Thursday, August 29, 2013

Fast Absorbed High Molecular Weight Resistant Starches Make a Comeback in Diabetic Formula: Are RS-4 (WM-HDP) Based Products An Ideal Meal Replacement for Diabetics?

Pick your metaphor: Clutching to a straw, or hobbling around on a crutch
If type II diabetics were into quasi tube-feeding (=living of meal replacements) or adhering to any diet of some sort, the study Cruz Erika Garcia-Rodriguez and colleagues have recently published in the European Journal of Nutrition could actually be help us solve the to diabesity problem. For me it is  however more of a good reason to take another look at what became of RS-4 (resistant start type 4 = synthetic resistant starches made from waxy maize or tapioca; learn more).

I mean, do we have good reason to mourn, now that Myotropics ThermiCarb(TM) is gone and no legitimate and reasonably prized follow-up product is available?

The stuff still works, but does it also help?

Aside from the fact that I personally consider the idea to feed diabetics liquid foods ludicrous and counter-productive (you do not heal a cripple if you hand him a crouch), the latest results Garcia-Rodriguez et al. present in their paper confirm what we already knew: RS-4 is a non-insulinogenic carbohydrate source that produces
  • higher levels of the incretin hormones ghrelin, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), and
  • lower levels of insulin and C-peptide compared to iso-energetic "regular carbs" 
at least in the 24 healthy individuals (BMI 23.2kg/m²) who participated in the study at hand. For their type II diabetic counterparts (BMI 35.5kg/m²; HnA1C 8.3%), on the other hand, a significant reduction in postprandial glycemia was the only advantage the researchers could detect.

Diabetic diet formula wars

The actual product the scientists evaluated for their sponsors from Vegenat S.A was albeit not a simple WM-HDP (=waxy maize Hydroxypropyl-Distarch Phosphate) powder.
Table 1: Nutrient composition of formulas used in the study (Garcia-Rodriguez. 2013)
"The tested DSF (T-Diet Plus Diabet NP, Vegenat S.A., Spain) [...] provided 402 kcal/845 kJ (400 ml serving) with 32 g as CHO (40 % of energy), 20.1 g as fat (45 % of energy) and 22 g as protein (15 % of energy) and contained a mixture of vegetable and fish oils (20 mg/dl of eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA)). It also included 7.2 g (20 % on total CHO) of fibre content (inulin and cellulose 20/80 wt/wt). The CHO in this new DSF was low dextrose equivalent (DE) purified and atomized maltodextrins (5–8 DE) (31.7 %) obtained by the hydrolysis of starch, and RS type IV (53.7 %) obtained from partially hydrolysed maize starch by heating in the presence of food grade acid. [...]

The CP [control] was a normoproteic and normocaloric diet which differed to T-Diet Plus Diabet NP in its CHO composition, containing 18–20 DE purified and atomized maltodextrins (99.4 %) obtained by the hydrolysis of starch, and in its fibre content, that is, inulin- and cellulosefree." (Garcia-Rodriguez. 2013)

In contrast to the healthy subjects, on whom the scientists tested only the carbohydrate fraction of this new product the 10 diabetics consumed different commercially available nutritionally complete liquid diet supplements, i.e. T-Diet Plus Diabet NP (Vegenat S.A., Spain), Glucerna SR (Abbott Laboratories, Chicago, IL, USA) and Novasource Diabet (Nestlé Healthcare Nutrition, Switzerland) in 400ml servings after an overnight fast.
Figure 1: Area under the curve (AUC) for biochemical parameters and gastrointestinal hormones in diabetic (left) and healthy volunteers (Garcia-Rodriguez. 2013)
As the data in figure 1 (left) goes to show you, the real-world differences between the products were yet by far less earth-shattering, than you may have expected; and that despite significant differences in their carbohydrate make-up:
  • Glucerna SR contains a complex carbohydrate mixture consisting of fructose (22.9 %) and slowly digestible maltodextrins (49.9 %). It also includes shortchain fructo-oligosaccharides and fibre (6.9 % on total CHO). 
  • Novasource, on the other hand is, based on starch (84 %) and fructose (24 %) as well as fibre (11.7 % on total CHO).
Compared with Glucerna SR and Novasource the product of the study sponsor was also the only one with significant amounts of n-3 fatty acids from plant (linoleic and linolenic acid) and marine sources (EPA+DHA). And still,  as a comparison of the response of the healthy subjects to the same product vs. a regular maltodextrin based formula shows. Neither the lower insulin, c-peptide, triglyceride and GIP levels (all beneficial for weight loss) nor the non-significantly increased GLP-1 levels the scientist observed in the lean individuals were present in the overweight diabetics.

