Sunday, March 11, 2018

5 Take-Home Messages From the Latest Nutrition Science | Plus: Things You Should but May not Know About Nutrition

Simplified overview of whole body oral protein utilization at rest. Of the protein ingested, approximately 50% is extracted by splanchnic tissues before entering peripheral circulation. Interestingly, only ~10% of the ingested protein is utilized for skeletal muscle protein synthesis while the rest is catabolized... the full-text isn't just worth reading, it is also free to read, so what are you waiting for?  Just click here and start reading!
If a scientific magazine is called "Nutrients"  and features a paper with the title "Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training" as a cover story, that will attract nutrition/fitness nerds like you and me.

The paper presents an excellent overview of the human protein metabolism and it would, in my humble opinion, be a disgrace to reduce the review to its already well-known take-home messages like 'have at least 20g of high EAA protein per meal'. So what? Well, just read the Free FT of Stokes' paper yourself.

Now, this doesn't mean that the papers I will discuss below are "worse" - in fact, some of them present more surprising results and similarly unexpected take-home messages.
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  • Adding fats and carbs to your (whey) protein shake won't make it more satiating - So don't do it, unless you need the extra calories (Giezenaar 2018)! In their latest paper, Giezenaar tested if the common practice of "making that shake more satiating" by adding "slow digesting fats" and "energy delivering carbs" doesn't work out.
    Figure 1: Left: mean (±standard error of the mean (SEM)) energy intake at the buffet meal (kcal) in healthy older men (n = 13) after drinks (~450 mL; energy content of the drink as the striped part of each bar); right: mean (±SEM) suppression of energy intake after caloric drinks compared to control (Gieuzenaar 2018).
    As you can see in Figure 1, the mix of 70 g protein, 28 g carbohydrate, 12.4 g fat even increased the total energy intake over what the subjects in the protein only and high carb shake ate at the buffet meal they were supposed to eat 2h after consuming one of the three shakes (180–210 min).

    Now, the question is: If it doesn't increase your satiety (none of the measured satiety hormones/peptides) was affected by replacing protein with carbs or adding fat and carbs (obviously, insulin increased, though), what about the "whey-to-casein-with-fat-hypothesis?In other words: If it doesn't kill your appetite, will the fat in the 504kcal monster shake at least slow whey down to casein levels?
    Figure 2: Yes, the addition of carbs and fats did slow down gastric emptying, but this only suggests and won't prove that the remnant still contains all the whey, so that the overall increase in amino acids will be slowed down compred to the (i) 70 g whey protein (280 kcal; ‘P280’; when some of the protei is replaced with carbs, as in (ii) 14 g protein, 28 g carbohydrate, 12.4 g fat (280 kcal; ‘M280’); or pumped up to  (iii) 70 g protein, 28 g carbohydrate, 12.4 g fat (504 kcal; ‘M504’ | Giezenaar 2018).
    Well, based on the study at hand, this question cannot be reliably answered, because the scientists measured only the gastric retention, not the (in this context) more relevant amino acid concentration (over time) in the blood. While the former suggests that the whey was slowed down, we cannot exclude that what the tummy retained was only carbs + fats...

    If you want to justify putting fat into your whey protein shake, try arguing based on this study: "40+% Increase in Protein Synthesis W/ Whole Egg vs. Egg Whites (Both 18g Protein) PWO"
    Unlikely, but possible. In the absence of studies measuring the time-course of aminoacidemia (amino acid concentration in the blood) after whey and whey + fat, you will still be better off trying to explain the extra fat in your shake by being bulking and "needing the extra calories" Moreover, the recently discussed whole egg study that seems to suggest that there was something anabolic about protein + fat (at least from eggs when compared to egg whites)

