|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)|
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)|
|Figure 2: Simplified schematic illustration of mechanism behind the EAA induced GLUT-4 increase in skeletal muscle (click here to learn more)|
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:
- 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...
- 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.
- 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)
- 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)|
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).
- 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.
- Baggio LL, Drucker DJ. Biology of incretins: GLP-1 and GIP. Gastroenterology. 2007 May;132(6):2131-57.
- 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
- 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.
- 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
- 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.
- 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.
- 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.