Phospholipid or Triglyceride? What's in Your Fish Oil Caps? Only Phospholipid Based DHA+EPA Reduces Fat Cell Growth & Elevated Insulin Levels Despite Obesogenic Diet

Image 1 (Liliyu. 2007): Look no further, DHA+EPA in phospholipid form can be found right around the corner in the salmon-sashimi at your favorite sushi restaurant, for example.

I guess you will already have heard about the "huge quality differences" of different fish oil products, the manufacturers of the more expensive products usually use to justify the price difference to the average no-name fish oil cap from your favorite bulk supplier. You may also remember a previous SuppVersity post on the obviously over-blown problem with oxidized (=rancid) fish oil (see "Some Things Fishy: Oxidized Fish Oil Totally Benign!?"), which - much to the researchers' own surprise, worked just as well as regular, fresh fish oil (Ottestad. 2011). What you will probably not have thought about before, however, is the triglyceride to phospholipid ratio of your fish oil caps (Note: While there are intact phospholipids in raw or barely cooked fish, it is almost certain that most of them are destroyed / damaged in the industrial production of fish oil from the waste products of the fishery industry).

Di- vs. triglyceride - One letter can make all the difference

In a recently published study, Rossmeisl et al. report that the administration of the exact same amount of n-3 polyunsaturated fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), either as tri- or diglyceride+pohosphate (as they are characeteristic for all phospholipids) had profoundly different effects on the amelioration of weight gain in a 9 week HFD overfeeding study and the reversal of obesity a second trial in which mice that had been subjected to an obesogenic high fat (+hypercaloric) diet for 4 months received chow that contained a dosage of 30g combined EPA + DHA per kg. With a food intake of ~65g per day and a mean body weight of ~30g (mid-trial) this yields the following rodent + human equivalent doses (HED, calculated for 80kg body weight) for the three treatment groups and two control groups in the overfeeding experiment:

• control - regular diet
• HFD - high fat diet (HFD) w/out supplement
• HFD+30TR - HFD + 0.16g/kg EPA+DHA from triglycerides; HED ~1g / day
• HFD+10PL - HFD + 0.05g/kg EPA+DHA from phospholipids; HED ~ 0.33g / day
• HFD+30PL - HFD + 0.16g/kg EPA+DHA from phospholipids; HED ~1g / day

Contrary to their identical ameliorative effects on diet induced weight gain, elevated plasma lipids and blood sugar levels, the triglyceride and phospholipid forms of DHA and EPA exerted very different effects on plasma insulin, adipocyte hypertrophy, hepatic steatosis (beginning NAFLD) and low-grade adipose tissue inflammation.

Figure 1: Body composition and glucose metabolism after 4 month HFD diet and subsequent 9 weeks of over-feeding on diets containing either no (control=100%) or 30g/kg diet DHA+EPA; data expressed relative to control (Rossmeisl. 2012)

As you can see in figure 1 only the phospholipid form of the n-3 polyunsaturated fatty acids reduced adipose tissue growth and hyperinsulinemia. And compared to the regular triglycerides, it also had much more pronounced effects on the accumulation of fat in the liver and the exuberant inflammation in the fat stores (WAT) of the animals.

A higher bioavailability of phosphate-bound EPA+DHA is probably only part of the story

Figure 2: Plasma, liver and white adipose tissue (WAT) levels of triglyceride (TL) and phospholipid varieties of DHA+EPA after 9 weeks on HFD diet with (w3TL or w3PL) or  w/out 30mg/kg chow DHA + EPA (Rossmeisl. 2012)

This is an interesting observation and the most straight forward explanation would actually be that due to their ability to be directly incorporated into the cell membrane the phosphate-bound lipids from the -PLI groups received would have a higher affinity to be incorporated into the liver and/or adipose tissue. And while the latter was not the case (cf. figure 2) the significantly more pronounced accumulation of omega-3 phospholipids in the liver of small critters, appears to confirm this hypothesis - or, as the Rossmeisl et al. put it:

Thus, the superior efficacy of dietary LCn-3 PUFA adminis-tered as phospholipids in terms of counteracting adverse effects of developing obesity was linked to the improved bioavailability of DHA and EPA, and to the accumulation of these fatty acids in phospholipids in metabolically relevant tissues.

If you take a closer look at the data, you will yet realize that the omega-3 content of the adipose tissue (WAT) is still pretty low. Other than in the liver, where the TG/PL ratio was significantly lower, when the animals received a phospholid enriched diet, the n3 concentrations were identical for both groups. A higher bioavailability alone could thus hardly explain the pronounced reduction in WAT inflammation and more importantly the ameliorative effect on adipocyte hypertrophy the researchers observed in the in reversal study.

