Tuesday, September 1, 2015

Kids' Low GL Breakfast Boosts Cognitive Performance 24h Later | Maternal Low Protein Diet Programs High Myostatin, Low Muscularity | Beef Beats Pickled, Not Baked Herring

We all know this is not a healthy breakfast. What we don't or rather didn't know, though, is that you have to test on two consecutive days to find out how unhealthy it actually is for your kids' brains. With Young's study we learned that.
In what? That's probably what you are asking yourself now that you've read that beef beats pickled, but not baked herring, right? Well the answer to this question can be found in my brief summary of the results of Svelander's recent meal-response study. It's, as you may have guessed, the insulin response that sucks for pickled herring. What sucks even more, though, are mothers who are afraid of protein. After all, Liu's latest study shows that they may be setting their kids up to a life as skinny fatness.

When I come to think about it, this may yet be better than giving your kids a high glycemic load breakfast to take to school. After all, Young's latest study shows quite impressively what previous studies may have missed. The ill effects of high GL breakfasts on cognition are neither immediate, nor restricted to the late AM. No, they rather last for 24h+ and maybe even longer.
Learn more about fasting and eating / skipping breakfast at the SuppVersity

Breakfast and Circadian Rhythm

Does Meal Timing Matter?

Breaking the Breakfast Habit

Fasting, Cardio & the Brain

Does the Break- Fast-Myth Break?

Breakfast? (Un?) Biased Review
  • Maternal low-protein diet affects myostatin signaling and protein synthesis in offspring's skeletal muscle - Ok, we are talking about swine, but (a) many human beings behave much worse than swine and (b) swine are actually a much better model of human metabolism than rodents and many primates (the real reason they are not the standard model is that they are too large and too long-lived, which means they need too much space, the studies last too long and get much too expensive).

    It is thus more than likely that a very similar effect on myostatin and protein synthesis as it was observed by Liu et al. in their latest study in the European Journal of Nutrition where the swine who were fed a protein-deficient diet with only 6% of the energy from protein gave birth to piglets with (a) significantly reduced body weight, (b) significantly reduced muscle weight, (c) extremely reduced relative muscle weight (to body weight) and (d) small muscle with miniscule intramuscular domains.
    Figure 1: Body weight, muscle weight (LD), myofiber cross sectional are and rel. muscle weight (LD/BW) of piglets born to sows on protein sufficient (12% | SP) and deficient (6% | LP) diets (Liu. 2015).
    While you can see all of that in Figure 1, the reasons for the lack of muscularity can be seen in Figure 2 which tells you that the piglets that were born to mothers on the low protein (LP) diet had significantly increased myostatin (remember myostatin blocks protein synthesis) and accordingly reduced S6K levels.

    With the former being the controller and the latter being the executor of protein synthesis, the results of Liu's study leave little room for speculation: A diet that contains only 6% protein - for humans ~20-30g (depending on your baseline intake) - may increase your offspring's risk of becoming under-muscled and skinny fat... what? No, I didn't say "beware vegans" - that was you!
  • Herring (pickled & baked) vs. beef, round one - fight! When it comes to the postprandial lipid and insulin responses among healthy, overweight men, the baked herring is said to be the #1 "health choice" - and here's why.

    In the corresponding study, scientists from the Chalmers University of Technology, and the Gothenburg University had seventeen healthy, overweight men (mean age 58 years, BMI 26.4–29.5 kg/m2) consume standardized lunches together with 150g of baked herring, pickled herring or baked, minced beef on three occasions in a crossover design. Blood samples were taken just before and up to 7 h after the meal. The postprandial response was measured as serum concentrations of triglycerides (TG), total cholesterol and lipoproteins (LDL, HDL and VLDL), insulin, 25-OH vitamin D (which did not change, by the way) and plasma fatty acid composition.
    Figure 2: Insulin response of eventeen healthy, overweight men (mean age 58 years, BMI 26.4–29.5 kg/m2) to std. lunches w/ baked or pickled herring, or baked, minced beef (Svelander. 2015). 
    In contrast to the pickled version, where the added sugar messed with the insulin and insulin response (the latter is not shown in Figure 2), both, the baked herring and the baked, minced meat did quite well. Differences in the cholesterol response as you'd expect them did not exist. There was however a small, albeit allegedly statistically significant advantage for the fish(es) in terms of the triglyceride response, which was lower than in the minced beef trial.