It should be mentioned, though that the control supplement for the healthy individuals was not identical to any of the two formulas that were compared to T-Diet Plus in the experiment with the diabetics. Whether the differences between T-Diet Plus and a "regular" meal replacement would be more pronounced would thus still have to be tested in diabetics.

Certainly no food for diabetics, but as workout fuel for lean athletes RS-4 pancakes could still be useful (more)?
Bottom line: Questionable weight benefit and non-existent anti-diabetic effects - that certainly sounds like any of the commercially available mainstream weight loss products and or meal replacements for diabetics. The significant decrease in blood glucose AUC after the ingestion of the RS4-powered formula, however, could still make a significant health benefit. Just like the crutch that helps you to walk from A to B without straining an already injured ankle even further, RS4 based products could help type II diabetics control their blood glucose levels more than the fructose + regular starch based competition and that would directly reduce the risk of complications!

However, other than real food and lifestyle changes esp. exercise / general physical activity, by the means of which more than half (∼54%) of the patients in the often-quoted Malmö study improved their oral glucose tolerance to an extend that their blood glucose levels were no longer in the critical range (Eriksson. 1999), consuming resistant starches does not have the potential to eradicate diabetes.

References:
  • Eriksson KF, Lindgärde F. Prevention of type 2 (non-insulin-dependent) diabetes mellitus by diet and physical exercise. The 6-year Malmö feasibility study. Diabetologia. 1991 Dec;34(12):891-8.
  • García-Rodríguez CE, Mesa MD, Olza J, Buccianti G, Pérez M, Moreno-Torres R, Pérez de la Cruz A, Gil A. Postprandial glucose, insulin and gastrointestinal hormones in healthy and diabetic subjects fed a fructose-free and resistant starch type IV-enriched enteral formula. Eur J Nutr. 2013 Sep;52(6):1569-78.

31 comments:

  1. I usually mix about 20 grams of Thermicarb with a cup of water and some stevia and cinnamon to make a nice tasty paste. I then proceed to dip veggies such as celery in it to eat. Maybe the diabetics could try that lol

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    1. If you have a pre-gelatinized HDP like thermicarb you can just mix it 1:2 with a flavoured micellar casein and 5x the amount of skim milk, put it in the fridge for 15 minutes and make yourself a very tasty pudding.

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    2. Nice BB! Normally I will use a scoop of thermicarb (20g) and mix with a cup of cold water with flavorings and stevia to make a nice dip for vegetables.

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  2. What an unexpected article! I have been interested in resistant starch for quite some time, I'd like to share a bit with you.

    Resistant starch works mainly due to it's interactions with gut microflora. Beneficial bacteria, aka 'probiotics' feed preferentially on resistant starch. When given enough, they will outnumber pathogenic bacteria in the large intestine and allow our digestive and endocrine systems to work like they're supposed to. Beneficial bacteria also exert a powerful gut-brain interaction--serotonin is produced mainly by beneficial bacteria. People who consume approximately 20-30g of RS per day see almost immediate changes in sleep, digestion, and glucose control.

    Where can I buy these fantastic RS supplements you ask? They are available in nearly every grocery store in the world, they are pretty expensive, though--$5 for a 60 day supply!

    RS is found in many foods, and there are 4 types:
    RS1 is found in seeds and nuts
    RS2 is found in raw potatoes, certain corn, and green bananas
    RS3 is found in potatoes and rice that has been cooked and then cooled
    RS4 is found in a pharmacists lab--it does not occur in nature

    Through a bit of trial and error, and reading countless papers on RS, I noticed that in most of the RS studies, the scientists were using raw potato starch as a control RS to compare to RS4. In almost every respect, raw potato starch outperforms the many types of RS4 that has been developed.

