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Gut health is "all the rage", lately. So even if it's true that this may be one of the most culpably neglected areas of research in the past century, we should still be careful not to hype the effect of the gut on your physique and health too much.

Well, probiotics and the human microbiome (the one in the gut and elsewhere) are all the rage, these days. Against that background, it's not really surprising that a probiotic supplement and thus a human microbiome modulator made it into the waredownloadsoft news (again). What may be surprising, though, is the fact that casein didn't just do the same, but that its appearance here in the news is not due to its muscle building prowess. Rather than that, casein made the cut, because a recent study by Francois Mariotti, et al. shows that - even in comparison to whey protein - casein attenuates the potentially unhealthy postprandial triglyceride response to a mixed high-fat meal in healthy, overweight men.

• Cheesy! Casein keeps your trigs in check - Due to the interaction between elevated postprandial triglyceride levels, insulin resistance and cardiovascular disease, the results of the previously mentioned study by Mariotti et al. (2015) may be of interest not just for all of us. After all, the proposed mechanism of which the authors, scientists from the AgroParisTech speculate that it is a direct result of the same

  "solubility of casein and its precipitation that forms a gel in the stomach [which have long been] known to influence its rate of absorption and postprandial protein metabolism in the context of regular, low-energy meals" (Mariotti. 2015),

  as the marked effect on the chylomicron kinetics and decrease in postprandial TGs, a risk factor for cardiovascular disease, the French scientists observed in the study at hand.
  

  Figure 1: Area under the curve for triglycerides (did respond), amino acids (didn't respond) and glucose (didn't respond) in 10 overweight subjects after consuming isocaloric high-energy meals with 15% of the energy from protein in form of casein (CAS), whey protein (WHE) or alpha-lactalbumin enriched whey (LAC | Mariotti. 2015)

  As you can see in Figure 1, the proteins which made up exactly 15% of the total energy content of the high-fat meal that was fed to 10 healthy overweight men with an elevated waist circumference (>94 cm) did not affect the subjects' postprandial plasma glucose, amino acids, insulin, or nonesterified fatty acid levels (which would, by the way, suggest that ingesting whey or an alpha-lactalbumin enriched whey protein with a meal ruins its amino acid absorption advantage). The study outcome that did differ, though were the postprandial triglycerides (TGs) levels, where the provision of casein lead to a highly significant 22% (+/- 10%) reduction in the 6-h area under the curve.

• As the authors point out, similar trends were shown for plasma chylomicrons [apolipoprotein (apo)B-48; P < 0.05], yet not for the postprandial oxidative stress (plasma hydroperoxides and malondialdehyde), endothelial dysfunction (salbutamol-induced changes in pulse contour analysis), or low-grade inflammation. This is also why it is as of yet only a logical, but hitherto unsupported hypothesis that consuming casein (micellar casein, not regular sodium or calcium caseinates) would also reduce one's cardiovascular disease risk. Eventually, it does yet appear to be the more reasonable adjunct to a full meal anyway - the purpose of the latter is after all to keep you satiated for a long time; and that's where casein is unquestionably a better choice than whey.
• Probiotics - 0.5% body fat reduction, and a 2.68 cm² reduction in subcutaneous fat area are not much, but they occurred in the absence of diet and exercise - If the trend continued and the 120 nondiabetic and overweight subjects Jung et al. divided into two groups: There was the probiotic group with 60 individuals who consumed 2 g of powder of two probiotic strains, L. curvatus HY7601 and L. plantarum KY1032, each at 2.5 × 109 cfu, twice a day. And there was the and a placebo group, likewise 60 individuals, who consumed the same amount of powder that did not contain any probiotics.
  

  Figure 2: Changes in body composition according to waist measurement and CT scans - All values are relative changes in waist and fat area measure from week 0 to week 12 (Jung. 2015).

  Both groups were advised to take their supplements immediately after breakfast and dinner, but only the probiotic group saw relevant improvements in body fat at slow) pace - albeit a pace at which it would take them "only" 5 years to finally make it into healthy body fat zones.