Additional phospholipid advantage: Greater inhibitory effect on inflammatory ligand production

A closer analysis did yet reveal different / more pronounced downstream effects of the phospholipid treatment on the occurrence of the pro-inflammatory endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) and the production of their EPA and DHA derived anti-inflammatory counterparts N-eicosapentaenoylethanolamine (EPEA) and N-docosahexaenoylethanolamine (DHEA). The former, i.e. the reduction of 2AG had already been implicated as one of the fundamental mechanism behind the anti-inflammatory effects of krill oil by Batteta et al. in 2009 (Batteta. 2009) and does - despite its obvious efficacy raise some safety concerns, as the synthetic cannabinoid receptor 1 antagonist rimonabant, which has been used very effectively to treat obesity had to be withdrawn from clinical practice due to intolerable adverse psychiatric side effects (mostly anxiety and/or depression, cf. Moereira. 2009).

Fish is still your goto source for DHA & EPA, as trigs and phospholipids in their natural ratio!

Image 2 (animalcrossingdaily): The fishcow! Well, personally I prefer to eat fish and beef, but if you happen to hit upon one of those, I bet their DHA + EPA content is about as "monstrous" as their overall look ;-)

Whether high doses of phospholipid enriched fish oil, as they are suggested by Rossmeisel et al. as an adjunct "treatment strategy for obesity-associated disorders" that should be preferred over regular triglyceride or ethyl-ester (Lovazza) based n-3 PUFA supplements, due to their to higher bioavailability an efficiacy (Rossmeisl. 2012), would actually produce similar adverse effects is questionable. At dosages corresponding to those used in the study at hand, i.e. 1g per day(!), I would say that this is very unlikely. In view of the still prevalent advice of (pseudo-)experts to start out with at least 5g per day of EPA + DHA, I wouldn't be so sure, though, that we are not already seeing the first "victims" of scientifically unwarranted fish oil overconsumption and subsequent endocannabinoid imbalances complaining of anxiety and chronic fatigue on bulletin boards, where one of the "standard treatments" people will suggest is to "up your fish oil intake"...

For you, as a diligent student of the SuppVersity, active and healthy physical culturist, the results of this study do not really make a difference, anyway. After all, you have always been getting your weekly dose of omega-3 fatty acids from fish, the natural source of both the triglyceride and phospholipid form of DHA and EPA, and grass-fed beef or lamb (even grain-fed beef is a relatively good source of omega-3, by the way, only the ratio of omega-6 to omega-3 is usually higher; cf. Wood. 2004) - didn't you?

References:

1. Batetta B, Griinari M, Carta G, Murru E, Ligresti A, Cordeddu L, Giordano E, Sanna F, Bisogno T, Uda S, Collu M, Bruheim I, Di Marzo V, Banni S. Endocannabinoids may mediate the ability of (n-3) fatty acids to reduce ectopic fat and inflammatory mediators in obese Zucker rats. J Nutr. 2009
   Aug;139(8):1495-501.
2. Moreira FA, Crippa JA. The psychiatric side-effects of rimonabant. Rev Bras Psiquiatr. 2009 Jun;31(2):145-53. Review.
3. Ottestad I, Vogt G, Retterstøl K, Myhrstad MC, Haugen JE, Nilsson A, Ravn-Haren G, Nordvi B, Brønner KW, Andersen LF, Holven KB, Ulven SM. Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial. Br J Nutr. 2011 Dec 5:1-12.
4. Rossmeisl M, Macek Jilkova Z, Kuda O, Jelenik T, Medrikova D, Stankova B, Kristinsson B, Haraldsson GG, Svensen H, Stoknes I, Sjövall P, Magnusson Y, Balvers MG, Verhoeckx KC, Tvrzicka E, Bryhn M, Kopecky J. Metabolic Effects of n-3 PUFA as Phospholipids Are Superior to Triglycerides in Mice Fed a High-Fat Diet: Possible Role of Endocannabinoids. PLoS One. 2012;7(6):e38834. Epub 2012 Jun 11.  
5. Wood JD, Richardson RI, Nute GR, Fisher AV, Campo MM, Kasapidou E, Sheard PR, Enser M. Effects of fatty acids on meat quality: a review. Meat Sci. 2004 Jan;66(1):21-32.

Whey More Insulinogenic Than White Bread: Insulin Spike is Mediated by GIP Secretion in the Gut & Effect of EAAs on the Pancreas + Why Whey is Still the Better Choice

Image 1: Peter Czerwinski, aka Furious Pete, certainly did not care about the pro-insulinogenic effects of whey, when he ate 900g of it within 3:30min, click here to watch his record (Furios Pete, 2010)

Among muscle heads and physical culturists, alike, whey protein has become almost synonymous with building slabs of lean muscle.What many of the protein fans - especially the low carbers - tend to overlook or ignore, though, are the pro-insulinogenic effects of whey protein, in general, and purified whey protein isolates and hydrosolates, in particlar, which do not just augment the insulin release in response to carbohydrate ingestion (Morifuji. 2010), but exert a decent increase in pancreatic insulin release in and out of themselves (Claessens. 2009). Further evidence on the hitherto not yet fully understood mechanism behind the whey induced increase in insulin comes from a recently published paper by Albert Salehi and his colleagues from the Lund University in Sweden, the University of Copenhagen in Denmark and the Oxford Center for Diabetes, Endocrinology and Metabolism in the UK (Salehi. 2012).

