-controlled randomised trials but there certainly appears to be ample data to suggest that such a trial may well be worthwhile.

If you have taken melatonin or prescribed it to your patients, I’d certainly like to hear about your experience.

@DrSharma
Edmonton, AB

Hat tip to Sukie for pointing me to this article.

ResearchBlogging.orgCipolla-Neto J, Amaral FG, Afeche SC, Tan DX, & Reiter RJ (2014). Melatonin, Energy Metabolism and Obesity: a Review. Journal of pineal research PMID: 24654916

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Thursday, March 20, 2014

Sleep Duration Strongest Predictor of Health Risk in Obese Teens?

sharma-obesity-kid-sleep-book

If you had to guess the strongest predictor of cardiometabolic health risks in  obese teenagers, most of us would probably suspect their diet, sedentariness, or even mental health issues around mood, body image, or self-esteem.

Few of us would have guessed sleep duration.

But this is exactly what was found by Paul Gordon and colleagues from the University of Michigan, in a study published in the Journal of Pediatrics.

Although relatively small (the study included just 37 participants aged 11-17), the researchers went to great lengths to objectively measure habitual physical activity and sleep patterns as well as a wide range of cardiometabolic risk factors.

Amongst all of the measured variables, total sleep time and sleep fragmentation were inversely and independently associated with metabolic risk – the shorter the sleep time, the greater the risk.

This relationship remained robust even when the data were adjusted for various measures of physical activity, anthropometry, and adiposity.

Most subjects slept about seven hours a night, typically waking up at least once, with only five subjects getting the minimum recommended 8.5 hours of sleep each night.

Given what we now know about the profound impact of sleep deprivation on metabolism, physical activity and eating behaviours, it is astonishing that so little attention is being paid to the issue of sleep both in the public discourse of obesity as well as in clinical management of excess weight.

As I have said before, the three key drivers of obesity in my view are lack of time, lack of sleep and increased stress – everything else is either a consequence of or compounded by these factors.

Is it time for doctors to begin handing out sleep prescriptions?

@DrSharma
Edmonton, AB

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Tuesday, January 7, 2014

15 New Year Health Resolutions That Might Just Work

Arya Sharma Globe&Mail CartoonYesterday, the Globe & Mail ran a full page of Health Tips, one each from what they call “leading experts” (of who, I just happen to be one).

Here’s what the experts had to recommend:

1) Eat a pickle (rationale: fermented and preserved foods often contain bugs that may be good for you)

2) Don’t drink your calories (rationale: no benefits from drinking your calories that you cannot get from eating them)

3) Relax your mouth (rationale: unclenching you jaw helps you relax)

4) Walk (rationale: myriad health benefits of being more active)

5) Unplug (rationale: time to try other stuff – like reading a book)

6) Stop doing situps (rationale: bad for posture and your pelvic organs – does nothing to flatten your tummy)

7) Go to bed (rationale: sleep does wonders for your metabolism)

8) But set your alarm (rationale: waking up at the same time every day helps set your master clock)

9) Eat slowly (rationale: mindful slow eating is your best bet against overeating)

10) Breathe (rationale: slow breathing will help calm your nerves)

11) Clean up your kitchen (rationale: unprocessed and unsprayed plant-based whole foods are better for you)

12) Shake a leg (rationale: same as 4)

13) Use protection (rationale: helmets prevent brain injuries)

14) Invest in yourself (rationale: you need to make time to live healthier)

15) Take it outside (rationale: sunlight will improve your mood, memory and weight)

So there you go.

Don’t ask me for the actual evidence behind each of these – I’m sure it exists for what it’s worth – most of this stuff is really just common sense.

But then again, if things were really that easy, we’d be a nation of health nuts.

If you’ve made a resolution (and a full week into the New Year are still sticking with it) please feel free to share.

@DrSharma
Edmonton, AB

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Monday, November 11, 2013

Early to Bed Makes Kids Healthy, Wealthy and Wise?

CB101888Regular readers are by now well aware that lack of sleep (together with our obesogenic environment) may well be one of the central drivers of the obesity epidemic – kids not excluded.

