Yeast Hydrolysate Powered Fat Loss: 7% Reduction in Total Body Fat and 14% Reduction in Abdominal Fat - W/out Diet?

Will the fat-burning magic of 1g/day of yeast hydrolysate dissolve the fat that's still covering the last 2 packs?

It sounds like a marketing scam and I must warn you, one of the authors of a soon-to-be-published paper on the basis of which I came up with this headline is actually with a company that specializes in food additives.

This obviously warrants a heightened degree of suspicion, but it does not mean that the study results could or even must be doctored. I would thus suggest, we take a look at what the Korean scientists from Jeonju University, the University of Seoul, the Korea University and the Neo Cremar Company Ltd. actually did and found before we jump to any premature conclusions about the validity or non-validity of the data.

What exactly is yeast hydrolysate?

I guess, the first thing we have to address is what exactly it was Jung et al. administered to their 24 male and 30 female participants  with body mass indices (BMI) of at least 25 kg/m² (the obesity cut off in the Asia-Pacific region is 25 kg/m²). To this end, it's best to look at how this "supplement" was produced (if you want the short version fast forward to the first red box ;-)

1. 

   You've read about the anti-Crohn's effects of saccharomyces cerv. (bakers yeast) in the SuppVersity Facebook News, recently.

   Saccharomyces cerevisiae (IFO 2346) is incubated in a growth medium containing 2% molasses, 0.6% (NH4)2SO4, 0.1% MgSO4$7H2O, 0.2% KH2PO4, 0.03% K2HPO4,  for 3 days at 30°C.
2. After incubation, the culture is centrifuged at 10,000g for 20 minutes.
3. Immediately after the cells are removed from the centrifuge, they are suspended in 20 mM phosphate buffer (pH 7.0) and hydrolyzed with 1000 units of bromelain at 30 C for 4 h.

The result of this third step actually is already a, but not yet the hydrolysate. To achieve the "good stuff", it is then centrifuged at 10,000g for 20 min. The small molecules which are then removed from the supernatant are then passed through a 10 kDa molecular-weight cutoff membrane and eventually lyophilized - et voilà!

"Hold on! So what do I need?" Before you hit the "too complicated button" at the bottom of this page, let me briefly point out that you don't need to understand or memorize the production process. The thing you have to look for, when you are shopping for corresponding products is a yeast hydrolysate with a maximal molecular weight (that's ~ the size of the indiv. peptides) of <10kDa that was produced from Saccharomyces cerevisiae.

In the study at hand, the of this 3+1 step process was packed into 500 mg pouches before it was handed over to the subjects in the active arm of the study (the placebo contained dextrin). 

Figure 1: Inter-group baseline differences for weight + body composition for men and women (Young. 2014)

Both the placebo and yeast supplements had to be taken twice a day 30 min before breakfast and dinner. So far that all sounds like standard procedure. If you take a look at the outcome of the randomization process, you will yet see that there are non-negligible inter-group differences in body composition (see Figure 1): In conjunction with the high fat mass, the low body weight and lean mass of the ladies in the control group, could have significant effects on the change in body weight. Unfortunately, the scientists did not test the significance of this difference, but a 39% gap in lean body mass that comes hand in hand with a 13% higher fat mass can be expected to have a very relevant effect on the outcome of any dietary intervention.

Speaking of dietary interventions! there was no dietary intervention.

I know, it sounds hilarious, but there was no dietary intervention. All the participants had to do was to consume the 1g of yeast hydrolysate or the 1g of dextrin in 2x500mg servings 30 min before breakfast and dinner. That's at least what they were advised to do.

Figure 2: Changes in energy intake (% baseline) and body composition (Young. 2014)

The data in Figure 2 does yet tell you that what they actually did (voluntarily, though) was "dieting". This is particularly true for the female study participants, who reached caloric deficits of 26% by week 6-8 and 28% by week 8-10. Against that background it's not that surprising that the statistical significant changes in body comp were only observed in the female study participants.

There are no effects on resting metabolic rate! The notion that the reduced energy intake is the main, if not the only driving force of the fat loss Jung et al. observed in the study at hand is supported by observations the researchers made in a previous study from 2011 (Jung. 2011a). In the said study, the 20 obese females (body fat >28%) in the yeast group did experience a non-significantly improved fat loss compared to the control group. They did yet also suffer from a "higher" reduction in resting metabolic race (-9.69kcal/day vs. -4.35kcal/day) - similarly non-significant as the weight loss difference, obviously.

