Thursday, December 5, 2013

Weight Loss Supplements Exposed: Green Tea & Probiotics. Fat Loss, Energy Expenditure, Fat Oxidation, Sex & More

Yesterday at Starbucks: "I just ordered a bottle of probiotics!"
In view of the fact that all the feedback I got in response to the re-installment of the Short News was positive, I guess you won't mind if I use the chance and bundle the two soon-to-be-published weight loss studies from the British Journal of Nutrition into a Weight Loss Supplement Mini-Special of the SuppVersity Short News.

If you were actually sitting next to you, I would probably ask you, whether you'd prefer the good, or the bad news, first!? Well, I guess I'll start with the bad one, then: Green tea sucked - again!

ZERO effect of EGCG supplementation in overweight women

To examine the effects of green tea epigallocatechin-3-gallate (EGCG) on the changes in body composition (! not just weight), energy and substrate metabolism, cardiometabolic risk factors and liver function enzymes after an energy-restricted diet intervention in obese women, a group of researchers from the University of the Basque Country in Spain recruited a group of 83(!) obese (BMI 30-40 kg/m2) pre-menopausal women (Mielgo-Ayuso. 2013).

The women were randomly assigned to consume either 3x100 mg/d of EGCG or placebo (lactose) with each of their three main meals for 12 whole weeks. During those twelve weeks, all women followed a specifically designed low-energy mixed (55 % carbohydrates, 30 % lipids and 15 % proteins) diet that provided ca. 600 kcal/day energy less than the women would need to maintain their body weight. The energy content and macronutrient composition of diets were designed to achieve a weight loss of 0.5 to 1 kg per week, as it was observed by Davis et al. (2006) and Bantle et al. (2008) on very similar regimen. As the scientists point out, the "dietary instructions were reinforced weekly by a dietitian" (Mielgo-Ayuso), to optimise compliance.
Figure 1: Changes in body composition, energy expenditure and fat oxidation, left; changes in glucose, cholesterol metabolism and inflammation, right (Mielgo-Ayuso. 2013)
I am not sure how compliant the participants actually were, but in view of the fact that the women were advised not to change their physical activity habits during the energy restriction program, the relatively meager and statistically non-significant changes in body weight (-0·3 kg, p > 0.05) and fat mass (-0·7 kg, p > 0.05) are probably not really surprising. It is nice to see, though, that the women lost more fat than total mass - muscle loss was thus not an issue for the ladies.

What was not to be expected, though, - at least if you believe a single word of the hype about green tea supplements - were the non-existent effects of the purported weight loss supplement on  energy expenditure, fat metabolism, HOMA-IR (insulin sensitivity), total cholesterol, LDL-cholesterol, or triglycerides. In fact, the only good thing about the whole EGCG intervention was that the recently observed negative effects on the liver did not occur, either.

SIGNIFICANT Effect W/ 16 Million CFU of Nestlé's Lactobacillus rhamnosus strain

Want to check out the patent?
Despite the fact that the overall results are much more exciting than those in the previously discussed green tea study, I'd advise you to keep calm. We are after all dealing with another Nestlé study on a patented strain of Lactobacillus rhamnosus (LPR), i.e. "CGMCC1.3724" (date patented: 2012-05-10; #20120114622), and cannot tell how many never published negative study results the Nestlé guys had to dispose of, before Marina Sanchez et al. finally produced study results that pleased the marketing division of this multinational corporation.

What? Ok, ok... let's get back to the facts: The scientists from the Laval University and the Nestlé Research Center randomized a group of one-hundred fifty-three 18 to 55 year-old obese men and women to receive either a placebo or the said LPR formulation with 1·6 × 108 colony-forming units of LPR and additional oligofructose and inulin per cap for a total of 24 weeks.

In the course of the first 12 weeks (phase 1), each participant received a personalised diet plan that would have him or her consume 500 kcal/d less than he or she'd need for weight maintenance (just as an aside, that's 100kcal more than for the subjects in the green teas study). During phase 2, each participant received a personalised diet plan without energy restriction. The good thing, the resting energy expenditure (REE) was actually measured: after a 12 h overnight fast in subjects having had rested for at least 15 min in a standardised supine position. This procedure was repeated thrice: (1) At baseline, (2) after the weight-loss and (3) after the second phase weight-maintenance periods using indirect calorimetry.
Figure 2: Changes in body composition (all data in kg) in men (left, blue) and women (right, orange) after weight loss (ΔW12) and weight maintenance (ΔW24) phase (Sanchez. 2013)
The data in figure 2 confirms what the abstract says: "The intention-to-treat analysis showed that after the first 12 weeks and after 24 weeks, mean weight loss was not significantly different between the LPR and placebo groups when all the subjects were considered."

Figure 3: Changes in metabolic parameters, i.e. energy intake (kcal/day), resting energy expenditure (REE, kcal/day) and respiratory quotient (RQ, remember: low RQ = high fat, low carb oxidation) after 12 and 24 weeks (Sanchez. 2013)
It does yet also confirm - and that there was a significant treatment × sex interaction, observed with the women in the treatment group losing significantly more weight than those in the placebo group (P= 0·02). More importantly, though...
"[...w]omen in the LPR group continued to lose body weight and fat mass during the weight-maintenance period, whereas opposite changes were observed in the placebo group."
For the unlucky men, on the other hand, the (unquestionably expensive) supplement didn't do sh*t: Their "changes in body weight and fat mass during the weight-maintenance period were similar" irrespective of whether they received the placebo or the active treatment.