    Especially when you're dieting and trying to use the shake as a means to keep your cravings under control, you'd be much better off using straight micellar casein.
Beware of "fake casein": Did you know that the "casein" you've been buying may well be as fast-digesting as your whey protein? If you think that you're in the safe zone because you didn't buy casein hydrolysate, you may well be wrong. How's that? What you bought may well be the cheap(er) sodium- or calcium-caseinate, which lacks - as the name implies - the micellar structure of "real casein", i.e. micellar casein. So, you better scrutinize the label of a future purchase. If it doesn't say "micellar casein" or, even better, "100% micellar casein", buy another product.
  • Carbing up in the evening (even after workouts) won't make you fat, but it significantly reduces the increase in insulin sensitivity and glucose handling on the 'morning after' (Taylor 2018) - Actually, the RCT Harry L. Taylor conducted doesn't prove anything common sense couldn't have told us anyway. Still, the confirmation of the negative effects of carbing up in the PM after workouts (i.e. replenishing muscle and liver glycogen) on the increase in insulin sensitivity and improvements in glucose handling you see after an overnight fast in healthy individuals is important...
    Figure 3: Overview of study design and results from the original paper by Taylor et al..
    also because it confirms that the AM increase in insulin sensitivity is (at least partly) a function of reduced glycogen stores - if you replete those right after your workout, this benefit is lost and you end up similarly insulin sensitive/resistant as you'd be in the postprandial period after a glycogen repleting meal.

    Figure 4: A 2016 article I wrote addresses the performance /adaptational effects of "sleeping low" | read it.
    Speaking of glycogen: You do remember that going to be bed glycogen depleted can have other benefits, no? I wrote about those back in 2016, when a paper by Marquet et al. showed quite impressively hat carbohy-drate timing or, more specifi-cally limiting your post-training pre-bed carbohydrate intake to make sure you "sleep low" can trigger poten-tially game-changing (endu-rance) performance gains in only 3 weeks. 
There may be benefits to drinking these two + another two cups of coffee w/ lots of sugar after your workout - if you are an athlete, at least.
If you do AM/PM training and/or compete on subsequent days, the "sleep-low" strategy may still not be optimal. Rather than that, you will want to replete your glycogen stores with a 2:1 glucose:fructose mix after your workouts... why's that? Find the answer in this SV Classic from 2013 and understand how and why washing the sugar down with coffee to further enhance muscle glycogen repletion based on this 2015 article of mine.

In the greater scheme of things, this is yet just another example of the old adage that "one size doesn't fit them all". If your "size" is "sleeping low" is highly individual and may well depend on where you are in the season.
  • More evidence that protein powders may help, but are by no means necessary to make muscle gains (van Vliet 2018) - That's what a review by van Vliet et al. aimed to "evaluate the efficacy of the ingestion of nutrient-rich and protein-dense whole foods to support post-exercise muscle protein remodeling and recovery with pertinence towards physically active people" (ibid.).
    Table 1 & 2: Amount of natural protein sources require to hit the 20g protein threshold (left) and nutrient density of selected whole and processed foods (right | van Vliet 2018).
    While I do suggest that you read the FT of the review, yourself, I think it's worth to give you a sneak peak on Table 1 & 2, which list food sources of those 20 grams of protein and the corresponding nutrient contents. How's that? Well, it doesn't just tell you something about the most nutrient dense quality protein source (which is obviously milk, and - not shown - dairy products, in general), it also highlights that almost all of the red boxes (=not a source or not a good source of this nutrient) can be found on the more processed side of things.

    And it is, as van Vliet et al. point out, not just the higher nutrient density, but also the potential for increases in protein synthesis that make a difference between whole and highly processed foods as they have been observed for egg whites vs. yolks in the previously referenced study by Vliet et al. (2017) and Elliot et al. (2006) for skim vs. whole milk.
There's still a time and place for protein supplements! While you have read about the adequacy of dietary protein for the purpose of building muscle at the SuppVersity before, this does not mean that you cannot use whey (or other protein concentrates/isolates) to your advantage.