This does not mean that the yeast extract doesn't work - quite the contrary, for the average individual who is neither willing nor able to adhere to a caloric deficit without the help of tools like this, it could actually come very handy. For the average physical culturist, it would yet obviously be more interesting if yeast hydrolysates had spot reducing qualities (learn more about spot reduction). And if we take another look at the full text of the study, we could actually argue that this is basically what the authors suggest, when they refer to the results of previous studies and state:

"Yeast hydrolysate increases the reduction of body fat in obese individuals compared with placebo, which supports the hypothesized abdominal fat-lowering effects of yeast hydrolysate" (Young. 2014)

If you look at the study at hand, the question we would have to answer should thus read: Are the abdominal and total fat mass disproportionate. Or to say it differently: Did the subjects lose signifcantly more abdominal than total fat? And in view of the previously discussed problem: Did this vary between male and female participants? Unfortunately, the scientists didn't do us (or rather me) the favor of doing this for us, already. Therefore I had to do the calculations and plotting for Figure 3 myself:

Figure 3: Relative change in body fat mass and abdominal fat thickness (Jung. 2014)

As the text in the box in Figure 3 already tells you, the existing discrepancy between the reduction in total body fat and abdominal fat thickness does not necessarily "prove" the spot reducing prowess of yeast hydrolysate. We do after all know that in the chubbier folks the unhealthy fat in / on the midsection is usually the first to go.

Is the fat loss really localized? 

Furthermore, a previous study by the same researchers clearly refutes the abdominal specific fat loss effects. The corresponding paper was published in 2011 in the Journal of Food and Biochemistry (Jung. 2011a; same paper I referenced in the box above), and despite the fact that the researchers observed a trend for an increase in weight loss within only 4 weeks on the same <10kDa yeast hydrolysate, the fat loss results of the obese women who participated in the study were at best triceps (-2.15 vs. -1.05mm reduction in skinfold thickness in yeast vs. control) and not belly specific (-1.70 vs. -1.08mm reduction in skinfold thickness in yeast vs. control).

Unfortunately, I cannot tell you whether the same can be said of the 2009 paper by Suh et al., because the online archive of the Journal of Food Science and Nutrition, where it was published starts in March 2011. In view of the fact that it was not "ab-specific" in obese women, I really doubt that it will have has particularly pronounced effects on the waistline of female college students - a subject group of whom you would expect that they are at least somewhat closer to the fitness and leanness level of the average SuppVersity reader.

If you are looking for alternative, yet not necessarily more effective purported spot-reduction supp- lements / techniques, you may want to (re?)read the recent SuppVersity article about green tea, green clay & magnesium sulfate soaked "plaster body wraps" | read more

Is yeast hydrolysate an effective tool in your weight loss arsenal? A definitive answer to this question is yet still lacking. Personally, I would spend my money otherwise, because I have never had a problem with cutting back calories, when I decided that this is necessary to lose weight. If, on the other hand, you belong to those people who are constantly hungry, it may be worth trialling a once month supply of yeast hydrolysate caps (or sachets).

The only thing you should be prepared for is that it is not going to work if you don't diet. In all of the human studies I've seen so far, the weight loss went hand in hand with a reduction in calorie intake; and despite the fact that there is good evidence that the His-Pro (=Cyclo) peptides in yeast hydrolysates have additional value as potent antioxidants (Jung. 2011b), their subsequent effect on glucose metabolism will depend on a baseline increase in inflammation. In other words: The bigger your belly, gluttony and baseline inflammation, the greater the benefits.

References:

• Jung, E. Y., Kim, S. Y., Bae, S. H., Chang, U. J., Choi, J. W., & Suh, H. J. (2011a). Weight reduction effects of yeast hydrolysate below 10 kDa on obese young women. Journal of Food Biochemistry, 35(2), 337-350.
• Jung, E. Y., Lee, H. S., Choi, J. W., Ra, K. S., Kim, M. R., & Suh, H. J. (2011b). Glucose Tolerance and Antioxidant Activity of Spent Brewer's Yeast Hydrolysate with a High Content of Cyclo‐His‐Pro (CHP). Journal of food science, 76(2), C272-C278.
• Jung, E. Y., Hong, Y. H., Kim, J. H., Park, Y., Bae, S. H., Chang, U. J., & Suh, H. J. (2012). Effects of Yeast Hydrolysate on Hepatic Lipid Metabolism in High-Fat-Diet-Induced Obese Mice: Yeast Hydrolysate Suppresses Body Fat Accumulation by Attenuating Fatty Acid Synthesis. Annals of Nutrition and Metabolism, 61(2), 89-94.  
• Jung, E. Y., Cho, M. K., Hong, Y. H., Kim, J. H., Park, Y., Chang, U. J., & Suh, H. J. (2014). Yeast hydrolysate can reduce body weight and abdominal fat accumulation in obese adults. Nutrition, 30(1), 25-32.
• Suh, H. J. (2009). The weight reduction effect of yeast hydrolysate-SR101 on female college students. Journal of Food Science and Nutrition, 14(2), 123-128.

Doping 2.0 - Myostatin Blocker. We are Finally There! Orally(!) Administered Recombinant Yeast Increases Body Weight and Muscle Composition in Rodent Model.