• Ok, that's painfully slow, but given the fact that the food intake of both groups didn't differ significantly, it is still noteworthy that the 2 g of probiotic powder which contained contained 0.1 g of L. curvatus HY7601, 0.1 g of L. plantarum KY1032, 1.24 g of crystalline cellulose, 0.5 g of lactose, and 0.06 g of blueberry-flavouring agent made the subjects lose significant amounts of body fat, while their peers who received 2 g of a placebo powder that contained 1.34 g of crystalline cellulose, 0.6 g of lactose, and 0.06 g of blueberry-flavouring agent kept gaining.
  

  Figure 3: The provision of the probiotic supplement did also trigger significant improvements in the above markers of cardiovascular disease risk - if it's not the small fat loss, it would thus be the potential CVD risk reduction that makes the use of probiotic supplements attractive especially for overweight individuals (Jung. 2015).

  In conjunction with the likewise statistically significant beneficial effects on health markers like LDL oxidation and LDL particle size which indicate significant improvements in cardiovascular disease risk, this is still the first non-sponsored study (the study was financed by Korean Ministry of Science) that shows that supplementing with commercially available probiotics in man may actually produce health-relevant beneficial effects.

References:

• Jung, Saem, et al. "Supplementation with two probiotic strains, Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032, reduced body adiposity and Lp-PLA 2 activity in overweight subjects." Journal of Functional Foods 19 (2015): 744-752.
• Laugesen, Murray, and R. B. Elliott. "Ischaemic heart disease, Type 1 diabetes, and cow milk A1 β-casein." (2003).
• Mariotti, François, et al. "Casein Compared with Whey Proteins Affects the Organization of Dietary Fat during Digestion and Attenuates the Postprandial Triglyceride Response to a Mixed High-Fat Meal in Healthy, Overweight Men." The Journal of nutrition (2015): jn216812.
• McLachlan, C. N. S. "β-Casein A 1, ischaemic heart disease mortality, and other illnesses." Medical Hypotheses 56.2 (2001): 262-272.

If you drink "old school" protein shakes with milk and eggs, you don't have to worry if casein or whey is better on hypercaloric diets ;-)

Creatine, whey and - at least optionally - casein are on the list of "must have" supplements for anyone who has been following a solid workout routine a decent high(er) protein diet for a year or longer. And even though this makes any news study on one of the three potentially interesting for a huge part of the waredownloadsoft readers, the results are often so unsurprising that they are hardly worth an individual waredownloadsoft article...

I mean, let's be honest: You wouldn't be excited if I wrote about study #1023 showing a practically irrelevant acute increase in protein synthesis, let alone totally meaningless increases in mTOR in response to the ingestion of whey protein, would you?

For today's installment of the short news, I will picked two studies that are at least not as simplistic (and useless) as the previously mentioned 1023rd whey protein study.
Study #1 sheds some light onto the intricate differences between the way(s) whey and casein may differently affect our energy balance, gut hormones, glucose metabolism, and taste preference (Pezeshki. 2015), while study #2 is actually a meta-analysis that makes a first attempt to actually quantify the average effect of creatine on leg strength (Lanhers. 2015).

• Whey or casein? The answer to this question probably depends on your goals - That's at least what the complex results of a similarly complex series of experiments from the Snyder Institute for Chronic Diseases at the University of Calgary appears to suggest (Pezeshki. 2015). In the corresponding study, the researchers determined the effects of dietary whey, casein, and a combination of the 2 on energy balance, hormones, glucose metabolism, and taste preference in rats.
  