What's more muscle ana & fat catabolic - dietary or supplemental protein sources? In young people, both work equally well, the study I discussed in this #SVClassic suggests!
If you asked me for the TOP3 reasons why protein powders, and, most specifically, whey, are still worth buying this'd be my answer: (a) adequately high leucine content even w/ "low" protein intakes (e.g. 20g/meal | esp. important for older people), (b) convenience, (c) no or limited extra-calories so that you can up your protein intake w/out a significant effect on fat, and carbohydrate intake.

So, don't get confused by the last "take-home message" - It says: You can build muscle w/out protein supplements; and nutrient-wise that may even have significant advantages compared to the (let's face it) hyper-processed protein concentrates, isolates, or hydrolysates. It doesn't say that you shouldn't use protein supps at all.
  • Figure 5: Forest plot of the temporal effect sizes (ESs) of the whey protein supplement for the recovery of muscle function following resistance training, compared to a control treatment (Elliot 2018)
    Don't think of whey protein exclusively as a muscle builder! Meta-analysis shows: It's also a muscle rebuilder/recovery enhance (Davies 2018) - With an effects size ranging from 0.4 to 0.7 the effects the scientists observed from < 24 to 96 h may be of only small or medium size, but their accumulation over time may still contribute significantly to the well-established size & performance increases that have been repeatedly observed in longitudinal whey protein studies.