Whey vs. white bread and human plasma as incubation medium

In the aforementioned paper, the scientists present the results of a combined in-vivo + in-vitro trial on the effects of glucose, amino acids and amino acids mixtures (as they are found in whey) on pancreatic insulin production and its relationship to the incretin response (release of incretin hormones from specialized cells in the small and large intenstine). To this ends, the researchers had their subjects, four men and two women (healthy non-smokers, normal-weight, age 20-30y), consume test meals containing either white bread (3.7g of protein) or whey (16.7g of protein), after an overnight fast, on two different occasions. The meals had to be consumed within 12 minutes and blood samples were taken 7.5,  15, 30 and 45 min after the start of the meal.

Figure 1: GIP and GLP-1 response to whey and white bread (left, top & bottom); insulin release (%) per islet relative to glucose after incubation with different amino acids, amino acid mixtures and mixture + GIP (Salehi. 2012)

As you can see in figure 1 (left), the ingestion of  ~20g of whey protein (containing 16.7g of protein + lacose + minimal amounts of fat) produced a significantly more pronounced in increase in glucose-dependent insolinotropic peptide (GIP, see previous post "Waxy Maize Reloaded" for more information) than the white bread meal. GIP is a hormone-like substance that is produced by the enteroendocrine cells of the gut lining, amplifies the glucose-induced production of insulin in the pancreas, slows down digestion, increases glucose absorption, ramps down fatty acid oxidation and sets you into energy "storage mode" - unfortunately in both forms, skeletal and liver glycogen and fat!

Figure 2: Simplified schematic illustration of mechanism behind the EAA induced GLUT-4 increase in skeletal muscle (click here to learn more)

GLUT-4 activation - another reason, why whey is way better than sugar: If you remember Monday's blogpost on the isolated effects of essential amino acids (EAAs) on the GLUT-4 (glucose transporter = the shuttle that carries glucose from the blood stream into the cell) expression on skeletal muscle cells, it is evident that contrary to sugar or most forms of carbohydrates, whey protein, or rather the essential amino acids in whey, cod, soy, beef, pea, egg and other high EAA protein sources exert nutrient-repartitioning effects due to selectively increasing insulin induced glucose uptake in skeletal muscle and constant glucose uptake in adipose tissue (Lavigne. 2001).

Against that background it is not surprising that the combined effects of GIP (figure 1, top-left) and the amino acid induced increase in insulin production (figure 1, right, orange) lead to a more than 7-fold increase (compared to glucose control) in pancreatic insulin production after incubation of mouse Langerhans cellls (the cells of the pnacreas that are responsible for insulin mediated glucose control) with sera containing a mixture of EAAs and GIP that was matched to the respective EAA and GIP concentrations in the preceding whey vs. white bread human experiment.

Don't worry there are also benefits that can compensate for the insulin spike

Now these results certainly seem odd, after all "the experts" say that insulin is the root cause of all evil! Now whey spikes insulin and GIP and still we see study after study popping up, reporting "beneficial effects" of whey protein on glucose metabolism and overall health - how can that be? The reasons are manifold and actually quite straight forward:

1. Insulin is not the devil - Contrary to common believe the problem is not insulin, but insulin resistance and overspilling glucose stores. If your insulin spikes and you are not insulin resistant, the cells will suck up glucose, your blood sugar will drop and your insulin will drop as well; so, in terms of negative side effects, the most obvious one would be postprandial hypoglycemia in response to large boluses of whey protein (and even that is usually compensated for by increases in glucagon and consequently gluconeogensis)  - that the latter can have long-term detrimental effects on insulin sensitivity is a whole other issue, though...
2. Many studies use (pre-)diabetic subjects - In a pre-diabetics an increase in insulin release due to whey will improve postprandial glycemia and must thus be considered beneficial - it's "nature's insulin supplement", if you will, and particular helpful for non-insulin-dependent type-II-diabetics.
3. Effects on skeletal muscle are neglected - Anything that can potentially help build and maintain muscle tissue (and we all know whey can do that) will help with glycemia, obesity and lipid metabolism, because the increase or (esp. in the elderly) maintenance of skeletal muscle mass ("Metabolic Currency" - Carl Lanore) will allow for greater intra-muscular glucose stores and fatty acid oxidation (assuming you are still insulin sensitive, cf. 1)
4. The "satiety hormones" are overlooked - Similar to the muscle building effects, the increase in GLP-1, a hormone which is by no means just responsible for inducing satiety (read all about GLP-1 in my previous post "Eat More, Burn More and Lose Fat Like on Crack With GLP-1") have been hitherto largely ignored. And that despite the fact that increases in GLP-1 could be among the main reasons that whey and other EAA-rich protein sources have repeatedly been shown to help weight- and, more importantly,  fat loss and increase metabolic health (Ranganath. 1996; Baggio. 2007; Akhavan. 2011; Gerspach . 2011). 

