Friday, September 15, 2017

IIFYM & Nutrient Deficiencies ? | (Iso-)Leucine & Glucose Uptake ↑ | Weight Lifting & Protein (RDA + 60% Required)

Missed the ISSN 14th International Society of Sports Nutrition (ISSN) Conference and Expo? I've sifted through the proceedings and picked studies of for a multi-part article series. Today: IIFYM & Nutrient Deficiencies, (Iso-)Leucine & Blood Glucose and the notorious question: How much protein do lifters need?
If you have, just like me, been unable to attend the "Fourteenth International Society of Sports Nutrition (ISSN) Conference and Expo" on June 22-24, 2017, you have missed the presentations of the following selection of studies I plugged from the proceedings. Studies like Michael Dahlinghaus' short-term (3 week) Paleo diet intervention over the course of which the subjects, the 11 healthy, normal-weight subjects who had been randomized to the intervention group lost 3.27lbs (P < .05), improved their systolic BP by 7.46 (P < .043) and boosted at least one of the fitness measures Dahlinghaus included, i.e. the number of push-ups they could do before failing (+7.36 | P < .001), significantly, while the 8 people in the control group didn't see either body weight, cardiovascular or fitness benefits.

Now, Dahlinghaus' study may be the first on the list, but it's by no means the only one that shouldn't go unrecognized, now, 2-3 months after their presentation and several months before they may eventually be published in a peer-reviewed journal (here, "may" doesn't imply that they won't be accepted; a lot of interesting studies simply aren't submitted by their often young (student) authors).
Old, but gold: studies from the 2015 proceedings of the ISSN discussed at the SuppVersity

Vitargo, Red Bull, Creatine & More | ISSN'15 #1

Pump Supps & Synephrine & X | ISSN'15 #2

High Protein, Body Comp & X | ISSN'15 #3

Keto Diet Re- search Update | ISSN'15 #4

The Misquantified Self & More | ISSN'15 #5

BCAA, Cholos-trum, Probiotics & Co | ISSN'15 #6
Here's the first serving of abstract that spiked my interest and may also be of interest for you and everyone else interested in nutrition, supplementation, and training:
  • Flexible "IIFYM" diets can be nutrient sufficient, but they don't have to be (Ismaeel 2017). That's the main message of Ahmed Ismaeel's comparison of the diets of male competitive bodybuilders which revealed (a) no significant differences between male flexible and strict dieting bodybuilders when mean nutrient intakes were compared, but (b) higher nutrients intakes and a greater proportion of individuals meeting the RDAs in the strict vs. flexibly dieting group.
    Figure 1: % off flexibly/strictly dieting bodybuilders who don't get the RDA of selected micronutrients; note: with only 30 subjects, it's not really surprising that there was no sign. inter-group difference (Ismaeel 2017).
    Individually, the differences between micronutrient intakes / the number of subjects who didn't achieve the RDA that's depicted in Figure 1 didn't reach statistical significance, though.
Warning - the studies are not yet peer-reviewed and published! Since the write-up is based on abstracts, only. I cannot discuss and scrutinize the results with the same degree of detail and healthy skepticism you're used to from other SuppVersity articles.
  • (Iso-)Leucine & glucose uptake: At least two of your BCAAs are finally good for something ☻ (Newmire 2017) -- You will remember from my four-year old article about the effects of isoleucine on GLUT-4 that there's a mechanism by which BCAAs may improve glucose uptake. Until now, it was yet not clear if that's the main or even the only effect behind previously observed improvements in glucose management in response to the co-ingestion of BCAAs with carbohydrates.

    In their latest study, Daniel E. Newmire, Eric Rivas, Sarah E. Deemer, and Victor Ben-Ezra tried to determine the independent and combined effects of isoleucine (ISO) and leucine (LEU) on incretin (GLP-1, GIP) responses and subsequently their associations with glucose (GLU), C-peptide (CP), INS, and glucagon (GCG) concentrations in healthy, inactive adults and found that "[...] ISO and LEU induced a slight glucose reduction concurrent with a counter regulatory rise in GCG" (ibid). The authors further explain that
    "[b]ecause we found no treatment effect by these amino acids on CP, INS, and GLP-1Active concentrations, this data indicates that ISO and LEU may induce glucose uptake independent of insulin and GLP-1Active responses" (Newmire 2017).
    It's not clear if these insulin independent effects were triggered by the same mechanism as the previously observed effects of isoleucine in Morato et al. in 2013.

