Oups désolé, je n'avais même pas capté que c'était une boutique
Mais du coup j'ai pas eu de réponse alors que c'était un article intéressant sur ce produit
Je vais coller le texte de l'article en espérant que ça ne pose pas de problème...
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
The Myth Of Waxy Maize Starch And The Truth Behind It All!David Barr - August 29, 2017
(j'ai un gros doute sur la date...)Although bringing you to the cutting edge is usually very exciting, I sometimes have to become the Mythbuster. Today that myth lies squarely in the face of waxy maize starch and if it's worth the price
Although bringing you to the cutting edge is usually very exciting, there's a darker side that must often emerge: when I have to don the mask and become sports nutrition's Mythbuster.
Sure I've created some of the most prominent tombstones in the graveyard: glutamine, arginine (a.k.a. "nitric oxide"), anti-creatine, and even the post-workout window have fallen to my blade.
But every time there's a backlash, as companies scramble to bury the data, younger individuals get angry as their underdeveloped prefrontal cortices hold reason captive. But this time it's worse. This time, I may have inadvertently helped create the myth. It's the myth of Waxy Maize Starch (WMS), and it's time for me to pay the price.
What Is Waxy Maize Starch?
Before we get to the actual myth, we should take a look at what we're talking about. In fact, some of the mythology lies in the fundamental misunderstanding of what WMS really is.
Waxy starches are carbohydrates derived from various sources such as rice, barley, and corn (i.e. maize). The "waxy" part refers to the fact that under a microscope there exists a resemblance to actual wax, although this it does so in appearance only.
The main characteristic of waxy starches is that they generally contain a large amount of highly branched starch called amylopectin. Specifically, waxy starches are defined as having an exceptionally high amylopectin content - the remaining being comprised of the less branched amylose (8, 12).
Amylopectin
Amylopectin is a highly branched polymer of glucose found in plants. It is one of the two components of starch, the other being amylose. It is soluble in water.
Considering that many of us have used WMS specifically for the purposes of post-workout glycogen restoration, you may be interested to know that the highly branched glucose subunits of amylopectin essentially make it the plant version of glycogen. Amylose on the other hand, is less branched and in theory, more slowly digested (3, 13, 15).
The reason behind their relative digestion rate is due to the fact that enzymes have greater access to the glucose subunits in the highly branched structure. At least that's how it should work. It's worth noting that along with the degree of branching comes the giant molecular weight of amylopectin, which contributes directly to the mythology.
The Myth Itself
Now that we understand what we're talking about, it's time to look at the actual tale. Essentially, the myth states that WMS is a very fast carbohydrate because of its high amylopectin component (>99%), and subsequent enormous molecular weight (this explains why some companies simply call their WMS "amylopectin").
It's further stated that because of this molecular weight, WMS is absorbed by the gut more quickly than dextrose or maltodextrin -the archetypical "fast carbs"- which in turn results in much greater glycogen storage. Some claims go so far as to specify that WMS is absorbed, or will restore muscle glycogen, ~70-80% faster than other quick sources.
Unfortunately, these claims just cannot be substantiated. In fact, there are very few studies even performed on WMS, and they're not at all what you might expect. Fortunately, the earliest research on WMS not only used exercise, but did so in trained athletes, making their results more relevant. Let's take a closer look.
The WMS Study Summaries
The first study compared way maize to dextrose, slow starch, and a placebo (4). In contrast to common claims, following ingestion, both blood glucose and resulting insulin levels were similar between WMS and slow starch, and 3 times lower than plain dextrose. Measured work output during cycling exercise was not different following either dextrose or WMS ingestion, which were similar to slow starch.
1 Blood Sugar And Insulin Were Similar To Slow Starch, But Much Lower Than Dextrose
The next study examined 24-hour glycogen resynthesis using WMS, maltodextrin, dextrose, or slow starch (6). WMS-induced glycogen storage and subsequent work performance were not different from that of dextrose or maltodextrin consumption. It wasn't all bad news however, as these three carbohydrates yielded improved performance over slow starch.