Image 2: Real foods are better protein choices for the last weeks of a contest prep (image directly from Adelfo Cerame's kitchen)

In other words, while some of the "beneficial effects" in obese and insulin resistant individuals could actually turn against lean, active individuals, the muscle-building and "satiety hormone" induced metabolic effects make up for the potential fat storage in scenarios of energy overconsumption (remember: there is a certain margin of carloric surplus, where the laws of thermodynamics do apply, cf. "A Tale of Macro- and Micronutrient Modifications")

Whey is probably not your best choice for the final weeks of a contest prep, though

Still, if you are in the final phase of prepping for a contest and want that "paper-thin" skin conditioning, like our common friend Adelfo Cerame does, real-food protein sources like chicken, fish, lean meat etc. should be your main sources and protein shakes, an exclusive post-workout thing (in the last days, maybe not even that).

References:

1. Akhavan T, Luhovyy BL, Anderson GH. Effect of drinking compared with eating sugars or whey protein on short-term appetite and food intake. Int J Obes (Lond). 2011 Apr;35(4):562-9. Epub 2010 Aug 24.
2. Baggio LL, Drucker DJ. Biology of incretins: GLP-1 and GIP. Gastroenterology. 2007 May;132(6):2131-57.
3. Claessens M, Calame W, Siemensma AD, van Baak MA, Saris WH. The effect of different protein hydrolysate/carbohydrate mixtures on postprandial glucagon and insulin responses in healthy subjects. Eur J Clin Nutr. 2009 Jan;63(1):48-56. Epub 2007 Sep 12
4. Gerspach AC, Steinert RE, Schönenberger L, Graber-Maier A, Beglinger C. The role of the gut sweet taste receptor in regulating GLP-1, PYY, and CCK release in humans. Am J Physiol Endocrinol Metab. 2011 Aug;301(2):E317-25. 
5. Lavigne C, Tremblay F, Asselin G, Jacques H, Marette A. 2001. Prevention of skeletal muscle insulin resistance by dietary cod protein in high fat-fed rats. Am. J. Physiol. Endocrinol. Metab. 281:E62–71
6. Morifuji M, Ishizaka M, Baba S, Fukuda K, Matsumoto H, Koga J, Kanegae M, Higuchi M. Comparison of different sources and degrees of hydrolysis of dietary protein: effect on plasma amino acids, dipeptides, and insulin responses in human subjects. J Agric Food Chem. 2010 Aug 11;58(15):8788-97.
7. Ranganath LR, Beety JM, Morgan LM, Wright JW, Howland R, Marks V. Attenuated GLP-1 secretion in obesity: cause or consequence? Gut. 1996 Jun;38(6):916-9. 
8. Salehi A, Gunnerud U, Muhammed SJ, Ostman E, Holst JJ, Björck I, Rorsman P. The insulinogenic effect of whey protein is partially mediated by a direct effect of amino acids and GIP on beta-cells. Nutr Metab (Lond). 2012 May 30;9(1):48.

"20g or 40g of Whey?" That's the Wrong Question, When 4-5x 20-25g from Different Sources Would be the Answer!

Image 1: There could be a reason that your favorite protein powder comes with a scoop and a suggested serving size of 25-30g protein (max.)

If you could just pick one dietary supplement to take to desert island, what would it be? Creatine? Unquestionably a good choice. Yet even if the local fauna provided you with unlimited amounts of eggs, meats and fish, a whey protein powder, or I should say a leucine-rich complete protein source would probably be a better choice. Despite the fact that I am still skeptical as far as the real world significance of supplementally augmented post-exercise increases in fractional protein synthesis as the main, let alone exclusive determinant of skeletal muscle hypertrophy is concerned, it is undebatable that the delicate balance between protein breakdown and synthesis is at least the most obvious and, in the short term, probably in fact the most influential contributor to muscle growth.

"Only 1.2 - 1.6 protein per kg/day!?" - Calm down! The total amount is not all that counts

According to the latest installment of the "A to Z of Nutritional Supplements" series in the British Journal of Sports Medicine (the part on protein was - you may already have guessed it - co-authored by no one else but Stuart Phillips) the "current scientific evidence" suggests that

1. daily intakes higher than the RDA, to be precise, 1.2-1.6g/kg body weight,
2. an emphasis on leucine-rich protein sources (I suggest dairy, alternatively pea protein),
3. multiple servings of 20-25g of protein / protein-rich foods spread equally across the day,
4. an additional protein shake immediately after your workout

"should be very effective at allowing repair, remodelling and adaptation, and gains in lean mass in athletes" (Phillips. 2012).