    There's your magic supplement! Potato starch. As long as it's unmodified and not heated above 150 degrees it is nearly pure RS2. It's actually about 80% by weight, so 1TBS contains about 8g of RS. Tapioca starch/flour is almost the same percentage of RS as potato starch, and plantain flour is about half as potent.

    Real foods can be used to obtain RS, but usually at a high calorie cost. An entire cooked potato has about 2-3g of RS, a cooled potato has about 5g. A green banana has about 15g, a raw, green plantain has about 30g (delicious when dried).

    I have been working with blogger Richard Nickoley to get this information as widely disseminated as possible. So far we have gotten close to 100 people to give it a try, most supplementing with 1-4TBS per day of potato or tapioca starch and experimenting with food sources like beans, plantains, potatoes, etc...

    Please take a look at the blog, Free the Animal, for proof that it works, science behind why it works, and ideas for how to incorporate RS into your life very cheaply.

    Here's a link to Richard's latest RS blog with links to all the rest: http://freetheanimal.com/2013/08/resistant-starch-content-of-foods-other-anecdote-and-miscellania.html

    Here's a study on the differences between RS2 and RS4: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0015046

    If you carefully read the study, the reason that natural RS works best is because probiotic strains of bacteria can actually cleave onto and etch themselves into the starch granules, so attached, they can survive the trip through the stomach and small intestine and survive to populate the large intestine. For this reason, many people have taken to mixing raw starch with milk, kefir, or yogurt.

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    1. lol reading this post it seems like the first half came from wikipedia, and the second part is just pimping potato starch, which is FAR different from RS4 starch. So much so that I don't understand why they are promoting them as being on the same level (even the last study linked concludes they are different).

      And to directly respond to the above post, RS2 starch does not out perform RS4 starch. Furthermore, there are very few studies that even look at RS4 starch.

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    2. I'm not sure I understand your point? So potato starch isn't resistant starch?

      And resistant starch doesn't help w/ blood glucose levels and function as a prebiotic?

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    3. That is not what I said at all; I said that RS2 and RS4 starches are different. Both starches help with blood glucose control and function as prebiotics, but RS4 starch also acts to increase fat oxidation and can be thought of as a "super" starch that really outperforms the others.

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    4. It doesn't take much goggle-ing to figure out that there is no magic to RS4. Actually lots of studies on RS2 and 4 compared. It seems to me that what manufacturers of RS4 are up against is finding one that compares to native starches, especially potato, or even Hi-Maize. Lots of studies on RS2 and fat oxidation.

      A huge benefit of RS2 over RS4 is the ability of probiotics to cling to RS2 granules and survive the stomach and small intestine. RS4 does not do this.

      But, I was really hoping that Dr. Andro would be sparked into researching and writing on RS2 from potato/tapioca starch and green banana flour as a prebiotic supplement from real food sources as opposed to man-made/processed RS4.

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    5. The primary difference is that RS4 has a significantly higher molecular weight. HDP is typically made from chemically modified potato, tapioca or maize starch for this exact purpose and trait. Like Primalkid I can't recall a single study showing RS2 to outperform RS4. In fact the handful of studies on RS4 directly show that it outperforms other RS starches in many regards, by significant numbers. I'm also not quite sure where you are headed with your rant against "the manufacturers" since RS4 has been used in the food industry for a long time as a thickening and shining agent. It's in instant puddings, in baby food (to help increase satiety) and what not.

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    6. My rant is aimed primarily at Ingredion, formerly National Starch, proud producers of high fructose corn syrup. Since the fall of HFCS, they have been pushing their Hi-Maize RS product, hoping to get it into every loaf of bread and donut in the world. All I see from this is misery--more people eating more processed wheat products in the name of health.

      My technique when reading studies is always to 'follow the money'. What I found in doing so is that studies proclaiming the wonders of RS4 and Hi-Maize are paid for by the companies that produce these products. However, it dawned on me one day that almost all of them were using raw potato starch as a control in many studies. I thought, 'why not just use potato starch?' and it opened a lot of doors in my research on RS.

