Saturday, March 2, 2013

BPA & Phtalate News for the Plasti-Nation. The Endocrine Contribution to Muscle Growth. Magnesium & Testosterone Increase in Parallel. Anabolic Vibes on the Lat Pull & More

You still have a couple of milli- or centimeter too much on your waistline? Let's hope this spring will provide ample time to work out in the sun, after all that's the energizing way to work out, something even virtual reality indoor exercise cannot compete with (Plante. 2006)
The SuppVersity figure of the week is "90". That was the average total amount of sunshine hours we got here in North-Rhine-Westphalia within the winter months (DWD. 2013; and there were places with only 40h!). A pretty depressing figure, in the literal sense. If you listened to the last installment of the Science Round Up (click here to download the podcast), you may remember that I was actually somewhat surprised to hear that this was the darkest Winter ever since the sunshine hours have been recorded - after all, I got my 45min of "artificial sunshine" in, every morning. So, just in case you are still wondering how it's possible to write a blogpost everyday, the data from a 2012 series of studies in Dutch schools would support that it's all about the right lighting (Sleeges. 2012).

Apropos news, here is your weekly serving of short news on all sorts of things... you are missing the exercise related news? Well, I saved those for a round-up and one or two individual posts in the course of the next week ;-)
  • Fiber renders mammalian guts colon proof (Nagy-Szakal. 2013) -- As a recent rodent study from the Baylor University suggest, it can hardly be too early to keep an eye on fiber intake. The mice in the pertinent study that had been randomly assigned to a low-cellulose (indigestible fiber that's present in fruits, veggies, whole grains etc.) diet had little to no protection against experimentally induced cholitis.

    Semisynthetic non-fermentable viscous fiber Hydroxpropyl-Methylcellulose is imported pound-wise from China and ends up as E464 from in all sorts of food - obviously at too low dosages to do the anti-obesity trick, though (learn more).
    Murine pediatric cellulose supplementation, on other hand, induces transient trophic and  anticolitic effects, which is - and that's important (!) - dependent on a continuous supply of adequate amounts of dietary fiber. The same goes for the benefifical changes in the diversity of the gut microbiome which did largely  decline after only 10 days.

    The protective effect on the epithelial cell lining and the increase in surface area in response to cellulose supplementation should also facilitate the uptake of those vitally important nutrients, people with Crohn's etc. are lacking - a result that may well be significant for those of you who are trying to make the most of the nutrients and not just the energy in their diets.

    Edit: As George Henderson rightly said, the study at hand does not talk about cancer protection, I simply inferred that from previous human studies such as Mendez (2007), Terry (2001) or Roth (2001), without mentioning that, my mistake, sorry for that. I still changed the headline to reflect the contents of the study and want to point out that George also makes a valid point stating that (a) fiber often replaces other less healthy nutrients in the diet and (b) that (my addition) "once the baby has been thrown out with the bathtub" and you already have Crohn's and co different rules may apply.
  • The diabesity syndrome - Is it the soda, or the bottle it's packaged in? (Indumathi. 2013) I am well aware that the doses of BPA we are supposed to get from our "diets" is way below those that are uses in rodent studies like the one by Indumathi et al., but don't you think that it is still remarkable that the same plastic poison aka BPA that leaches so readily into the acidic brown soup 50% of the US citizens guzzle on a daily basis, induces exactly the same nasty reductions in insulin receptor and GLUT-4 transporter expression, as well as glucose oxidation and the phosphorylation of Akt which are currently still ascribed exclusively to the soda itself (see figure 1).
    Figure 2: Effects of 20 or 200mg/kg body weight of BPA on insulin receptor and Akt phosphorylation, GLUT-4 expression in skeletal muscle and systemic insulin and testosterone levels (Indumathi. 2013)
    Now what's worst is that these pathological changes are not likely to be observed, because it happens "silently"; i.e. in the absence of elevated blood glucose levels.
    Did you know that the amount of BPA that leaches from plastics increases by x40, when you dishwash and reuse them (Brede. 2003)? And worst of all, these figures were observed in baby bottles and thus objects those of us get in contact for whom the otherwise probably harmless exposure could actually be dangerous (DiVall. 2013). Exposure to higher temperatures of liquids in plastic containers in the summer (>40°C) is another factor which contributes to an increased leakage of BPA from the container into the liquid (Makris.2013)
    With the latter being the only blood parameters that are evaluated on a regular basis within at least a reasonably large cross section of the population it's no wonder that many of us don't see how the diabetic beast and the BPA castrator are sneaking up on them before it's already too late. Obviously no reason for the FDA or any other governmental body to even bother. Aside from the U.S. Environmental Protection Agency which has published a reference dose of 0.05 mg/kg/day for BPA in 1993 (IRIS. 1993) an official acceptable daily reference intake for BPA is still lacking. Even if the current research does not suggest that our daily exposure is high enough to actually do any harm, I would expect the reference levels to reflect that - what about you?
  • In 1998 the Consumer Union wrote a letter to the FDA compaining about "endocrine disrupting chemicals" in cheese and dairy in plastics wrappings. I wonder if they knew about the masked phtalates in hygiene products, as well.
    More news for the"Plasti-Nations" (various): A couple of days ago Wu et el. published a paper on the TSH and estrogen suppressive effects of phtalates in Taiwanese children. With >40% lower TSH levels and estrogen levels the changes, in the 4-5 year olds with the highest (500ppm) phtalate exposure from food stuff is alarming. The only good news is that it these changes appear to be reversible, when further exposure is avoided (Wu.2013).