A more recent study looked at WMS (a.k.a. "amylopectin") compared to maltodextrin, sucrose (a.k.a. table sugar), and slow starch, using a 1-hour glycemic index test (conducted by one of the researchers who invented it back in the 1980's)(1).
Once again, WMS performance contradicted the frequent claims about apparent rapid absorption. This time, blood glucose levels were not only lower than maltodextrin, but lower even than the slower carbohydrate sucrose. In fact, the glycemic response of WMS was low enough for researchers to call it a "low-glycemic-index treatment", like the slow starch.
3 Blood Glucose Levels Lower Than Maltodextrin And Sucrose
Far from an isolated incident, a brand new study sought to specifically investigate the glycemic response of WMS ingestion compared to both maltodextrin with a small amount of sucrose, and white bread (10).
Interestingly, the resulting blood glucose response of WMS was similar to that of bread! As you'd expect, this was quite a bit lower than the fast carb mix of maltodextrin + sucrose. Additionally, the insulin response was significantly lower for WMS even compared to the bread treatment (and of course much lower than maltodextrin).
4 Blood Glucose Similar To, And Insulin Lower Than, White Bread
A final study compared the glycemic response of 25g WMS that was cooked with water into a paste, to that of the same amount of glucose (5). This study is different from the previous WMS studies that used uncooked "native" WMS. The blood sugar levels were similar between groups, leading the researchers to give the WMS a glycemic index rating of 90.
5 Similar Blood Sugar Response As Dextrose
If we're dissecting the information on WMS -as we should be, especially if we're thinking of spending money on it- then we need to evaluate the glycemic index itself.
Although a full discussion is beyond the scope of this article, it's worth noting that simply measuring blood sugar isn't ideal for a complete understanding of this substance. Adding insulin measurements helps a great deal, although this is still not perfect (for a full review, see 14).
At the same time, it's critical to understand that the purpose of this review is to evaluate the claims surrounding WMS, and then determine how they match up with the available information. Clearly they don't.
A Leap Of Faith
Looking at the above summaries there seem to be discrepancies. After all, the responses range from being slightly worse than dextrose (5), to much worse than dextrose (4) or sugar and maltodextrin (1), to even worse than bread (10). While none of these probably make you want to use WMS, or support the predominant claims about it, the differences are enough to make you wonder what's going on.
After contacting National Starch and Chemical Company (NS) I discovered that there are different preparation methods for waxy maize. These treatments can change the properties of WMS such that it may be absorbed differently. For example, cooked starch is more readily absorbed than the native uncooked version.
I must admit that this gave me a glimmer of hope as I quickly jumped on the idea that any WMS available for sale would only use the fastest "type". Unfortunately this was short lived as the realization set in that the "rapidly hydrolyzed" starch from NS (11), called AMIOCA, actually yielded some of the worst performance results when compared to actual fast carbohydrates (1, 4).
History Of Waxy Maize
The exact history of waxy maize is unknown. The first mentions of it were found in the archives of the U.S. Department of Agriculture (USDA).
In 1908, the Rev. J. M. W. Farnham, a Presbyterian missionary in Shanghai, sent a sample of seeds to the U.S. Office of Foreign Seed and Plant Introduction. A note with the seeds called it: "A peculiar kind of corn. There are several colours, but they are said to be all the same variety.
The corn is much more glutinous than the other varieties, so far as I know, and may be found to be of some use, perhaps as porridge." These seeds were planted on May 9, 1908, near Washington, D.C., by a botanist named G.N. Collins.
He was able to grow 53 plants to maturity and made a thorough characterisation of these plants, including photographs, which were published in a USDA bulletin issued in December 1909. In 1915, the plant was rediscovered in Upper Burma and in 1920 in the Philippines. Kuleshov, when screening the distribution of maize in Asia, found it in many other places.
The discrepancies lie in the fact that the "rapidity" was originally determined with digestive enzymes in a test tube (11), or was relative to a very slow starch (1, 11). From this we can see that in contrast to original opinion, amylopectin content is not synonymous with fast digestion or absorption.