  Yes, this does mean that we must not uncritically transfer the results to humans. It does not mean, however, that we cannot use the results of Pezeshki's study, at all. Much of what we know and have later proven in human studies about our metabolism has initially been observed in rodents. Doing the same experiments with humans would not just have been significantly more expensive, it would also have been thwarted by misreported energy intakes and a lack of dietary control. So, if you belong to the "it's a rodent study, so I ignore it, if the results don't fit my world-view" faction, you are free to fast forward to the Lanhers study. If not, here's the elevator pitch on the two experiments the scientists conducted:
  • The hormone / energy expenditure experiment: Obesity Prone CD (OP-CD) rats were fed a high-fat control diet (33% fat energy) for 8 wk, and then randomly assigned to 4 isocaloric dietary treatments (n = 12/group): the control treatment (CO; 14% protein energy from egg white), the whey treatment (WH; 26% whey + 14% egg white), the casein treatment (CA; 26% casein + 14% egg white), or the whey plus casein treatment (WHCA; 13% whey + 13% casein + 14% egg white) for 28 d. Measurements included food intake, energy expenditure, body composition, metabolic hormones, glucose tolerance and key tissue markers of glucose and energy metabolism.
  • The food intake / preference experiment: Naive Obesity Prone CD (OP-CD) rats (not the same rats as in experiment 1) were randomly assigned to 3 groups (n = 8/group). During an 8 d conditioning period, each group received on alternate days either the CO or WH, CO or CA, or CO or WHCA. Subsequently, preferences for the test diets were assessed on 2 consecutive days with food intake measurements at regular intervals.
  If you take a look at my compilation of the most relevant data in Figure 1, you will see significant improvements in glucose management in all groups (Figure 1 | G). You should yet also be able to see that the most significant increase in GLUT-4 expression and thus the muscles ability to take up glucose occurred in the casein and mixed protein groups. In the whey group, on the other hand, where the insulin levels were the highest the increase in GLUT4 receptor expression was negligible and the 60 minutes post value for glucose after the glucose tolerance est was higher, but not significantly higher than in either the mixed protein or casein group.
  

  Figure 1: 0-60 minute hormone, glucose, cytokine and gene response to glucose tolerance test in diet-induced obese rodents fed diets containing either low amounts of protein or high amounts from whey, casein or a combination of whey + casein (Pezeshki. 2015).

  Since you will usually hear that whey is the #1 glucose repartitioner this may seem odd. In view of the fact that insulin can only drive glucose into the cells if they actually "stretch out their glucose "suckers", i.e. the GLUT-4 receptors, it is yet only logical - and that despite the fact that we cannot (yet) explain the differential GLUT-4 response. 

• What remains to be seen, though, is whether this measurable, but not in all details statistically significant difference actually matters. If you look at the food intake and preference data in Figure 3. It would seem as if it didn't. I mean, if we apply "Taubes'ian" logic, here, the high(er insulin levels in the whey group should have made the rats overeat...
  

  Figure 2: Daily food intake during conditioning trials. Rats were fed, on alternate days, a control diet or whey (A), casein (B), or a combination of whey and casein (C). Mean hourly food intakes on 2 consecutive days of preference testing, with access to both control and one of the high protein diets (D, E, F | Pzeshki. 2015).

  ... a brief glimpse at the data in Figure 2, however, tells you that this was clearly not the case. It is thus not surprising that the final lean and fat mass percentages in Figure 3 did not differ significantly between the groups, even though some of you will notice a non-significant lean vs. fat mass advantage for the casein group. 
• Eventually, it would still appear unwarranted to use the study at hand to argue in favor of casein instead of whey protein as your protein supplement of choice. If you are yet already following my suggestion to mix the two (read even more), the results of the study at hand would be another reason to stick to that practice.
  
  Overall, we do yet have to remember that significant treatment effects in response to the increase in protein were observed in all groups. In that, it may be true that the casein group had the highest reduction in food intake (30-43% reduction) and appears to have ended up with a slightly better body composition, but hey, we are talking about non-significant differences in a study that was not just done on rodents, but on obese rodents ... and you know that the weight status obese vs. lean / athletic can make more of a difference in the way people / lab animals react to supplements than the difference between man and mouse.
• Creatine and lower limb strength - what to expect? You are probably asking yourself now: "Why on earth is Adel so interested in this meta-analysis?" Well, the answer is as simple as it is personal: The only body part of mine that appears to to have ever really benefited from creatine supplementation, strength-wise, are my legs. Accordingly, I was attracted to the Lanhers' meta-analysis, because I hoped to find some clues on why this may be the case.
  