So far much of this focus on sleep comes from compelling observational data, animal experiments and acute “physiological” studies in humans.

Now, a paper by Chantelle Hart and colleagues from Brown University, Providence, RI, published in Pediatrics, provides the first evidence from a randomised controlled trial that increasing sleep duration in kids may well have benefits in terms of eating behaviour and weight.

This study used a within-subjects, counterbalanced, crossover design, in 37 children, 8 to 11 years of age (27% overweight/obese) over 3 weeks.

Children slept their typical amount at home for 1 week and were then randomized to either increase or decrease their time in bed by 1.5 hours per night for 1 week, completing the alternate schedule on the third week.

Participants achieved a 2 hour, 21 minute difference in sleep period time resulting in a (reported) average reduction of 134 kcal/day less than with usual sleep.

This change in “appetite” was accompanied by a significant drop in leptin levels and even a 0.2 Kg reduction in body weight.

While sleep is unlikely to be the panacea for obesity management, these findings certainly reinforce the notion that one factor contributing to childhood obesity may well be the sleep-starvation of our kids that are deprived of sleep for all kinds of reasons, not least their “personal entertainment devices” (yes, even !! year olds have those!).

So, although an extra hour of sleep may not make your kid any wealthier or wiser (at least not based on this study), improved weight-related health may well be a benefit.

If you have any personal experience with how lack of sleep affect your or your kids appetite, I’d like to hear about it.

@DrSharma
Atlant, GA

ResearchBlogging.orgHart CN, Carskadon MA, Considine RV, Fava JL, Lawton J, Raynor HA, Jelalian E, Owens J, & Wing R (2013). Changes in Children’s Sleep Duration on Food Intake, Weight, and Leptin. Pediatrics PMID: 24190680

 

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Monday, July 8, 2013

Sleep Restriction Promotes Weight Gain in Humans

sharma-obesity-sleep-deprivationRegular readers already know that lack of sleep is increasingly seen as one of the major drivers of calorie overconsumption and weight gain.

Those, who remain sceptical may be interested in a paper by Andrea Spaeth and colleagues from the University of Pennsylvania, just published in SLEEP.

This, to date the largest randomised controlled trial of experimental sleep deprivation on eating behaviour shows that individuals who are sleep deprived will consume up to 500 extra calories per day compared to individuals who get adequate sleep.

The researchers studied 225 health adults randomised 8:1 to an experimental condition (including five consecutive nights of 4 h time in bed [TIB]/night, 04:00-08:00) or to a control condition (all nights 10 h TIB/night, 22:00-08:00).

Not only did sleep-restricted subjects gain more weight (0.97 kg) than control subjects (0.11 kg) but sleep-restricted weight gain was greater in African Americans than Caucasians and in males than in females.

Sleep-restricted subjects consumed 30% extra calories (over 550 additional calories mainly between 22.00 and 04.00), easily accounting for the observed weight gain.

Thus, the authors conclude that chronically sleep-restricted adults with late bedtimes may be more susceptible to weight gain due to greater daily caloric intake and the consumption of calories during late-night hours.

Given what we know about how sleep deprivation affects appetite and metabolism, these findings should come as no surprise.

Let us not forget that a key characteristic of “Westernised” society is significant sleep deprivation and about 40% of adult Canadians report at least one symptom of insomnia with over 10% of Canadians reaching for sleeping aids.

Reason enough to consider sleep (or rather lack thereof) a key driver of the obesity epidemic.

@DrSharma
Edmonton, AB

ResearchBlogging.orgSpaeth AM, Dinges DF, & Goel N (2013). Effects of Experimental Sleep Restriction on Weight Gain, Caloric Intake, and Meal Timing in Healthy Adults. Sleep, 36 (7), 981-990 PMID: 23814334

 

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In The News

Diabetics in most need of bariatric surgery, university study finds

Oct. 18, 2013 – Ottawa Citizen: "Encouraging more men to consider bariatric surgery is also important, since it's the best treatment and can stop diabetic patients from needing insulin, said Dr. Arya Sharma, chair in obesity research and management at the University of Alberta." Read article

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