      Potato starch is not considered a food in it's raw state so it escapes consumers attention that it is almost pure resistant starch. Tapioca starch and plantain flour also fit the bill.

      RS4 may indeed show superior in certain trials and certain parameters--being able to withstand heat of cooking is something potato starch will never be able to do. As a bifidogenic agent, however, native/raw starches of plantain, potato, and tapioca (cassava) stand alone. Also, their ability to be used as a symbiot are unique. Lacto and bifido bacteria are capable of cleaving on and etching into raw starch granules. This happens as soon as ph conditions allow, so mixing yogurt, kefir, or fermented veggies with native potato starch while consuming allows the bacteria to get through the stomach and small intestines intact. This is shown not to happen with RS4. Look into 'encapsulation of probiotics', lots of money being spent on this right now.

      RS has largely escaped attention of everyone, but as it gains attention I like to point out it can be had from sources besides man-made or grain-based products.

      Sorry for the anonymous tag, I don't have a google ID. I'm 'Tatertot' in all the links I posted above.

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  3. Alex - You are a student, right? Considering pursuing a Master's in Diet. If you ever need a paper idea or a thesis, here's a good one: The use of native starches from potato, tapioca, and plantain as prebiotic supplements for humans.

    Go to the Free the Animal links above, look at all the research and theses we have presented, and keep an open mind. In every study, ask yourself--'why not just use potato, tapioca, or plantain starch?' That's what I did.

    Most of the studies are backed by someone with an angle (money) and trying to find novel uses for agriculture products (wheat, corn, barley, etc...). As a paleo/primal kind of guy, you should see the brilliance in getting all the prebiotics you need from a simple, unprocessed source. It kind of 'sticks it to the man' getting this info out there. The maker's of Hi-Maize have spent millions on studies, but their product has nothing unique over potato starch except that it can be used in baking.

    It's simply the shape and structure of the starch granules that make them resistant to digestion by humans. No magic. Most people are sorely lacking in prebiotic support of gut flora. What needs to be figured out is exactly how much prebiotic substance is needed and what is the best source, or combination of sources. Very little research in this area, but with gut microbe sequencing science speeding up, it's ripe for the picking.

    http://freetheanimal.com/2013/08/resistant-starch-content-of-foods-other-anecdote-and-miscellania.html Spend a couple hours clicking links and reading studies--you'll be amazed what you find with an open mind.

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    1. Anonymous, I completely agree with what you are getting at. I eat potatoes and sweet potatoes as my main starch sources. I understand the whole prebiotic thing and agree with you 100% that people need to eat more whole foods that deliver this type of sustenance, especially with so much emerging research looking at the influence of the gut microbiome on many health parameters in humans (speaking of which, this paper may interest you ==> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3402009/).

      However, the point I was trying to make is exactly what Belgian Blue pointed out above: RS4 starch is superior to RS2 starch. This is not saying RS2 should not be consumed, quite the opposite since replacing all RS2 sources with RS4 would be absurd. However, nothing as of yet can compare to the powers of RS4.

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    2. Great study you linked, I had not seen that before. One thing that is missing from the study is a discussion on the role of resistant starch in an ancestral diet. Coprolite (fossil poop) studies have found ancient H-G people ate tons and tons of fermentable fibers from inulin containing plants and raw starchy tubers like cattail roots, potatoes, plantains, cassava, sago palm, and many other plants we wouldn't recognize as foods today. Bottom line, though, they used to eat lots of food that led to healthy gut microbe communities.

      Here's a couple good studies for you to look at, not necessarily saying RS2 is better than RS4, but well-designed studies.

      Microbial shifts in relation to RS feedings over other foods-- http://www.nature.com/ismej/journal/v5/n2/full/ismej2010118a.html

      RS3 was demonstrated to produce more SCFAs compared with RS2 and RS4. - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3735574/

      A study showing great promise for RS4 over regular starch and sugar--not comapred to RS2 or native starches. Note the Financial Interests: Dr. Seib invented RS4XL and has been a Consultant with MGP Ingredients, Inc. for 20 years. MGP Ingredients, Inc. helped support the study by providing RS4XL and funding part of the data collection. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2925102/

      My intent is not to bury you in studies, just for your perusal...I'm not interested in a drawn-out debate. I will concede you guys have found a good use for RS4 and I'm glad it works!