  Now, I guess I don't give away too much, when I say that the paper didn't provide me with new insights in this respect. What the scientists' compilation and meta-analysis of the data did do, however, was to confirmation that I am not the only one whose "wheels" respond extremely favorably to creatine supplementation: One of the main results of Lanhers' meta-analysis of 60 (!) studies is after all that the effect of creatine supplementation on leg strength is not just statistically significant in almost every study they reviewed, it is also and maybe even more importantly and astonishingly independent of population characteristics, training protocols, and supplementary doses and duration (reread this - you don't have to superdose it!).
  
  In that, I find it particularly striking that even training for mostly aerobic team sports, like handball, for example, can trigger significant increases in squat performance if the players are consuming 3-5g of creatine before or after their training sessions (Note: In the corresponding study by Izquierdo, the handball players also saw significant increases in bench press performance - It's thus by no means as if creatine was a "leg strength booster", only!).
  

  Figure 4: Meta-analysis on maximal weight lifted (kg) in squat. CI confidence interval, M male, SD standard deviation, T0 baseline, T1 following supplementation (Lanhers. 2015).

  For the total workout volume (not shown in Figure 4), Lanhers et al. report almost identical effect sizes as the researchers determined them based on the absolute increase in squat performance in kg (see Figure 4); and just like the relative strength gains, the relative volume increases did not depend on the training status or age (subjects were 21-69 years old) of the subjects.
  
  In view of these results, there's really no good reason to doubt the scientists' conclusions that (a) "[c]reatine supplementation is effective in lower limb strength performance" and (b) works "for exercise with a duration of less than 3 min". If you also take into account that the average effect size for weight and volume are in the range of ~30% irrespective of the population characteristic, training protocols, and supplementary doses and duration, I hope that you can agree that there's also no reason to doubt my repeatedly voiced recommendation to "take your creatine bros" ... ah, and take it with sodium bicarbonate, obviously ;-)

• Izquierdo, M. I. K. E. L., et al. "Effects of creatine supplementation on muscle power, endurance, and sprint performance." Medicine and Science in Sports and Exercise 34.2 (2002): 332-343.
• Lanhers, Charlotte, et al. "Creatine Supplementation and Lower Limb Strength Performance: A Systematic Review and Meta-Analyses." Sports Medicine (2015): 1-10.
• Pezeshki, et al. "Dietary Whey and Casein Differentially Affect Energy Balance, Gut Hormones, Glucose Metabolism, and Taste Preference in Diet-Induced Obese Rats." The Journal of Nutrition. First published ahead of print August 26, 2015.

Whey or casein hydrolysate - or rather no protein - what to use in your intra-workout beverage for endurance?

Last week, waredownloadsoft reader Oscar Qiu asked me which protein supplements I would suggest he'd buy. My answer was simple: "Get a cheap whey protein and if you want to spend extra money, add some micellar casein. Dose it at a ratio of 20:10 whey:casein post-workout (learn why) and, if you feel you're not getting enough protein on a daily basis, optionally, take them at a ratio of 10:20 whey:casein right before bed" (learn more about pre-bed casein).

Now, I am not going to revise this basic supplementation advice I gave based on the results of a recent study from the University of the Witwatersrand (Oosthuyse. 2015), but it may still be worth considering that other protein sources like whey-hydrolysate (learn more) or, as in this case, casein-hydrolysate may have certain context-specific benefits over the aforementioned "staple proteins".
In said study, Oosthuyse et al. tried to find the "protein most suitable for ingestion during endurance exercise" (Oosthuyse . 2015). To this ends, the researchers compared the effects of co-ingesting either

• 15 g/h whey-hydrolysate with (whey-CHO) or without carbohydrates (whey-PLA) or
• 15 g/h casein-hydrolysate with (casein-CHO) or without carbohydrates (casein-PLA).