    Figure 2: Insulin secretion of Langerhans islets incubated with amino acid; effect of leucine > isoleucine (Salehi 2012).
    It's, likewise, only speculative that the glucose-lowering effects of isoleucine, of which the study at hand shows no correlation with total GIP and insulin, are in one way or another "better" than those of leucine, which has previously been shown to (a) have non-sign. greater direct stimulatory effects on insulin secretion of Langerhans islets (Salehi 2012) an (b) exacerbate the insulin excursions in response to co-ingestion with carbohydrates and even protein (Wall 2013). Accordingly, Newmire et al. are right to state that "more rigorous investigation" is required.
Nutrient Timing? ISSN position stand -- No, this paper was not part of the proceedings of this year's ISSN conference, but it is unquestionably worth reading: The "International society of sports nutrition position stand: nutrient timing" (read it).

If you just don't have the time to read the free full text, try Alan Aragon's tabular overview/interpretation of the most important results on the left.
  • Meta-analysis of 17 subgroups from nine studies says you need >1.35 g protein/kg body weight/day to optimize muscle anabolism (Popovich 2017) -- Recently, there have been several studies seeking to quantify the "optimal" protein intake for muscle gains in strength-trained individuals. Greg E Popovich's recent meta-analysis of nine studies that assessed their subjects nitrogen balance is thus a timely review of both, older and novel evidence on the topic. Popovich aimed to
    "[...] statistically analyze previously published nitrogen balance studies to find the model that best describes the relationship between protein intake and nitrogen retention, as well as to elucidate significant variable(s) affecting nitrogen retention" (Popovich 2017).
    As previously highlighted, Popovich found nine studies with at a total of 17 subgroups for his analysis, which included testing nitrogen retention for correlations against 10 independent variables (protein intake, energy intake, energy balance, average reported daily strength-training duration, lean body mass) using multiple models.

    Figure 3: Just in case you forgot what the net protein balance is, and why it is important when we're talking about 'gains or no gains', I suggest you (re-)read my 2015 article about "Net Protein Retention and Dietary Protein" | read it!
    Popovich's linear regression model revealed positive correlations between daily nitrogen intake and nitrogen retention (r = .510) which approached significance (p ≤ .06). When normalized for body weight, the correlation became (a) more pronounced (r = .698) and (b) statistically highly significant (p ≤ .006)

    What may be the most important result of the study is that the RDA of 0.8g/kg body weight is only ~60% of the amount of protein you need to keep the status quo (0-balance).

    When Popovich writes that "the data suggest that resistance-trained persons consume greater than 1.35 g protein/kg body weight/day to optimize muscle anabolism" (ibid.) the emphasis should be on greater - after all, 1.35g/kg is enough only to maintain the status quo of resistance trainees.
In previous articles, I discussed that increase glucose uptake. This effect could be stimulated by leucine, isoleucine or the combination of all amino acids, such as the cocktail of leucine, isoleucine, valine, threonine and lysine in Salehi 2012 (Figure 2).
You want only the elevator pitches? Firstly, there's Ismaeel's study, which teaches us two things: bodybuilders who follow a flexible IIFYM diet, (a) consume an almost identical amount of macronutrients as their stricter peers but are non-significantly more likely not to meet their micronutrient demands. What? Oh, yes it's also worth mentioning that even the strict dieters didn't meet the RDA for a hell low of micronutrients (see Figure 1).

Secondly, there's the study by Newmire et al., which confirms (a) the previously discussed beneficial effects of isoleucine on glucose management and (b) the general improvements in glucose uptake in response to both isoleucine and leucine. It does yet also reinforce the question if isoleucine is a significantly better, since non-insulin / GIP dependent enhancer of glucose uptake than leucine.

Thirdly, there's Popovich's recent analysis of data of the link between protein intake and net protein balance in weight training individuals that confirms two things: (a) there's still way too little data to make definite statements about the existence of something like a saturation effect, and (b) the RDA of 0.8g protein per kg body weight is way below the 1.35g protein per kg body weight, Popovich calculated as the minimum to achieve net protein balance and thus preserve muscle mass (in that, I assume that the net protein breakdown with <1.35g/kg would come from muscle protein - at least in parts) | Comment on Facebook!
References:
  • Salehi, Albert, et al. "The insulinogenic effect of whey protein is partially mediated by a direct effect of amino acids and GIP on β-cells." Nutrition & metabolism 9.1 (2012): 48.
  • Wall, Benjamin T., et al. "Leucine co-ingestion improves post-prandial muscle protein accretion in elderly men." Clinical nutrition 32.3 (2013): 412-419.
  • You can find all abstracts this article is based on in the "Proceedings of the Fourteenth International Society of Sports Nutrition (ISSN) Conference and Expo" | read them