    Whether that's actually due to the extra omega-3s and whether it is even half as health-relevant as the scientists conclusions that their result "supports previous studies on the beneficial effects of herring on cardiovascular health" (Svelander. 2015) is yet highly questionable, if you asked me.
  • Isomaltulose effectively reduced the GL of kids breakfasts and has beneficial effect on their cognitive performance in the late AM and on a 2nd day! If you are following the SuppVersity news on Facebook, you will know that although previous research has associated the glycaemic load (GL) of a meal with cognitive functioning, typically the macro-nutrient composition of the meals has differed, raising a question as to whether the response was to GL or to the energy, nutrients or particular foods consumed.

    With the latest study from the University of Wales Swansea, this different. The study that was conducted by Hayley Young, and David Benton contrasted two breakfasts that offered identical levels of energy and macro-nutrients, although they differed in GL, i.e. the insulinogenic effect of the (otherwise identical) carbohydrate content
    "Using a repeated-measures, double-blind design, 75 children aged 5–11 years, from socially deprived backgrounds, attended a school breakfast club and on two occasions, at least a week apart, they consumed a meal sweetened with either isomaltulose (Palatinose™) (GL 31.6) or glucose (GL 59.8). Immediate and delayed verbal memory, spatial memory, sustained attention, reaction times, speed of information processing and mood were assessed 1 and 3 h after eating" (Young. 2015).
    Now, what is interesting and quite revealing with respect to the mixed results of previous investigations is that the nature of the meals did not influence any measure of cognition or mood after an hour; however, after 3 h, children’s memory and mood improved after the lower-GL breakfast.
    Figure 3: Kids who consumed the low GL meal with isomaltulose vs. glucose on day one had sign. improved information processing (left) and spatial memory (right) on day two (Young. 2015).
    What is even more striking, though, is the second-day effect on the speed at which the kids processed information faster and their spatial memory, which improved significantly when on the day after the kids had consumed the low GL meal. This observation is total news and it clearly suggest that the benefits of low GL meals on cognition are not necessarily acute, but may rather be accumulating.

    Overall, the kids were thus able to process information faster and had better spatial memory later in the morning, when they had the low glycemic load (GL) breakfast that was prepared with isomaltulose vs. glucose. The reason why you need any form of "sugar" (isomaltulose is still a sugar) in your kids' breakfast is still beyond me, though.
Is myostatin relevant for mass monsters only, or for normal trainees, as well? You can find the answer to this smart and justifiable question in this SV Classic Article: "More Evidence That Myostatin is an Important Inhibitor of Diet and Exercise Induced Muscle Gains in You & Me" | read more
Bottom line: If I had to pick only one study, I'd pick the Young study as my highlight of this brief nutrition science review and I'd say that it should be obvious why. I mean, come on: Who would have expected that eating a low glycemic load breakfast would yield significant cognitive benefits on the day after you consumed it even if your "day two"-breakfast does not have a low glycemic load?

For me, this is even more exciting than the sad revelation that low protein diets trigger epigenetic changes that are associated with significant increases in myostatin, subsequent decreases in protein synthesis and a significantly reduced muscle weight ... I can thus only hope that no pregnant woman actually believes that eating less than 10% protein would be good for her own health or the health of her unborn child | Comment on Facebook!
  • Liu, Xiujuan, et al. "Maternal low-protein diet affects myostatin signaling and protein synthesis in skeletal muscle of offspring piglets at weaning stage." European journal of nutrition (2014): 1-9.
  • Svelander, Cecilia, et al. "Postprandial lipid and insulin responses among healthy, overweight men to mixed meals served with baked herring, pickled herring or baked, minced beef." European journal of nutrition (2014): 1-14.
  • Young, Hayley, and David Benton. "The effect of using isomaltulose (Palatinose™) to modulate the glycaemic properties of breakfast on the cognitive performance of children." European journal of nutrition (2014): 1-8.