In conjunction with the placebo, only, and the carbohydrate, only, trials there are six trials, i.e. placebo, placebo+whey, placebo+casein, the 63g/h fructose: maltodextrin (0.8:1) that made up the CHO content of the test beverages, alone, and in conjunction with either whey or casein-hydrolysates.

Table 1 + 2: Dietary records (mean ± SD) for 2 days preceding the day of each experimental trial (left); composition of the experimental beverages consumed during the trials (right | Oosthuyse. 2015).

Practically speaking this meant that 2h after the last meal (postprandial), 8 male cyclists ingested either: carbohydrate-only, carbohydrate-whey-hydrolysate, carbohydrate-casein-hydrolysate or placebo-water in a crossover, double-blind design during 2 h of exercise at 60 %Wmax followed by a 16-km time trial.
Data were evaluated by magnitude-based inferential statistics and revealed only non-significant effects on carbohydrate oxidation, measured from 13CO2 breath enrichment, by either of the two protein hydrolysate in isolation (data not shown),

Figure 1: What really counts are the performance improvements (left) and potential gastrointestinal side effects during (right, c), yet not so much right after the time-trial (right, b | Oosthuyse. 2015).

This changed, when the carbohydrates came into play: While the increased carbohydrate availability obviously lead to increases in glucose oxidation in all trials, these increases were substantially decreased (98% very likely decrease) when the carbohdrate drink was co-ingested with casein-hydrolysate (mean ±SD, 242 ±44; 258±47; 277 ±33g for carbohydrate-casein, carbohydrate-whey and carbohydrate-only, respectively). As it was to be expected, this decrease in carbohydrate oxidation during exercise had to be compensated by increases in fat oxidation - in this case a 93% likely increase from 83 ±27 and 73 in the whey-carbohydrate and carbohydrate-only to 92 ±14 g in the casein-hydrolysate group.

Figure 2:  Hydro whey and hydro casein have only slightly different amino acid makeups - *indicates essential amino acids (Oosthuyse. 2015).

Now, some people who are still believing in the long-overcome theory of exercise-induced fat loss may speculate that the increased fatty oxidation in the casein group would indicate that the co-ingestion of casein-hydrolysate would increase exercise-induced fat loss. You, as a waredownloadsoft reader know that the assumption that increased intra-workout fat oxidation would equal increased fat loss is total bogus. Accordingly, you will appreciate that the addition of casein to the intra-workout equation did have additional, practically relevant benefits: It lead to a significantly faster time trial ( − 3.6%; 90 % CI: ±3.2%) performances compared to placebo-water (95 % likely benefit).

Ok, now that you've hopefully memorized that you can safely ignore the non-existent fat-loss benefits of increased fat oxidation during exercise (assuming it is just to compensate a reduced CHO oxidation, as in this case), you must be careful not to jump to the similarly unwarranted conclusion that the time-trail times in Figure 1 would indicate that you or the (endurance) athletes you may be coaching should exchange all their "Gatorades" and other CHO-based intra-workout beverages for pure casein-hydrolysates.
References:

