Monday, September 29, 2014

Does Lean Tissue Have More To Say About Your Health Than Your Body Fat?

Carla Prado, PhD,  Assistant Professor and CAIP Chair in Nutrition, Food and Health, University of Alberta, Edmonton, Canada

Carla Prado, PhD, Assistant Professor and CAIP Chair in Nutrition, Food and Health, University of Alberta, Edmonton, Canada

The common assumption is that people with more body fat are at greater risk for illness and overall mortality.

Surprisingly, an increasingly robust body of evidence now suggests that how much lean tissue you have may be far more important for your health than the amount of body fat.

This evidence as well as the methodologies used to study lean body mass are discusses in a paper by Carla Prado (University of Alberta) and Steve Heymsfield (Pennington Biomedical Research Center), in a paper published in the Journal of Parenteral and Enteral Nutrition.

As the authors point out,

“The emerging use of imaging techniques such as dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and ultrasound imaging in the clinical setting have highlighted the importance of lean soft tissue (LST) as an independent predictor of morbidity and mortality.

The paper discusses in depth the advantages and limitation of the many methods that can be used to assess body composition in research and clinical settings.

The paper also discusses the current definition and importance of sarcopenic obesity and notes that,

“The identification of different body composition phenotypes suggests that individuals have different metabolism and hence utilization of fuel sources.”

Thus,

“It is clear from emerging studies that body composition health will be vital in treatment decisions, prognostic outcomes, and quality of life in several nonclinical and clinical states.”

My guess is that it will not just be the absolute or relative amount of lean tissue mass that is important. Rather, similar to the increasingly recognised role of differences amongst fat depots, I would assume that different lean soft tissue depots may well play different roles in metabolic health.

@DrSharma
Charlottetown, PEI

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Monday, September 22, 2014

What Can We Learn From the Sweetener and Gut Bug Study?

sharma-obesity-gut-buts1Last week, a paper by Jotham Suez and colleagues on the potential detrimental effect of artificial sweeteners (particularly saccharin) on glucose homeostasis, published in Nature grabbed media attention worldwide.

Using an elegant series of experiments, the research showed that saccharin not only appears to negatively affect glucose metabolism in mice, but does so through its effects on gut bugs.

Potential relevance to humans was demonstrated by exposing volunteers to 120 mg of saccharin a day for 7 days and then transplanting the stool of the four (out of seven) participants, who showed decreased glucose tolerance, to germ-free mice.

In their conclusions, the authors speculate that the widespread consumption of artificial sweeteners (as a means to prevent obesity and/or diabetes) may have played a paradoxical role in promoting these very health problems.

While that may or may not be the case (given that all we have is evidence in mice and short-term finding from a handful of humans), I find these observations most interesting for one simple reason alone and that is the demonstration that chemical composition of the diet can alter gut bacteriomes, which in turn can significantly affect metabolism.

Whether or not artificial sweeteners may have significantly altered the gut bacteria of people across the world (leading to obesity in Africa, India, South America and elsewhere) may not be entirely plausible but, if indeed sweeteners can do this, there are probably much more likely culprits in our modern diets.

For one, I would begin by suspecting the rather liberal use of antibiotics both in animal husbandry as well as human infection. Next, I would wonder about the widespread use of preservatives and pesticide. Finally, I’d wonder about the very likely impact of all the other chemicals including personal hygiene products and disinfectants in our environment on our intestinal flora (does washing your hands make you obese?).

If there is one thing that I learn from this study, it is the fact that we must now take into consideration a wide range of factors that can potentially alter our susceptibility to obesity and/or diabetes by changing our gut bugs.

Incidentally, the gut bugs are not just influenced by environmental or food-borne chemicals – the very foods we eat can substantially affect our gut bugs, which have now been implicated in everything from Alzheimer’s and autism to arthritis and cancer.

While every new area of research is often accompanied by considerable hype (promoted both by the media and the researchers themselves), this will probably be an interesting space to watch.

@DrSharma
Edmonton, AB

ResearchBlogging.orgSuez J, Korem T, Zeevi D, Zilberman-Schapira G, Thaiss CA, Maza O, Israeli D, Zmora N, Gilad S, Weinberger A, Kuperman Y, Harmelin A, Kolodkin-Gal I, Shapiro H, Halpern Z, Segal E, & Elinav E (2014). Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature PMID: 25231862

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Monday, September 15, 2014

Update on New Medications for Obesity

sharma-obesity-fda4Last week, while I was off on a brief holiday, two important events took place in the US with regard to obesity medications.

On September 10, the US-FDA granted approval for Contrave, a fixed combination of bupropion and naltrexone, two centrally active compounds, also used in the treatment of addictions.

Then, on September 11, an advisory panel appointed by the FDA, voted strongly in favour of approving the GLP-1 agonist liraglutide at the 3.mg dose for the treatment of obesity.

These two new entities would bring the currently approved prescription medications for the treatment of obesity in the US to six – a dramatic change from just a couple of years ago.