Quality, Consistency and frequency over gluttony

For an 80kg athlete this would translate into a total protein intake of 96-128g of protein per day. Sounds pretty sparse, right? Well, if we just count proteins from meats, eggs, fish, dairy and dietary supplements and discard the protein from other sources, this would leave our 80kg athlete with max. 4-5 meals at which he would easily achieve the "threshold" limit of 25g; five opportunities to monetize on the dietary induced increase in protein synthesis; and five potentially protein anabolic spikes in plasma amino acid concentrations.

Remember: In the slowly abating hoopla around leucine people tend to overlook that despite its ability to set the protein synthetic machinery into gear, leucine needs the other EAAs and conditionally essential amino acids to get its muscle building job done.

And though the actual data does not provide any revolutionary new insights into the "ideal" amount of protein, a recently published study from Kevin D. Tiptons group at the University of Birmingham provides further evidence that everyone who strives to maximize skeletal muscle protein synthesis should be primarily concerned about the consistent and frequent (3) ingestion of quality (2) protein (Jackman. 2012).

Figure 1: Urea production (µmol/h/kg * 4h) and fractional myofibrillar protein synthesis (per hour) in the 4-hour recovery period after an intense leg workout and supplementation with either 20g or 40g of whey protein (data based on Jackman. 2012)

Despite the fact that there was a greater increase in fractional myofibrillar protein synthesis after the ingestion of 40g vs. 20g of whey protein after the 8 sets of 10 repetitions of leg presses and leg extensions the 30 previously resistance trained male subjects in the Jackman study had to perform, the +10% difference (+51% increase in MPS in the WP40, +41% in the WP20 group; increase expressed vs. placebo), the latter did not reach statistical significance over the 4h post workout period.

Diminishing returns with large vs. multiple bolus ingestions

Contrary to previous studies investigating the differential response to different amounts of dietary protein in the vicinity of a strength workout (cf. "Protein Synthesis Beyond the 20g Limit"), in which the subjects often trained in a fasted state, the Jackman study also confirms that the profound beneficial effects of immediate protein supplementation are retained, even if the last "protein rich meal" was consumed "only" 3h before the workout.

Figure 2: Experimental protocol of the Jackman study (based on Jackman. 2012)

This beneficial effect of repeated protein ingestion / protein timing stands in line with with the observation that Jackman et al. observed peak amino acid concentrations in the WP20 and WP40 arm of their study 15-30min and 45-60min after the ingestion of the respective amount of whey protein. From the fact that the latter went hand in hand with a statistically significant increase in insulin concentrations and +25% greater urea production in the WP40 trial, we can assume that a non-significant amount of the additional 20g of protein of the 40g whey protein shake was "abused" for gluconeogenesis instead of getting stored within the muscle tissue.

Image 2: The results Adelfo saw from the consistent intake of a perfectly timed mixture of fast and slow digesting proteins speak for themselves - intermittent fasting or not, consistency and frequency are key!

So, even if you don't care about "wasting" dietary protein, you better make sure to distribute your protein intake evenly within your "feeding window", with 20-25g of fast-digesting protein like whey every 2-3h, or a combination of fast digesting and slow digesting proteins (like whey + casein, or whey alone followed by a complete meal) every 3-4h to maintain a decently high and thusly "pro anabolic" level of amino acids in your blood stream while avoiding the hyperinsulinemic effects of larger boluses of whey protein. And if you don't think that this will work, or would be incompatible with the Intermittent Fasting protocol you have taken up as of late, I suggest you go through Adelfo Cerame's contest prep diet again, because with the lions share of his protein intake coming from very slow digesting "real food" protein sources (specifically meats and casein from cottage cheese and raw milk, cf. "3.2kg of Lean Mass With 40g of Casein Pre-Bed"), he strategically spiked with whey protein in the vicinity of his workouts - Adelfo achieved just that: a decent level of hyperaminoacidemia (=elevated serum amino acids) to make optimal use of the "24h Barn Door of Opportunity".

True or False? Adding Fat to A Carby Meal Lowers Insulin Response. Muscle Hypertrophy Impairs Oxygen Diffusion. Reducing Carb Intake Improve Muscular Insulin Sensitivity

Will the additional butter on top of the potatoes reduce the insulin response? You can find the answer to this and the other questions in today's episode of "True or False?"

If you are a regular here at the SuppVersity you should by now recognize the "True or False" part of the headline of today's SuppVersity article. Therefore it's probably unnecessary to say this explicitly, but this is a new series, where I could use a little help from your side. Well, ... I should say, I believe it would become even more fun, if you lend me a hand and send me short pieces of wisdom or idiocy like "Adding fat to a carby meal reduces the insulin response"  you deem worthy of being addressed in the True or False series. I cannot, or rather will not promise that I will address each and every of your suggestions, but if it interests me and can be tackled in a 2-3 paragraph text, your chances ain't bad to get your suggestions dealt with - if you got any ideas, just post them in the comment section of one of the previous installments (including today's, obviously).