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  4. Hi Tatertot,

    just wanted to ask you: how did you come to the values of 15 gr of RS per green banana and 80% for potato starch?

    My researches ponted out from 54% to 70-something% (depending on the study) for the RS in potato starch and another 70-something% for RS in green banana starch, so for every 100 grs of green banana it should be 10 grs of RS or less, depending from the fact whether carbs in GB are all starch or part starch, part other mono/di-saccarides...

    Could you please let me know??

    Thank you

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  5. ...also, you state in your pdf paper that 100 grs of unripe banana could countain up to 34 grs of RS, but how is it possible if bana has 15 grs of carbs x 100 grs??

    Or have I interpreted the paper wrong?

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    1. not sure, which PDF, by the way? Bananas have 25g of carbs, but I suspect I may have mixed up a large banana with 100g of banana

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    2. hold on, you talk to "Anonymous" right?

      Well let's see http://jn.nutrition.org/content/128/3/651.abstract says a Banana has 31.6g of potentially available starch and 72.1% of those are resistant starches when the banana is still green.

      compare

      Spaghetti 5% RS
      Rice 4.9% RS
      Potato boiled & stored cool 7.0%
      - just boiled 3.7%

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    3. RS contents in foods is a slippery subject. I went through dozens of studies and came up with this master list showing the ranges and methods used to obtain the readings: http://freetheanimal.com/wp-content/uploads/2013/08/Resistant-Starch-in-Foods.pdf

      Potato Starch is on page 5. Three studies placed it between 66% and 79%. Bananas are on page 4 and you'll see a wide range from .3% to 34%. As a banana ripens, it loses RS.

      Here is a new paper I just saw last week: http://onlinelibrary.wiley.com/doi/10.1111/1750-3841.12165/abstract?systemMessage=Wiley+Online+Library+will+be+unavailable+for+approximately+4+hours+between+09%3A00+EDT+and+14%3A00+EDT+on+Saturday%2C+28+September+2013+as+we+make+upgrades+to+improve+our+services+to+you.+There+will+also+be+some+delays+to+online+publishing+between+25+to+28+September+2013.+We+apologize+for+the+inconvenience+and+appreciate+your+patience.+Thank+you+for+using+Wiley+Online+Library!&userIsAuthenticated=false&deniedAccessCustomisedMessage=

      Abstract only, I have the full text on pdf, nothing shocking that's not in the abstract. Bottom-line, you can increase the RS in rice by cooking, chilling, and then frying in oil. This takes into account several of the properties of RS formation: Swelling of starch granules, retrograde production of resistant starch, and the RS preservation of cooking at high, dry heat vs. moist heat.

      From the abstract:
      "This study aimed to understand effects of different cooking methods, including steamed, pilaf, and traditional stir-fried, on starch hydrolysis rates of rice. Rice grains of 3 varieties, japonica, indica, and waxy, were used for the study. Rice starch was isolated from the grain and characterized. Amylose contents of starches from japonica, indica, and waxy rice were 13.5%, 18.0%, and 0.9%, respectively. The onset gelatinization temperature of indica starch (71.6 °C) was higher than that of the japonica and waxy starch (56.0 and 56.8 °C, respectively). The difference was attributed to longer amylopectin branch chains of the indica starch. Starch hydrolysis rates and resistant starch (RS) contents of the rice varieties differed after they were cooked using different methods. Stir-fried rice displayed the least starch hydrolysis rate followed by pilaf rice and steamed rice for each rice variety. RS contents of freshly steamed japonica, indica, and waxy rice were 0.7%, 6.6%, and 1.3%, respectively; those of rice pilaf were 12.1%, 13.2%, and 3.4%, respectively; and the stir-fried rice displayed the largest RS contents of 15.8%, 16.6%, and 12.1%, respectively. Mechanisms of the large RS contents of the stir-fried rice were studied. With the least starch hydrolysis rate and the largest RS content, stir-fried rice would be a desirable way of preparing rice for food to reduce postprandial blood glucose and insulin responses and to improve colon health of humans.
      Practical Application