Whether this was the reason or a consequence of the fact that the the men didn't show similar significant reductions in circulating leptin, as the women is questionable. Based on the fact that the relative abundance of bacteria of the Lachnospiraceae family in faeces increase only in women, we do yet have to assume that the missing reduction in leptin, as well as the absence of the significant body fat reductions, the researchers observed in their female subjects was simply a results of ...
  • under-dosing - the same the 1·6 × 108 colony-forming units of LPR that was sufficient for the average woman (body weight ~89kg) could have been too low for the guys (body weight ~104.3kg) 
  • dietary interference - there could have been something in the diets of the guys that ruined the effects of the supplementation (lactobacilli are not exactly friends of meats and we all know that men love their meat ;-)
  • different baseline gut microbiome - it goes without saying that you cannot place a group of rabbits in forest full of predators and expect them to survive; similarly the LPR spores may have come off second in the guts of the men, because they have a less "LPR-friendly" baseline colinization
  • fundamental sex differences - at the moment I am not sure what the underlying reasons could be, but it's not impossible that hormonal difference could have played a role as well
I am pretty sure that I could come up with a whole host of additional, increasingly bizarre ad-hoc explanations for the null-effect Marina Sanchez and her colleagues from the Laval University and the  Nestlé Research Center in Lausanne observed in their male study but would rather conclude this news-item with the scientists own funky, but not unlikely explanation: Men are simply too good at dieting!

True: Women have a harder time losing weight even with high protein | more
As the authors point out, we know from previous trials (and corresponding SuppVersity posts, read more) that men are generally more prone to respond to a negative-energy balance intervention than women - and that's true irrespective of whether it is an exercise-training programme (Tremblay. 1984), a diet– exercise programme (Doucet. 1999), or a session of exercise and of mental work (Pérusse-Lachance. 2013). Plus, if you look at the data in figure 2, you'll see that this is actualy "concordant with the results of the present study that shows higher weight loss in men in the placebo group than in the women". Sanchez et al. do now believe that the high baseline success "abolished this difference" (Sanchez. 2013).

In view of the fact that there was a difference in a single low-abundance taxonomic group  (Prevotellaceae) between the baseline gut microbiome of the male and female study participants, I would still not exclude that the different baseline gut microbiomes could at least have added to the 'effect abolishing effect' of the sex-specific ease of weight loss in men. I mean, why wouldn't the feces of the men show an increase in lactobacillus spores, if the supplement worked?
Bottom line: Today's installment of the short news is very characteristic of the dilemma with weight loss supplements. We are just realizing that the classic thermogenic 'rodent fat burner' don't really work in humans. Against that background the rise of supplements that target the gut microbiome and exert much more complex body recompositioning effects comes in the nick of time.  Unfortunately, our understanding of the complex interactions between the gut microbiome and our immune system in the context of the emerging science of immunonometabolism is so incomplete (Mathis. 2011) that we are more or less groping in the dark, whenever we supplement subjects, patients or even ourselves with allegedly healthful bacteria.

All alleged benefits aside,  "specificity", the 2nd Principle of Sensible Supplementation, should keep you away from the next best GNC or online supplement store. The two studies at hand do after all not warrant the use of either green tea or lactobacillus supplements as weight loss aids in lean, healthy and active  men or women.
Accordingly, the observation that green tea supplements won't help sedentary over-weight women to lose weight appears to be much more reliable than the allegedly impressive weight loss effects of the probiotic during the "maintenance phase" of the Sanchez study.

We must however not forget the respective constraints of the research design and irresponsibly over-interpret the results of the EGCG study to (a) the potential benefits of regular 'whole' tea consumption in the average, non-obese individual (Wu. 2003) or (b) visceral fat loss in diet + exercise interventions in obese individuals (cf. Maki. 2009). Similarly, the fact that obese women will lose weight on a LPR supplemented maintenance diet is very unlikely going to translate to lean, athletic folks like you and me. According to the 2nd Principle of Sensible Supplementation, which is "specificity" (learn them all), I don't see you or me heading over to the next best online shop to buy LPR or EGCG supplements - irrespective of the promising results of the Sanchez trial.

References: 
  • Bantle JP, Wylie-Rosett J, Albright AL,et al.(2008) Nutrition recommendations and interventions for diabetes: a position statement of the American Diabetes Association. Diabetes Care31, Suppl. 1, S61– S78.
  • Davis NJ, Emerenini A & Wylie-Rosett J (2006) Obesity management: physician practice patterns and patient preference. Diabetes Educ32, 557 – 561. 
  • Maki, K. C., Reeves, M. S., Farmer, M., Yasunaga, K., Matsuo, N., Katsuragi, Y., ... & Cartwright, Y. (2009). Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults. The Journal of nutrition, 139(2), 264-270.
  • Mathis, D., & Shoelson, S. E. (2011). Immunometabolism: an emerging frontier. Nature Reviews Immunology, 11(2), 81-83.
  • Mielgo-Ayuso J, Barrenechea L, Alcorta P, Larrarte E, Margareto J & Labayen I (2013). Effects of dietary supplementation with epigallocatechin-3-gallate on weight loss, energy homeostasis, cardiometabolic risk factors and liver function in obese women: randomised, double-blind, placebo-controlled clinical trial. British Journal of Nutrition, available on CJO2013. 
  • Tremblay, A., Despres, J. P., Leblanc, C., & Bouchard, C. (1984). Sex dimorphism in fat loss in response to exercise-training. Journal of obesity and weight regulation.
  • Wu, C.-H., Lu, F.-H., Chang, C.-S., Chang, T.-C., Wang, R.-H. and Chang, C.-J. (2003), Relationship among Habitual Tea Consumption, Percent Body Fat, and Body Fat Distribution. Obesity Research, 11: 1088–1095.

3 comments:

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  2. hello,
    People drink green tea. But they have no idea that green tea has these specialties.
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