Adding Fat to A Meal Will Ameliorate the Insulin Response

False. When you are browsing the Internet it is easy to get the impression that what is wrong or right is not determined by scientific evidence, but by the number of people who repeat it in their blogs, on their facebook walls and in their bulletin board contributions. The common "wisdom" that it would be a good idea to add some fat to a meal to reduce the insulin spike it will give you is one of those paradigms that remain intrinsically flawed no matter how often they are repeated.

Figure 1: Althoug the glucose AUC drops after the addition of fat (slowed absorption of glucose from the intestine), the amount of insulin (2ndary axis) that is needed to stash the glucose away is 8.5x higher (on a per unit base; cf. violet bar) and the absolute insulin response does not decrease at all in lean healthy men and women (Collier. 1983)

If you do take a look at what actually happens, when you add fat to a meal, it is yet not difficult to understand how that myth came about. Just like people don't understand that the GI of a certain carbohydrate source doesn't tell you much about it's effect on insulin, the fact that the addition of fat ameliorates the postprandial spike in glucose gets misinterpreted as "fatty meals are less insulinogenic than low fat meals". In fact, the addition of 50g of butter on top of the 50g of carbohydrates the 8 lean, weight stable men and women (N=4, each) consumed in form of potatoes, did not have any effect on the post-prandial insulin release at all.

GIP Or Not GIP - That is the Question: "Fat intake, in addition to ingestion of carbohydrate, stimulates GIP release. Therefore, during a mixed meal GIP might act to promote the storage of both triglyceride and glucose indirectly via the release of insulin." (Kieffer. 2003)

The amount of the fat storage peptide GIP (learn more), on the . Therefore, Collier and O'Dea are 100% right, when they state in the conclusion of their 1983 paper that...

"despite the apparent improvement in glucose tolerance when carbohydrate is ingested together with fat, the accompanying potentiation of insulin secretion could form the basis of long-term changes in insulin sensitivity which accompany alterations in dietary fat intake." (Collier. 1983)

You may want to remember that, whenever you feel inclined to add a ton of bacon on top of your sweet potatoes in the false believe that this would "mitigate" the effects of the carb-laden tubers the insulin response.

This obviously does not change the fact that having some fat in a meal does have the added benefit of increasing GLP-1 and PYY levels and thus contributing to a longer satiety effect (eg. Knut. 2008)

 Skeletal Muscle Hypertrophy Impairs Oxygen Diffusion

"Some HIIT For Life & Less LISS For More!" As the study at hand shows, this mantra is all the more important for the more muscular SuppVersity readers - that does not change that exercising longer to burn more fat won't work for anyone, muscular or not (learn why).

True! Contrary to the previous myth about the beneficial effects of adding fat to a high carb meal, which was not just totally messed up, but also pretty well-known the physical necessity that marked skeletal muscle hypertrophy will have a negative effect on he O2 diffusion of the "balooned up" musculature is something I would guess few of you have ever heard about before.

I have to admit that the 15-20% reduction in maximal oxygen consumption per kg of quadriceps mass a group of researchers from the University of Udine observed in 11 young athletes with marked skeletal muscle hypertrophy induced by long-term resistance training (body mass ~103kg), when they compared their them to 11 normal controls (body mass ~77kg) looks scary at first.

If you do yet also take into consideration that this decrease in oxygenation was accompanying improvements in ADP-stimulated mitochondrial respiration (+59%; takes place, when the ATP stores are used up) and a tighter coupling of oxidative phosphorylation, it becomes evident that the training induced enhancements in mitochondrial respiration seem to compensate for the hypertrophy-induced impaired peripheral O₂ diffusion.

"The net results are an enhanced whole body oxidative function at peak exercise, and unchanged efficiency and O₂ cost at submaximal exercise, despite a much greater body mass." (Salvadego. 2013)

In other words, despite "suboptimal" oxygenation of the musculature a bigger metabolic engine will still burn more fat... but only when it's working at peak intensity. It won't do so at submaximal intensities, where the O2 costs are "identical" (statistically). So, what does that tell us about the usefulness of training in the non-existent fat burning zone for advanced, heavily muscled trainees? Yep, it's even smaller than for the average sedentary housewife.

Low Carb High Fat Diets Lead to Acute Improvements in Muscular Insulin Sensitivity

False. Although the slowly abating low-carb craze does still make it appear as if "just eating less carbs" was the solution to everything, it is only logical that low carb dieting leads to changes in skeletal muscle insulin signaling, i.e. decreases in insulin-stimulated tyrosine phosphorylation of IRS-1 and PI3-kinase activity, which reduce, not increase the ability / willingness of the musculature to suck up glucose from the blood stream within no more than 5 days (cf. Pessin. 2000; Reusch. 2002).

Figure 2: Changes (before vs. after 5-day intervention) in fasting glycemia and lipidemia and glucose rate of appearance and disposal during euglycemic clamp conditions (Wang. 2013)

So even in the absence of significant effects on the body composition or signs of full-blown whole body  insulin resistance, the changes Cecilia C.L. Wang and colleagues observed in muscle samples that were taken from their insulin tolerant, but overweight subjects are identical to those you would observe in the early stages of diabetes, and do thus predate "changes in whole body insulin sensitivity" (Wang. 2013).