      After rice was cooked using different methods, including steamed, pilaf, and stir-fried, the stir-fried indica rice displayed the least starch hydrolysis rate and the largest resistant starch (RS) content. These results showed that cold storage of steamed normal rice at 4 °C for 24 h followed by stir-frying with corn oil (10%) reduced the rate of starch hydrolysis and increased the RS content. Ingesting stir-fried rice therefore can reduce the postprandial blood–glucose concentration and insulin response, which benefits the health of diabetics and prediabetics. The large RS content of the stir-fried normal rice could also provide health benefits to the colon."

      tatertot

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    4. Tatertot, I am intrigued by your line "RS preservation of cooking at high, dry heat vs. moist heat". I always microwave or bake my potatoes rather than steam. How does this preserve the RS? Thanks!

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    5. It has to with a property of starch known as starch hydrolysis. When starch granules are gently heated in a moist environment, the granules swell and burst, creating RDS (Rapidly Digestible Starch). This is the starch we know and love in bread, potatoes, rice, sweet potatoes, etc... It's what makes GI's very high.

      If you take a raw starch granule and heat it rapidly in a dry environment, it is frozen in time, so to say, it doesn't swell and burst but just gets hot and retains it's raw starch characteristics. In the case of potatoes and rice, the amylose starch granules turn into resistant starch and the amylopectin starch granules turn into SDS (slowly digestible starch) or RDS.

      In the case of sweet potatoes, squash, and other starchy veggies that are not high in RS, it's because of the type of starch or the physical characteristics of the starch that will not allow RS to form. In the case of potatoes, legumes, high-amylose corn, tapioca, and some rice, the starch is of the perfect design to be considered nearly pure RS in it's raw state and retain much of this if heated quickly in a dry environment.

      For these reasons, potato chips (US Style) have a very high RS content and boiled potatoes very low. Roasted potatoes are different from baked potatoes. To roast, you remove the skin, cut into smaller cubes and cook in high heat. Baked potatoes are usually made with the skin on or even wrapped in tin-foil, which in essence, merely steams them. Oven-fried french fries or french fries (fried in a healthy fat, of course) would have more RS than most baked potatoes by a factor of about 10.

      One way you can even the odds is to cook potatoes, rice, or beans by any means possible, then thoroughly chill (40 degrees for at least 24 hours--freezing even better) and reheat. Done this way, retrograded RS (RS3) forms in the cooling process and RS3 can withstand the temperatures of cooking as RS3 does not swell and burst like RS2 (naturally occuring starch).

      Here's a paper on RS3, abstract only--try to get the full text if you can. I have it, but on pdf and can't post it here. http://www.ncbi.nlm.nih.gov/pubmed/3812341

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    6. Very interesting. Thank you so much tatertot!

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    7. http://drbganimalpharm.blogspot.com/2013/09/feeding-microbiota-non-starch.html

      Really good blog series on gut microbes/RS

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  6. What are RS4 sources and what's the best time for ingesting them?

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    1. RS4 is synthetic and currently unobtainable (that I know of). Myotropics did make it via Thermicarb, but it has since disappeared.

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    2. Generation UCan makes a product called SuperStarch for athletic enhancements. I personally use Bob's Red Mill Potato Starch and Tapioca Starch in a 50/50 mix, 2-4TBS daily added to a smoothie, in addition to eating several RS-rich foods such as cold potatoes, green bananas, and dried plantain chips. Insulin sensitivity through the roof...sleep is great...stomach is as if made of cast iron now.

      Do a search on this site for resistant starch and/or gut microbes--lots written here!

      tatertot

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    3. Just wanted to add: My methods described above get you RS-2 and RS-3, not RS-4.

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    4. Haha I feel you. I always prefer my bananas slightly under-rippened, and I eat a pound of raw sweet potatoes daily! My gut never gets upset lol

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    5. I cut them up and dip them in yogurt or thermicarb or oatmeal or whatever. Think carrots except sweet potato.

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