NOTE: The company themselves have no glycemic data on this product, making this the first (and currently only) literature review of WMS in existence.
So the fastest WMS might be almost as good as dextrose or maltodextrin, but how can we be sure what kind we're getting? Naturally you wouldn't expect anyone to admit that they're selling the "slower" types of WMS, and considering the other claims that have been made...
Come to think of it, the absence of information available makes me wonder if anyone knows what's being ingested.
Full Investigation
To reiterate, not only do the available data fail to support any of the claims made about WMS, they seem to contradict it! At this point I began to feel as though I was missing something. So just to make sure that I covered everything, I contacted 5 of the biggest supplement companies that sell WMS products.
Sadly, in spite of their claims, those that actually tried to help me couldn't provide any research on WMS at all. Not exactly a confidence booster. Chances are, if they're reading this report then they're learning right in step with you that there are studies on WMS - and they ain't what they expected...
The Myth Is Spawned
So where did this myth come from? After all, there has to be something to it if it's as pervasive as it is. The fable was actually created from the erroneous application of two very powerful carbohydrate studies (7, 9).
These studies used a carbohydrate extract called *****, and were referenced on the label of a now-defunct product containing this carb. When we looked at the label it was clear that this supplement had derived their ***** (which again, is a carbohydrate extract) from... drum roll please... waxy maize!
And the myth was born: research showing that ***** had rapid gastric clearance and glycogen restoration was equated with the idea that high molecular weight carbohydrates (i.e. WMS/amylopectin) had these properties.
Just take a look at any supposed WMS references, if you can find them, and you'll see at least one of these studies listed: Leiper et al., (2000) or Piehl Aulin et al. (2000). In fact, this is also where the often-specified gastric emptying, rate of absorption, and glycogen resynthesis numbers come from.
Perhaps the worst part is that these studies not only used *****, they did not derive it from waxy maize! That's right, the commonly cited WMS data actually used a carbohydrate extracted from potato starch (7, 9). As if to add a final comical exclamation point, the potato starch itself wasn't even the waxy variety.
Summary: The most common "information about waxy maize" comes from a carbohydrate extract that wasn't originally waxy nor even derived from corn.
This is a worse connection than saying that Nobel Prize-winning research for the discovery of nitric oxide has any relevance for athletes taking arginine!
Conclusions And Questions
So in spite of hours of investigation, I just couldn't find any reason to use WMS. Even speaking to a dozen or so people from the companies that sell it, couldn't provide me with one single study about this substance. Worse than simply not being able to justify claims about its rapidity, most of the available information suggests that WMS is a poor carbohydrate to use after training.
To put all of this in perspective, it's possible that the WMS we're using has worse digestive/absorptive properties than white bread. We can hope that our product contains "faster" WMS, which will undoubtedly become the new claim, but even at best this is similar to dextrose and maltodextrin. Considering that dextrose is the cheapest supplement in existence, this begs the question: what are we paying for?
Q
Do you work for a competitor who wants to hurt WMS sales?
Sadly no. The 100+ hours I've put into this investigation are all pro bono. I'll consider it penance for having mentioned WMS in the past. Interestingly, even if I were the CEO of a competing company, it wouldn't impact the scientific literature or the unsupported claims.
You're wrong, I know WMS works
This review isn't suggesting that WMS can't restore muscle glycogen, it simply shows that at best it is not superior to dextrose or maltodextrin. Of course we can't personally determine whether our gastric emptying is superior to other fast carbs - even taking blood sugar measurements is not sensitive enough to ascertain this.
To date, there are no comparison gastric emptying studies with WMS. Lastly, don't forget that this is an investigative literature review, not an opinion piece.
I am mad about the presentation of this information. Does that make me a moron?
No, just human. You're experiencing something called cognitive dissonance or true-believer syndrome, both of which are natural psychological phenomena. In time, reason should prevail, but for now it's important enough to recognize that your judgment is being affected.