    Apropos good news, in December 2012, Fierens et al. investigated the effects of cooking at home on the phtalate content of foods and found that, except for veggies, the phtalate content of almost all foods decline after cooking (Fierens. 2012). I guess, I don't have to mention that this is not going to happen in a crock pot unless you pour away the brew.

    What you should also keep in mind is that your diet is by far not the only way you are exposed to phtalates, as a group of scientists working at a University right around my corner elucidated (Koch. 2013). The "pro-breast cancer" monoethyl carboxylpentyl phthalates (MEPs) for example usually come from personal hygiene products (it's the stuff thats called "fragrance"). The dosage, by the way, was high enough for the scientists to be able to actually measure rises in MEP concentrations after people (esp. men, by the way) took a shower. Ah, and not to forget a non-negligible amount of the low molecular weight phtalates is simply with ubiquitous sources including dust and indoor air. Up to now convincing evidence for the role of this constant assault in any of the ailments our society is suffering from is not conclusive.
  • Don't like oats? Buckwheat has similar benefits (Stringer. 2013) -- In a recently published paper in the scientific journal Metabolism, a group of researchers from the University of Manitoba in Winnipeg, Canada, reports that the consumption of buckwheat cracker either instead of rice crackers or simply on their own could help both diabetics and non-diabetics maintain a healthy weight.

    4x more iron, 3x more calcium, >9 times more magnesium, ~6x more potassium and about twice as much zinc, copper and manganese that's what buckwheat flour has to offer compared to wheat (de Francischi. 1994). If you like those figures, what about havin' one of the pancakes you see above (recipe)
    Yet, despite an increased satiety effect and improvements (increases / decreases) in the corresponding hormones
    glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP) and pancreatic polypeptide (PPY) the glucose response to the buckwheat crackers was not significantly different from the one the scientists observed after the consumption of rice crackers.

    What's intriguing, though is that it appears as if these effects were not exclusively fiber-specific. After all, the rice crackers had almost as much fiber as the buckwheat. Moreover, a 2003 study Kawa et al. confirmed that even fiber-free buckwheat extracts exert potent anti-diabetic effects, the researchers ascribed to the presence of d-chiro-inositol in the extracts (Kawa. 2003).
  • Anabolic vibes - Vibrate your way to higher testosterone levels (Couto.2013) -- If you still believe vibrators were for women only you got to check out the latest issue of the International Journal of Sports Medicine, in which a group of Brazilian scientists reports that the use of one of those fancy vibration devices (20-Hz and 12-mm) during the lat pulldown induced greater increases in testosterone and lactate concentrations. Dunno if that will also work if you just swipe your girlfriends vibrator and honestly, I don't even want to know that ;-)
  • Does the testosterone  and overall hormonal response to workouts even count, or are we still chasing a hormonal ghost? (Schoenfeld. 2013) -- In his latest review of the literature, Brad Schoenfeld who has been busy writing reviews on everything muscle heads are interested in within the last couple of weeks, picks the role of the endocrine response to exercise apart. In that, Schoenfeld points out that it is important to look close before you can tell whether or not a certain "hormone" will effect or even drive skeletal muscle hypertrophy.