Image 1: "Wendy" myostatin negative dog
and 7 months old baby of a 24-year old
female former athlete with a family
history of "particular" strength
(image "baby" from Schuelke. 2004)

You have seen those images of myostatin-negative bulls, mice and dogs. Those ugly overmuscled creatures, who cannot even carry the weight of their own musculature. Notwithstanding, you were fascinated by the idea that myostatin blockers, i.e. drugs that inhibit the growth and differentiation factor 8 (GDF8), would turn you into lean, mean mass-monster, but the only results you could find in reliable source were disappointing? Well, you may then get even more excited, when the reliable source your are just studying is telling you that "we are finally there"! Scientists from the Shaan’xi Key Laboratory of Molecular Biology for Agriculture at the Northwest A&amp;F University in Shaan’xi, China have found a way to selectively increase muscle weight in mice by oral administration of a whole recombinant yeast Saccharomyces cerevisiae vaccine (Zhang. 2011).

Before the yeast was administered to the mice at a weekly dose of 120,000,000 yeast cells for 5 weeks, Zhang et al. had cultured the yeast with copper sulfate for 10h to induce the expression of myostatin and ovo-myostatin proteins.

Figure 1: Increases in body weight of 5-week old Kunming mice after 5 weeks of oral or intravenous treatment with recombinant yeast cells (calculated based on data from Zhang. 2011).

As the data in figure 1 goes to show, the oral "immunization" procedure turned out to be more effective than the scientists had even hoped for. Still, vaccination by injection was 7% and 9% more growth promoting for the myostatin (MSTN) and ovo-myostatin (Ovo-MSTN) yeast, respectively.

Figure 2: Additional muscle gain measured in forelimb, hindlimb muscles, as well as triceps brachii and biceps femoris compared to control in 5-week old Kunming mice after 5 weeks of oral or intravenous treatment with recombinant myostatin or ova-myostatin yeast cells (calculated based on data from Zhang. 2011).

In view of both agricultural applications, as well as legal and illegal performance enhancement in recreational and professional athletes, the most important finding of the study yet turns out to be a null-finding: Null, that is the number of pathological change the scientists observed in the course of the study - no abnormal organ growth, muscle weakness and all the other ailments myostatin-null mice, bulls, dogs and whatever poor animals scientists have hitherto genetically modified, usually suffer from:

In  this  study, immunized mice in all groups were found generally healthy looking and  no  significant  damage  in  any  internal  organs. [If one also takes into account the report on the "myostatin baby" by Schuelke et al. (Schuelke. 2004)] these findings suggest  that  immuomodulation  of  myostatin  is  safe in  both  laboratory  animals  and  human.

Image 2: While the mice did gain significant
amounts of weight (esp. muscle) they are
completely healthy and do by no means
look as bulky as genetically modified dogs,
bulls and co. (image from Zhang. 2011).

If you look at the mice in image 2, it is in fact hard to tell, which of the mice received the control and which the myostatin yeast and that despite the fact, that - assuming similar effects in adolescent human beings - the average sleeve size of humans who have been immunized with this yeast would increase from ca. 32cm to ca. 43cm! That being said, it is unlikely that the "immunization", which has your body produce antibodies against myostatin and thus blocks the inhibitory effect of the TGF beta protein on muscle growth, will produce such profound results in adults, whose bodies obviously are not primed to growth in the way the bodies of children or adolescents are... but hey, there are enough aspiring young athletes in the Chinese Olympic Team to see preliminary results in 2012 (hoops, I think this was not 100% politically correct ;o)

Absurd: Will Supplemental Zinc Gluconate Deplete Your Zinc Levels?

Normally, I restrict myself to very recent studies, but the results of this 2007 (Tompkins. 2007) study on the bioavailability of zinc-enriched yeast and zinc gluconate in healthy volunteers that recently resurfaced on the Mind&Muscle boards, is too counter-intuitive and, if not scientifically flawed, important not to make it into the news.

In the study, which used a randomized, two-way crossover design, the volunteers were randomly assigned in groups of three to consume a single dose of either 20 mg of total Zn in the form of Zn gluconate or Zn yeast with 150 ml of water, after that urine, blood, and fecal samples were collected and analyzed over a 48-h period. The results were surprising, while "Zinc gluconate gave higher Zn concentrations in the blood in the first 6 h" it did not only show greater loss in the feces, but ...

the net Zn balance after 48 h for Zn yeast was 9.46 but for Zn gluconate it was -2.00, indicating that Zn gluconate supplementation contributed to a net loss of Zn.

As far as the reasons for this observations are concerned, the scientists speculate:

Presumably, this “extra” Zn lost was released from the body’s store of Zn metallothionein; however, we do not have any evidence of the source of the Zn material. This may suggest that the Zn salts stimulated a Zn detoxification pathway.

If this were true and the results are not biased by the background of the Institut Rosell, which is obviously financed by Lallemand Inc. who produce (pro-)biotic products (i.e. yeast based products), you might want to reconsider your own supplementation practices. The high doses of Zn Salts commonly used by bodybuilders and fitness enthusiasts (many suggest >50mg Zinc per day) may in fact lead your body to believe he becomes intoxicated with zinc. It is then a very natural reaction to excrete zinc and as the data from this study shows, this "excess" zinc (i.e. more zinc than you supplied) must - at least in parts - stem from zinc stores somewhere in your body.