Cognitive Dissonance & True-Believer Syndrome
Cognitive dissonance is an uncomfortable feeling caused by holding two contradictory ideas simultaneously. The "ideas" or "cognitions" in question may include attitudes and beliefs, and also the awareness of one's behavior.
True-believer syndrome is a term coined by M. Lamar Keene in his 1976 book The Psychic Mafia. Keene used the term to refer to people who continued to believe in a paranormal event or phenomenon even after it had been proven to have been staged.
What if I still want to use WMS products?
This literature review isn't about telling you what to do; it's about giving you the information with which to make an educated decision. Whether or not you choose to risk your performance and money has no bearing on whether someone else may not want to take those risks. It's ultimately your choice, and you deserve to have all of the information with which to make it.
References Anderson GH, Catherine NL, Woodend DM, Wolever TM. Inverse association between the effect of carbohydrates on blood glucose and subsequent short-term food intake in young men. Am J Clin Nutr. 2002 Nov;76(5):1023-30.
Behall KM, Scholfield DJ, Canary J.Effect of starch structure on glucose and insulin responses in adults. Am J Clin Nutr. 1988 Mar;47(3):428-32.
Brighenti F, Benini L, Del Rio D, Casiraghi C, Pellegrini N, Scazzina F, Jenkins DJ, Vantini I. Colonic fermentation of indigestible carbohydrates contributes to the second-meal effect. Am J Clin Nutr. 2006 Apr;83(4):817-22.
Goodpaster BH, Costill DL, Fink WJ, Trappe TA, Jozsi AC, Starling RD, Trappe SW. The effects of pre-exercise starch ingestion on endurance performance. Int J Sports Med. 1996 Jul;17(5):366-72.
He J, Liu J, Zhang G. Slowly digestible waxy maize starch prepared by octenyl succinic anhydride esterification and heat-moisture treatment: glycemic response and mechanism. Biomacromolecules. 2008 Jan;9(1):175-84.
Jozsi AC, Trappe TA, Starling RD, Goodpaster B, Trappe SW, Fink WJ, Costill DL. The influence of starch structure on glycogen resynthesis and subsequent cycling performance. Int J Sports Med. 1996 Jul;17(5):373-8.
Leiper JB, Aulin KP, S?derlund K. Improved gastric emptying rate in humans of a unique glucose polymer with gel-forming properties. Scand J Gastroenterol. 2000 Nov;35(11):1143-9.
Li JY, Yeh AI. Relationships between thermal, rheological characteristics and swelling power for various starches, J. Food Engineering 2001 50:141-148.
Piehl Aulin K, S?derlund K, Hultman E. Muscle glycogen resynthesis rate in humans after supplementation of drinks containing carbohydrates with low and high molecular masses. Eur J Appl Physiol. 2000 Mar;81(4):346-51.
Sands AL, Leidy HJ, Hamaker BR, Maguire P, Campbell WW. Consumption of the slow digesting starch waxy maize leads to blunted and sustained carbohydrate utilization but does not influence energy expenditure or appetite. FASEB J. 2008;22:1089.2
Seal CJ, Daly ME, Thomas LC, Bal W, Birkett AM, Jeffcoat R, Mathers JC. Postprandial carbohydrate metabolism in healthy subjects and those with type 2 diabetes fed starches with slow and rapid hydrolysis rates determined in vitro. Br J Nutr. 2003 Nov;90(5):853-64.
Singh N, Singh J, Kaur L, Singh Sodhi N, Singh Gill B. Morphological, thermal and rheological properties of starches from different botanical sources. Food Chem. 2003 81:219-231.
van Amelsvoort JM, Weststrate JA. Amylose - amylopectin ratio in a meal affects postprandial variables in male volunteers. Am J Clin Nutr. 1992 Mar;55(3):712-8.
Venn BJ, Green TJ. Glycemic index and glycemic load: measurement issues and their effect on diet-disease relationships. Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S122-31.
Zhang G, Venkatachalam M, Hamaker BR. Structural basis for the slow digestion property of native cereal starches. Biomacromolecules. 2006 Nov;7(11):3259-66.
par rico la grenade » 29 Oct 2016 21:03 
).