    Check out this previous analysis of post-workout anabolism here at the SuppVersity (read more)
    There is for example ample evidence for the involvement of the muscle specific IGF-1 isoform IGF-1Ec, or its locally expressed splice-variant MGF and the presence of high and low responders (cf. West. 2012). Studies using its parent growth hormone, which used injections of the artificially produced recombinant growth hormone are of questionable value, since they lack the natural diversity of "growth hormones" (different GH peptides). Schoenfeld also points out that the evidence that testosterone is anabolic "is inconvertible" (Schoenfeld. 2013) and that the debate would thus have to center around its influence in the vicinity of a workout, where - and this is interesting - we actually know that the effects should occur only after the initial repression of androgen receptors is reversed.

    In accordance with what I have pointed out in the Intermittent Thoughts on Building Muscle Series Schoenfeld comes to the conclusion that it would be inappropriate to totally discard the importance of the endocrine response to workouts (IGF-1 & Co, in particular), just because it does not promote the (imho totally overrated) short term protein synthetic response to exercise:
    "Based on limited cellular signaling data, it is conceivable that the primary effect of post-exercise hormonal elevations is to increase satellite cell activity as opposed to mediating acute increases in muscle protein synthesis. If so, this could favor greater long-term increases in muscle hypertrophy without significantly impacting short-term gains." (Schoenfeld. 2013)
    Obviously (and rightly so) Schoenfeld concludes this paragraph of the discussion of this excellent review with the sentence "This hypothesis requires further study." -- And you bet, I will keep an eye on the topic in order to let you know whether the 8% of which West and Phillips say that it's the upper limit of the contribution the transient increases in endocrine hormones have on skeletal muscle hypertrophy (West. 2012) is an over- or underestimation.
  • Excess magnesium is good for your testosterone levels, bad for your prostate and could potentially become fatal for your heart (Chandra. 2013) -- According to the latest results from a rodent study, it appears as if an excess intake of magnesium, ingested not as supplement but in form of magnesium sulfate in the chow, can boost testosterone levels by almost 30% (figure 1):
    Figure 1: Testosterone  levels prostate weight, luteinizing hormone and serum magnesium levels (all data expressed relative to baseline) after 15 or 29 days on diets with different magnesium content.
    The increase in testosterone does yet not come without downsides in the form of slight, but significant increases in prostate size as well as a profound increase in magnesium levels, which would - if they were observed in human beings already mark the early stages of hypermagnesemia. So, as important an adequate amount of magnesium in your diet may be, it should be obvious that 1.5% of the diet or ~350mg/kg magnesium sulfate and thus 35mg elemental magnesium per kilogramm body weight (the HED of the dosage that was administered to the rodents; ) is simply too much - honestly, I am surprised that the rodents did not get chronic diarrhea, anyway ;-)
Since a wise man facebooked me earlier today to keep the SuppVersity posts short on this weekend, spending some time idling around, in order to avoid ending up totally burned out (I wonder if that really was an all altruistic advice of him ;-), I will now do just that - cut it short; yet not without pointing you towards the SuppVersity Facebook Wall, which does - as every day - hold 6-10 new short news for you to read up on.
 