    In that I have to agree that a meta-analysis of "only" 13 studies will only "principally support" (ibid.) the usefulness of whey protein supplements, but with the rest of the research providing a lot of reference points with respect to the underlying mechanism (protein synthesis, increases in glutathione, functional peptides, etc.), "further comprehensive research in this area" is warranted, but there's no good reason to assume they would refute the data in Figure 5, which is generally positive - with one exception, the study by Buckley et al. that found that whey hydrolysate did, while whey isolate didn't ameliorate the reduction in peak torque - an interesting observation that should be followed up in future comparisons between types of whey. 
Your multi probably contains too little of the macro-minerals: If you are on the standard Western or a very restrictive (both food- and energy-wise), the COSMOS study (see discussion below) shows that your diet can still be deficient in both calcium and magnesium, even if you take your "multi" religiously. Why's that? Well, check out the amount of magnesium or calcium you'll find in the average product. For several (some of them good) reasons such as potential interference w/ other nutrients, both are usually dosed relatively low in MVMS.
  • First results of ongoing study highlights: Our diets aren't just low in vitamin D and magnesium. Especially for 'average Joes' taking a sensibly dosed (not mega-dosed) multi-vitamin and -mineral supplement (MVMS) may well make sense (Blumberg 2018) - The early results of the ongoing COcoa Supplement and Multivitamin Outcomes Study (COSMOS) are, as Blumberg et al. point out providing evidence that the evidence from observational studies and large-scale, randomized, controlled trials which suggest that MVMS "may reduce the risk of some forms of cancer and, potentially, cardiovascular disease" (ibid.) may be explained by a reduction of nutrient deficiencies.
    Figure 6: Proportion of subjects ≥19 years of age achieving an intake of shortfall nutrients below the EAR from food + MVMS by frequency of intake (Blumberg 2018).
    As the data in Figure 6 tells you, these vitamin shortages that occur even in people who take MVMS, but fail to take them regularly, are not restricted to the usual suspects like vitamin D and magnesium, but include vitamins, such as vitamin E or vitamin A, which are often overlooked (esp. in the health and fitness community) when we're talking about not meeting the Estimated Average Requirement (EAR)... in all that, we shouldn't forget, though, that the EARs must still be considered very rough estimates - or educated guesses if you will.
Educate yourself on "Nutrient/Meal Timing" - Learn More About it in This #SVClassic Featuring a Dozen Examples of Its Purported Impact on 'Ur Health, Weight Management & Body Composition | more
What else is worth talkin' about? Well, there's more on the health benefits of coffee, with Lafranconi et al. (2018) reporting in their meta-analysis that the "consumption of four cups of coffee per day was associated with a 10% relative reduction in postmenopausal cancer risk" (ibid.) And if you are trying to wean yourself off of coffee, you may enjoy the nootropic effects of the combination of 3 mg of astaxanthin (A) and 5 mg of sesamin (S). This combination has recently been shown to "promote recovery from mental fatigue which is experienced by many healthy people" (Imai 2018). Two things make this RCT worth mentioning (a) it's a two-way crossover study, (b) the amounts of astaxanthin and sesamin are moderate, and (c) the study didn't just measure subjective improvements in a double-blind scenario, it also revealed that plasma phosphatidylcholine hydroperoxide (PCOOH), a marker of CNS stress declined significantly in response to four weeks of A+S supplementation | Comment!
  • Blumberg, J.B.; Bailey, R.L.; Sesso, H.D.; Ulrich, C.M. The Evolving Role of Multivitamin/Multimineral Supplement Use among Adults in the Age of Personalized Nutrition. Nutrients 2018, 10, 248.
  • Buckley, J.D.; Thompson, R.L.; Coates, A.M.; Howe, P.R.; DeNichilo, M.O.; Rowney, M.K. Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. J. Sci. Med. Sport. 2010, 13, 178–181.
  • Davies, R.W.; Carson, B.P.; Jakeman, P.M. The Effect of Whey Protein Supplementation on the Temporal Recovery of Muscle Function Following Resistance Training: A Systematic Review and Meta-Analysis. Nutrients 2018, 10, 221.
  • Elliot, Tabatha A., et al. Milk ingestion stimulates net muscle protein synthesis following resistance exercise. Medicine & Science in Sports & Exercise 38.4 2006: 667-674.
  • Giezenaar, C.; van der Burgh, Y.; Lange, K.; Hatzinikolas, S.; Hausken, T.; Jones, K.L.; Horowitz, M.; Chapman, I.; Soenen, S. Effects of Substitution, and Adding of Carbohydrate and Fat to Whey-Protein on Energy Intake, Appetite, Gastric Emptying, Glucose, Insulin, Ghrelin, CCK and GLP-1 in Healthy Older Men—A Randomized Controlled Trial. Nutrients 2018, 10, 113.
  • Imai, A.; Oda, Y.; Ito, N.; Seki, S.; Nakagawa, K.; Miyazawa, T.; Ueda, F. Effects of Dietary Supplementation of Astaxanthin and Sesamin on Daily Fatigue: A Randomized, Double-Blind, Placebo-Controlled, Two-Way Crossover Study. Nutrients 2018, 10, 281.
  • Lafranconi, A.; Micek, A.; De Paoli, P.; Bimonte, S.; Rossi, P.; Quagliariello, V.; Berretta, M. Coffee Intake Decreases Risk of Postmenopausal Breast Cancer: A Dose-Response Meta-Analysis on Prospective Cohort Studies. Nutrients 2018, 10, 112.
  • Marquet, et al. Enhanced Endurance Performance by Periodization of CHO Intake: “Sleep Low” Strategy. Medicine & Science in Sports & Exercise (2015): Publish Ahead of Print.
  • Stokes, T.; Hector, A.J.; Morton, R.W.; McGlory, C.; Phillips, S.M. Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients 2018, 10, 180.
  • Taylor, H.L.; Wu, C.-L.; Chen, Y.-C.; Wang, P.-G.; Gonzalez, J.T.; Betts, J.A. Post-Exercise Carbohydrate-Energy Replacement Attenuates Insulin Sensitivity and Glucose Tolerance the Following Morning in Healthy Adults. Nutrients 2018, 10, 123.
  • van Vliet, S.; Beals, J.W.; Martinez, I.G.; Skinner, S.K.; Burd, N.A. Achieving Optimal Post-Exercise Muscle Protein Remodeling in Physically Active Adults through Whole Food Consumption. Nutrients 2018, 10, 224.