This is still a long shot away from the many effective treatments we have for treating other common conditions (e.g. there are more than 20 prescription medications approved for treating diabetes and almost 100 compounds for the treatment of hypertension).

Why would we need this many different medications for obesity? For the simple reason that not everyone will respond favourably or tolerate all of these compounds.

Given that obesity is a remarkably heterogeneous disorder and that these drugs have distinctly different modes of action, I would not expect all of these medications to work in all individuals.

It is also important to note that all of these drugs work best when combined with intense behaviour modification – no pill will ever serve as a substitute for a healthy diet and a daily dose of moderate to vigorous physical activity. But we also know that the latter alone, will rarely produce sustainable weight loss in the long-term.

Obviously, given the chronic nature of obesity, medications for obesity will need to be used long-term in the same manner that we use medications to treat other chronic conditions (e.g. diabetes, hypertension, etc.).

This means that we will need more long-term data on the efficacy and safety of these compounds.

Nevertheless, there is reason to hope that for many people with obesity related health problems, these new obesity medications will provide much-needed therapeutic options.

@DrSharma
Vienna, Austria

Disclaimer: I have served as a paid consultant and/or speaker for the makers of Contrave and liraglutide.

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Tuesday, September 2, 2014

Can Weight Loss Supplements Promote Weight Gain?

sharma-obesity-weight-loss-supplementsApart from the fact that there are indeed no weight-loss supplements that will help you lose more than the weight of the money in your back pocket (a fact that even Dr. Oz had to admit to at a recent senate inquiry into the rubbish he promotes on his shows), there may be reason to suspect that the use of such supplements may in fact do the opposite.

Thus, a rather simple experiment by Yevvon Chang and Wen-Bin Chiou from Tunghai University, Taichung, Taiwan, published in Nutrition, suggests that taking a (supposed) weight-loss supplement may actually lead to greater caloric intake.

This field study was conducted in 70 volunteers, who were randomised to taking a either placebo or a weight-loss supplement (the same placebo) and were then exposed to a buffet meal.

On average, participants presumably taking weight loss supplements ate a greater number of food items than did control subjects (overall about 30% more food). They also tended to chose less healthy items than the control group.

This effect tended to be strongest in those subjects who had a more positive attitude towards taking supplements for weight loss (those with the most positive attitude eating almost 3 times more food items).

Or, as the authors summarise,

“…the results supported our hypothesis that taking weight loss supplements was associated with an inclination to eat more food. This link was driven by perceived progress toward the goal of weight reduction. The liberating effect of taking weight loss supplements on food consumption became more prominent as attitudes toward this kind of supplement became more positive.”

Obviously, it is hard to extrapolate from such a short-term experiment to what happens over time – especially when people do follow the lifestyle recommendations that come with most supplements (eat-less-move-more).

This study certainly is in line with the recent observation that people who take statins to lower their blood cholesterol levels tend to eat unhealthier diets and may in fact end up gaining more weight than people who don’t.

Thus, it may be time to study the “fattening” effect of weight-loss supplements. Perhaps the only reason that we have not yet observed this effect in larger studies is because very few people stay on these nonsensical agents for more than a few weeks.

@DrSharma
Gambach, Germany

ResearchBlogging.orgChang YY, & Chiou WB (2014). The liberating effect of weight loss supplements on dietary control: A field experiment. Nutrition (Burbank, Los Angeles County, Calif.), 30 (9), 1007-10 PMID: 24976417

 

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Thursday, August 28, 2014

Call For Abstracts: Canadian Obesity Summit, Toronto, April 28-May 2, 2015

COS2015 toronto callBuilding on the resounding success of Kananaskis, Montreal and Vancouver, the biennial Canadian Obesity Summit is now setting its sights on Toronto.

If you have a professional interest in obesity, it’s your #1 destination for learning, sharing and networking with experts from across Canada around the world.

In 2015, the Canadian Obesity Network (CON-RCO) and the Canadian Association of Bariatric Physicians and Surgeons (CABPS) are combining resources to hold their scientific meetings under one roof.

The 4th Canadian Obesity Summit (#COS2015) will provide the latest information on obesity research, prevention and management to scientists, health care practitioners, policy makers, partner organizations and industry stakeholders working to reduce the social, mental and physical burden of obesity on Canadians.

The COS 2015 program will include plenary presentations, original scientific oral and poster presentations, interactive workshops and a large exhibit hall. Most importantly, COS 2015 will provide ample opportunity for networking and knowledge exchange for anyone with a professional interest in this field.

Abstract submission is now open – click here

Key Dates

  • Abstract submission deadline: October 23, 2014
  • Notification of abstract review: January 8, 2014
  • Early registration deadline: March 5, 2015

For exhibitor and sponsorship information – click here

To join the Canadian Obesity Network – click here

I look forward to seeing you in Toronto next year!

@DrSharma
Montreal, QC

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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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