+++ Have a nice weekend, everyone! +++

References:
  • Brede C, Fjeldal P, Skjevrak I, Herikstad H. Increased migration levels of bisphenol A from polycarbonate baby bottles after dishwashing, boiling and brushing. Food Addit Contam. 2003 Jul;20(7):684-9.
  • Chandra AK, Sengupta P, Goswami H, Sarkar M. Effects of dietary magnesium on testicular histology, steroidogenesis, spermatogenesis and oxidative stress markers in adult rats. Indian J Exp Biol. 2013 Jan;51(1):37-47.
  • Couto BP, Silva HR, Filho AG, da Silveira Neves SR, Ramos MG, Szmuchrowski LA, Barbosa MP. Acute Effects of Resistance Training with Local Vibration. Int J Sports Med. 2013 Feb 26.
  • de Francischi ML, Salgado JM, Leitão RF. Chemical, nutritional and technological characteristics of buckwheat and non-prolamine buckwheat flours in comparison of wheat flour. Plant Foods Hum Nutr. 1994 Dec;46(4):323-9.
  • DiVall SA. The influence of endocrine disruptors on growth and development of children. Curr Opin Endocrinol Diabetes Obes. 2013 Feb;20(1):50-5.
  • DWD. Press Release from February 27, 2013. < http://www.dwd.de/presse > 
  • Fierens T, Vanermen G, Van Holderbeke M, De Henauw S, Sioen I. Effect of cooking at home on the levels of eight phthalates in foods. Food Chem Toxicol. 2012 Dec;50(12):4428-35.
  • Indumathi D, Jayashree S, Selvaraj J, Sathish S, Mayilvanan C, Akilavalli N, Balasubramanian K. Effect of bisphenol-A on insulin signal transduction and glucose oxidation in skeletal muscle of adult male albino rat. Hum Exp Toxicol. 2013 Feb 19.
  • Integrated Risk Information System (IRIS). Reference Dose (RfD): Description and use in health risk assessments. 1993 < http://www.epa.gov/ncea/iris/subst/0356.htm > 
  • Kawa JM, Taylor CG, Przybylski R. Buckwheat concentrate reduces serum glucose in streptozotocin-diabetic rats. J Agric Food Chem. 2003 Dec 3;51(25):7287-91.
  • Koch HM, Lorber M, Christensen KL, Pälmke C, Koslitz S, Brüning T. Identifying sources of phthalate exposure with human biomonitoring: Results of a 48h fasting study with urine collection and personal activity patterns. Int J Hyg Environ Health. 2013 Jan 17. 
  • Makris Kc, Andra S, Jia A, Herrick L, Christophi C, Snyder Sa, Hauser R. The Association Between Water Consumption From Polycarbonate Containers And Bisphenol-A Intake During Harsh Environmental Conditions in Summer. Environ Sci Technol. 2013 Feb 28.
  • Mendez, A M, Pera G, Agudo A, Bueno-de-Mesquita HB, Palli D, Boeing H, Carneiro F, Berrino F, Sacerdote C, Tumino R, Panico S, Berglund G, Manjer J, Johansson I, Stenling R, Martinez C, Dorronsoro M, Barricarte A, Tormo MJ, Quiros JR, Allen N, Key TJ, Bingham S, Linseisen J, Kaaks R, Overvad K, Jensen M, Olsen A, Tjønneland A, Peeters PH, Numans ME, Ocké MC, Clavel-Chapelon F, Boutron-Ruault MC, Trichopoulou A, Lund E, Slimani N, Jenab M, Ferrari P, Riboli E, González CA. Cereal fiber intake may reduce risk of gastric adenocarcinomas: the EPIC-EURGAST study. Int J Cancer. 2007 Oct 1;121(7):1618-23.
  • Nagy-Szakal D, Hollister EB, Luna RA, Szigeti R, Tatevian N, Smith CW, Versalovic J, Kellermayer R. Cellulose supplementation early in life ameliorates colitis in adult mice. PLoS One. 2013;8(2):e56685. 
  • Plante TG, Cage C, Clements S, Stover A. Psychological benefits of exercise paired with virtual reality: Outdoor exercise energizes whereas indoor virtual exercise relaxes. International Journal of Stress Management, Vol 13(1), Feb 2006, 108-117
  • Roth J, Mobarhan S. Preventive role of dietary fiber in gastric cardia cancers. Nutr Rev. 2001 Nov;59(11):372-4.
  • Schoenfeld B. Post-exercise hypertrophic adaptations: A re-examination of the hormone hypothesis and its applicability to resistance training program design. J Strength Cond Res. 2013 Feb 25. 
  • Sleeges PJC, Moolenaar MN, Galetzka M, Pruyn A, Sarroukh BE, van der Zande B. Lighting affects students’ concentration positively: findings from three Dutch studies. Lighting Research and Technology. June 22, 2012.
  • Stringer DM, Taylor CG, Appah P, Blewett H, Zahradka P. Consumption of buckwheat modulates the post-prandial response of selected gastrointestinal satiety hormones in individuals with type 2 diabetes mellitus. Metabolism. Available online 26 February 2013.
  • Terry P, Lagergren J, Ye W, Wolk A, Nyrén O. Inverse association between intake of cereal fiber and risk of gastric cardia cancer. Gastroenterology. 2001 Feb;120(2):387-91
  • West DW, Phillips SM. Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training. Eur J Appl Physiol. 2012 Jul;112(7):2693-702.  
  • Wu MT, Wu CF, Chen BH, Chen EK, Chen YL, Shiea J, Lee WT, Chao MC, Wu JR. Intake of phthalate-tainted foods alters thyroid functions in taiwanese children. PLoS One. 2013;8(1):e55005.