"But that ain't low carb!" Certainly a valid critism w/30% carbs and 20% protein in the diet it is practically impossible to reach ketosis, but - believe it or not - this is representative of the "low carb" diets you will usually see in the pertinent literature.

Wang et al. base their conclusion on the results of a recently conducted weight loss intervention that involved 18 obese individuals without diabetes who underwent euglycemic-hyperinsulinemic clamp and skeletal muscle biopsy after:

• 5 days of eucaloric diet (30% fat, 50% carbohydrate), and 

• 5 days of a 30% calorie-restricted diet, containing either...

• LF/HC: 20% fat, 60% carbs
• HF/LC: 50% fat, 30% carbs.

As mentioned in the introduction it's only logical and not necessary a bad thing that the skeletal muscle of the LF/HC group reacted with favorable changes in inulin receptor phosphorylation and lead to improvements in the IRS-1-associated PI3-kinase activity, which also figures in the exercise and nutrient induced increase in skeletal muscle protein synthesis (its among others the main target of IGF-1, of which keto dieters are known to have significantly reduced levels, anyway; cf. Fraser. 2000; Glass. 2003).

In other words, "No, 'just eat no carbs' is not the solution to everything", but will lead to certain metabolic adaptations which are not exactly conducive to returning to a normal carb diet afterwards. Plus, if you are a lean gymrat striving to to maximize your lean mass gains the full-blown hepatic growth hormone resistance and corresponding -50% drop in hepatic IGF-1 mRNA expression Bielohuby et al. observed in a rodent model of ketogenic dieting in 2011 probably won't come handy in the long run (on a side note: The "keto rodents", with their 92.8% fat diet also had a 5% reduction in lean mass and 46%, 56% and 223% higher relative amounts of visceral fat in the inguinal, epididymal and perirenal fat pads; cf. Bielohub. 2011)

Keep in mind this is a physiological form of insulin resistance

Learn how Adelfo lost his carbophobia and saw nothing but benefits from it (read more). That someone in the >30kg/m² BMI region with type II diabetes should keep a close eye on carb intake is a whole different story.

That being said, it is at least in part due to this mechanism that this type of diet works so well for highly insulin resistant individuals. It does not require the body to become insulin sensitive to work, but provides your body with a substrate that would - in and out of itself - require a certain degree of insulin resistance to make sure your muscle don't suck away the little glucose that's floating around and make you feel miserable and hypoglycemic. That you cannot observe those changes with a glucometer at home should be obvious. After all you are not eating carbs, are you?

Would the effect have been different with a true keto diet? The weight loss? Maybe. The transient insulin resistance? More pronounced, if anything. If you are already obese and freakin' insulin resistant to begin with, this does yet hardly matter. Low fat, high fat, keto - I don't care! The weight loss, the ensuing reduction in chronic inflammation and the new room to actually stash away superfluous energy alone will sooner or later also help you to reduce your insulin resistance.

Suggested read on physiological (=adaptation to diet / exercise) insulin resistance: "The Marathon Paradox - How Temporary Exercise-Induced Insulin Resistance Paves the Way for Fat Burning Machines" (complete article)


References:

• Berk ES, Kovera AJ, Boozer CN, Pi-Sunyer FX, Johnson JA, Albu JB. Adiponectin levels during low- and high-fat eucaloric diets in lean and obese women. Obes Res. 2005 Sep;13(9):1566-71.
• Bielohuby M, Sawitzky M, Stoehr BJ, Stock P, Menhofer D, Ebensing S, Bjerre M, Frystyk J, Binder G, Strasburger C, Wu Z, Christ B, Hoeflich A, Bidlingmaier M. Lack of dietary carbohydrates induces hepatic growth hormone (GH) resistance in rats. Endocrinology. 2011 May;152(5):1948-60.
• Collier G, O'Dea K. The effect of coingestion of fat on the glucose, insulin, and gastric inhibitory polypeptide responses to carbohydrate and protein. Am J Clin Nutr. 1983 Jun;37(6):941-4.
• Fraser DA, Thoen J, Bondhus S, Haugen M, Reseland JE, Djøseland O, Førre O, Kjeldsen-Kragh J. Reduction in serum leptin and IGF-1 but preserved T-lymphocyte numbers and activation after a ketogenic diet in rheumatoid arthritis patients. Clin Exp Rheumatol. 2000 Mar-Apr;18(2):209-14.
• Glass DJ. Molecular mechanisms modulating muscle mass. Trends Mol Med. 2003 Aug;9(8):344-50. Review.
• Kieffer TJ. GIP or not GIP? That is the question. Trends Pharmacol Sci. 2003 Mar;24(3):110-2.
• Knuth ND, Shrivastava CR, Horowitz JF. Reducing dietary fat from a meal increases the bioavailability of exogenous carbohydrate without altering plasma glucose concentration. J Appl Physiol. 2009 Jan;106(1):122-9. doi: 10.1152/japplphysiol.90404.2008. Epub 2008 Nov 13. 
• Pessin JE, Saltiel AR. Signaling pathways in insulin action:molecular targets of insulin resistance. J Clin Invest. 2000;106(2):165–9.
• Salvadego D, Domenis R, Lazzer S, Porcelli S, Rittweger J, Rizzo G, Mavelli I, Simunic B, Pisot R, Grassi B. Skeletal muscle oxidative function in vivo and ex vivo in athletes with marked hypertrophy from resistance training. J Appl Physiol. 2013 Mar 21.
• Reusch JE. Current concepts in insulin resistance, type 2 diabetes mellitus, and the metabolic syndrome. Am J Cardiol. 2002;90(5A):19G–26G.
• Wang CC, Adochio RL, Leitner JW, Abeyta IM, Draznin B, Cornier MA. Acute effects of different diet compositions on skeletal muscle insulin signalling in obese individuals during caloric restriction. Metabolism. 2013; 62:595–603

