Fish protein supplementation: A little goes a long way
What is so particularly stunning about the data from the 8-week double-blinded cod protein supplementation trial Linn A. Vikøren and her colleagues conducted were not so much the results,
- a decrease in postprandial blood glucose AUC,
- more pronounced, yet less sustained insulin responses (sign of increases insulin sensitivity),
- a decrease in C-reactive peptide (CRP) levels, and
- reduced LDL cholesterol, as well as
- increases in lean muscle mass, and
- decreases in fat mass,
The whole is mostly way more than just the sum of its parts
If we go simply by the protein content that previous studies, such as , even the large dose, i.e. the 6g of cod protein isolate per day, the subjects received in the 2nd month of the intervention period, equals no more than
*Please keep in mind that Pilon et al. observed differences with respect to the physiological effects of fish proteins from different sources. In their rodent study, only salmon, yet not bonito, herring or mackerel protein had ameliorative effects on body weight and visceral body fat gain in rodents on a high-fat diet (Pilon. 2011)
- 20g of tuna
- 21g anchovies
- 22g salmon or halibut
- 23g snapper or tilapia
|Figure 1: Comparison of amino acid concentration (g/kg) of fish and whey protein (data for fish and whey from Vikøren. 2012 and Engelen. 2012, respectively)|
Reminder: Just in case you have forgotten about the SuppVersity news from Friday, May 4th, 2012, I suggest you briefly go back and read up on how "Cod Protein Promotes Muscle Repair After Injury More than Casein or Peanut Protein"
What is it about fish protein that makes it so potent - arginine, taurine, or synergistic effects?
As a regular, here at the SuppVersity, you will also know that there exists a fairly decent amount of research on potential and scientifically established health effects of arginine and taurine. Whether those two individual amino acids or rather synergistic effects due to the specific protein / peptide structure of cod proteins are able to explain any of the observed health benefits (see bullet points 1-4) or the changes in body composition (see bullet points 5-6 and figure 2, below) remains yet to be elucidated.
|Figure 2: Macronutrient composition of the diets at baseline, after 4 weeks and 8 weeks and changes in body composition compared to baseline (Vikøre. 2012)|
So what? Are fish protein isolates, the better whey?
Now without knowing the exact physiological mechanism behind the the observed effects on glucose and lipid metabolism and body composition of the 16 male and 19 female study participants, which could, as Vikoren et al. rightly point be a result of either the
- specific amino acid profile,
- the presence or formation of specific peptides (protein bonds), or
- as of yet unknown bioactive components of fish/cod protein,
In view of the results of previous studies by by Zhang etl al. (1993), Shukla et al. (2006), and specifically van Post-Skagagard et al. (2006) on the health effects of supplemental cod protein, it may yet be prudent to make another switch in your dietary / supplement regimen, namely one from fish oils to whole fish, which has already been shown to produce superior weight-loss and health effects than supplemental fish oil (e.g. Gunnarsdotti. 2008) - results of which we know by know that they well be mediated by the synergistic effects of oil and protein from whole fish.
- Daniells S. Low-cost, fat-free fish protein facility gets go ahead. Nutraingredients-usa.com. May, 27 2011. < http://www.nutraingredients-usa.com/Industry/Low-cost-fat-free-fish-protein-facility-gets-go-ahead >
- Engelen MP, Rutten EP, De Castro CL, Wouters EF, Schols AM, Deutz NE. Casein protein results in higher prandial and exercise induced whole body protein anabolism than whey protein in Chronic Obstructive Pulmonary Disease. Metabolism. 2012 Apr 16.
- Gunnarsdottir I, Tomasson H, Kiely M, Martinéz JA, Bandarra NM, Morais MG, Thorsdottir I. Inclusion of fish or fish oil in weight-loss diets for young adults: effects on blood lipids. Int J Obes (Lond). 2008 Jul;32(7):1105-12. Epub 2008 May 20.
- Lavigne C, Tremblay F, Asselin G, Jacques H, Marette A. Prevention of skeletal muscle insulin resistance by dietary cod protein in high fat-fed rats. Am J Physiol Endocrinol Metab. 2001 Jul;281(1):E62-71.
- Pilon G, Ruzzin J, Rioux LE, Lavigne C, White PJ, Frøyland L, Jacques H, Bryl P, Beaulieu L, Marette A. Differential effects of various fish proteins in altering body weight, adiposity, inflammatory status, and insulin sensitivity in high-fat-fed rats. Metabolism. 2011 Aug;60(8):1122-30.
- von Post-Skagegård M, Vessby B, Karlström B. Glucose and insulin responses in healthy women after intake of composite meals containing cod-, milk-, and soy protein. Eur J Clin Nutr. 2006 Aug;60(8):949-54.
- Shukla A, Bettzieche A, Hirche F, Brandsch C, Stangl GI, Eder K. Dietary fish protein alters blood lipid concentrations and hepatic genes involved in cholesterol homeostasis in the rat model. Br J Nutr. 2006 Oct;96(4):674-82.
- Vikøren LA, Nygård OK, Lied E, Rostrup E, Gudbrandsen OA. A randomised study on the effects of fish protein supplement on glucose tolerance, lipids and body composition in overweight adults. Br J Nutr. 2012 May 31:1-10.