• Bassini-Cameron, Adriana, et al. "Glutamine protects against increases in blood ammonia in football players in an exercise intensity-dependent way." British journal of sports medicine 42.4 (2008): 260-266.
• Breen, Leigh, Kevin D. Tipton, and Asker E. Jeukendrup. "No effect of carbohydrate-protein on cycling performance and indices of recovery." Med Sci Sports Exerc 42.6 (2010): 1140-1148.
• Cermak, Naomi M., et al. "Muscle metabolism during exercise with carbohydrate or protein-carbohydrate ingestion." Medicine and science in sports and exercise 41.12 (2009): 2158-2164.
• Hobson, Ruth, and Lewis James. "The addition of whey protein to a carbohydrate–electrolyte drink does not influence post-exercise rehydration." Journal of sports sciences 33.1 (2015): 77-84.
• Koopman, René, et al. "Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise." American Journal of Physiology-Endocrinology and Metabolism 287.4 (2004): E712-E720.
• Korach-Andre, Marion, et al. "Differential metabolic fate of the carbon skeleton and amino-N of [13C] alanine and [15N] alanine ingested during prolonged exercise." Journal of Applied Physiology 93.2 (2002): 499-504.
• Oosthuyse, T., M. Carstens, and A. M. Millen. "Whey or Casein Hydrolysate with Carbohydrate for Metabolism and Performance in Cycling." International journal of sports medicine (2015).
• Saunders, Michael J., Mark D. Kane, and M. Kent Todd. "Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage." MEDICINE AND SCIENCE IN SPORTS AND EXERCISE. 36.7 (2004): 1233-1238.
• Saunders, Michael J., Nicholas D. Luden, and Jeffrey E. Herrick. "Consumption of an oral carbohydrate-protein gel improves cycling endurance and prevents postexercise muscle damage." The Journal of Strength & Conditioning Research 21.3 (2007): 678-684.
• Saunders, Michael J., et al. "Carbohydrate and protein hydrolysate coingestion's improvement of late-exercise time-trial performance." International journal of sport nutrition 19.2 (2009): 136.
• Seifert, John, Joseph Harmon, and Patty DeClercq. "Protein added to a sports drink improves fluid retention." International journal of sport nutrition and exercise metabolism 16.4 (2006): 420.
• Skillen, Rebecca A., et al. "Effects of an amino acid-carbohydrate drink on exercise performance after consecutive-day exercise bouts." International journal of sport nutrition 18.5 (2008): 473.

It does not necessarily have to be supplemental micellar casein. Quark, for example, is an excellent casein source you can use in "smoothies".

As a waredownloadsoft reader you are well aware of the interactions between casein micelles and the low and high pH milieu of the intestinal tract. They clump and form a mass that is significantly harder to digest than the easily digestible albumin proteins from whey.
to assess the effects of the milk matrix on casein protein digestion and absorption kinetics and postprandial muscle protein synthesis.
The results of the experiment falsified the scientists' assumption that the addition of a milk matrix to isolated casein would result in a more rapid casein digestion and amino acid absorption, a more rapid increase in plasma amino acid availability, and subsequently greater postprandial whole-body protein accretion as well as skeletal muscle protein synthesis when compared to the ingestion of isolated casein without a milk matrix (i.e., dissolved in water).

Figure 1: Plasma tyrosine (left, top), and leucine (left bottom) concentrations (micromoles per liter), as well as protein breakdown and synthesis (right) during basal postabsorptive conditions and after ingestion of 25-g intrinsically labeled casein with or without milk serum in older men (Churchward-Venne. 2015)

If you look at the data, it is actually rather the opposite that happened: The provision of the "missing" nutrients from milk slows the digestion of casein micelles (it is possible that the total amount of protein that was absorbed is identical, but the 300 min study period does not allow for a confirmation of this hypothesis). The slower protein digestion did yet not have a negative effect on the post-prandial protein synthesis; so, there's certainly no evidence of the increase in protein anabolism Churchward-Venne et al. (2015) expected, but there's no evidence of detrimental effects, either.

Thus, if neither protein breakdown nor synthesis are influenced, the results of the study at hand suggest that another often advertised supplement "quality", i.e. maximal digestion speed, is practically irrelevant  if you get enough protein per serving.
References:

• Churchward-Venne, Tyler A., et al. "Ingestion of Casein in a Milk Matrix Modulates Dietary Protein Digestion and Absorption Kinetics but Does Not Modulate Postprandial Muscle Protein Synthesis in Older Men." The Journal of Nutrition (2015): jn213710.