Biotin Ameliorates Skeletal Muscle Insulin Resistance in Model of Type II Diabetes. Increase in GLUT-4 Expression Yet not Accompanied by Translocation to Cell-Membrane

Image 1: Otsuka Long-Evans Tokushima fatty rats (OLETF, right) have the genetical disposition to become type II diabetics.

Are your nails brittle? Is your hair falling out? No? Then, are you obese or insulin resistant? Yes? ... I guess, by know you are asking yourselves what your hair and nails have to do with your pre-diabetic beer-belly. Well, according to the recently published restults from a study by Yuka Saki and his Japanese colleagues, biotin, the water-soluble nutrient that has been discovered by Bateman in 1916 and is also known as vitamin B7, vitamin H or coenzyme R could well be the missing link. After all, the well-known, but often misunderstood micronutrient plays a central role in both fatty acid, as well as glucose metabolism and is by no means just a "hair & nails" vitamin.

Biotin could help even if "it's in your genes" ;-)

The Japanese researchers used the infamous Otsuka Long-Evans Tokushima fatty rats whose name already implies that their have the unfortunate propensity to gain tons of body fat and develop type II diabetes, even if they are not fed the "high fat" diet (of which at least those of you who are not the first time here at the SuppVersity should know by now that it is high in fat and carbs) to check, whether supplementation could ameliorate the inevitable development of skeletal muscle insulin resistance in these poor critters.

Figure 1: Body weight, fasting glucose and insulin levels at the beginning and end of the 8-week study period (data adapted from Sasaki. 2012)

If you look at the results of the 8 week treatment period in the course of which the 34-week old, already overweight (compared to the non-diabetic LETO group) OLETF rats received either plain water or water with 3.3mg/L biotin (i.e. ~400µg/kg biotin for a rat and 65µg/kg for a human being), the treatment did in fact have the desired effect on glucose and insulin levels (cf. figure 1). The increase in insulin sensitivity, on the other hand, "allowed" the biotin-treated OLETF rats to gain even more weight than their profoundly diabetic peers. This, by the way, is something you will also see in humans, who - just as their omniscient Dr. told them - take their diabetic drugs and / or insulin, but refuse to make the necessary dietary and lifestyle changes.

Figure 2: Glucose uptake, total and membrane GLUT-4 expression in hindlimb muscle of 42-week old OLETF rats with or without biotin treatment (data calculated based on Sasaki. 2012 and expressed relative to non-diabetic LETO control)

What is also interesting is that despite a significant increase in total GLUT-4 (glucose transporter) expression in the skeletal muscle of the OLETF rats, a concomitant increase in receptor translocation to the cell-membrane, of which you have probably read in previous blogposts that it is responsible for the exercise-induced increase in glucose uptake, did not take place (cf. figure 2). Consequently, the glucose uptake in the hindlimb muscle did increase in response to biotin supplementation, but failed to reach the same (100% in figure 2) level as in the non-diabetic control group.

Biotin does not via AMPK... good or bad news?

These observations lead the scientists to conclude that the mechanism that is responsible for the nevertheless beneficial effects of supplemental biotin can not be a direct consequence of AMPK activation, which is at the heart of both exercise, as well as drug (esp. Metformin) induced ameliorations in insulin sensitivity. This is something, I actually find pretty interesting, because a) the elucidation of the exact mechanism by which biotin is able to increase insulin sensitivity and skeletal muscle glucose uptake could lead to novel insights into skeletal muscle glucose metabolism which could also be of relevance for "physical culturists", and b) if biotin, despite being essential for the activation of Acetyl-CoA carboxylase (ACC), a major downstream target of AMPK, does not work by "simply" stimulating the AMPK pathway, it is actually likely that the effects of biotin supplementation and exercise could add up.