Soy protein supplementation increases serum insulin-like growth factor-I in young and old men but does not affect markers of bone metabolism.
Summary from Pubmed - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=12221217&query_hl=1&itool=pubmed_docsum
Full Text - http://jn.nutrition.org/cgi/content/full/132/9/2605
Summary from Pubmed - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=15941900
Full Text - http://www.ajcn.org/cgi/content/full/81/6/1442
Question
Would this not suggest that 30g+ of dairy proteins deserve a place in a weightlifters daily diet to raise *IGF-1 levels? Or would the increase (30-68% suggested in articles/video) not be great enough to aid hypertrophy and (dare I say) hyperplasia?
*Given that the vast majority is bound, of course.
Am I taking 1+1 and getting 3? :blink:
Thanks.
Summary from Pubmed - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=12221217&query_hl=1&itool=pubmed_docsum
Full Text - http://jn.nutrition.org/cgi/content/full/132/9/2605
Effect of protein supplementation during a 6-mo strength and conditioning program on insulin-like growth factor I and markers of bone turnover in young adults.Recent studies suggest that soy protein (SP) protects bone in women; however, its effects on bone metabolism in men have not been investigated. Healthy men (59.2 +/- 17.6 y) were assigned to consume 40 g of either SP or milk-based protein (MP) daily for 3 mo in a double-blind, randomized, controlled, parallel design. Serum insulin-like growth factor-I (IGF-I), which is associated with higher rates of bone formation, was greater (P < 0.01) in men supplemented with SP than in those consuming MP. Serum alkaline phosphatase and bone-specific alkaline phosphatase activities, markers of bone formation, and urinary deoxypyridinoline excretion, a specific marker of bone resorption, were not different between the SP and MP groups. Furthermore, because substantial reductions in bone density occur in men at approximately 65 y of age, data were analyzed separately for men >/=65 y and those <65 y of age. The response to protein supplementation was consistent in the two age groups. The effects of SP on serum IGF-I levels suggest that SP may positively influence bone in men. Longer-duration studies examining the effects of SP or its isoflavones on bone turnover and bone mineral density and content in men are warranted.
Summary from Pubmed - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=15941900
Full Text - http://www.ajcn.org/cgi/content/full/81/6/1442
Also a video of Dr.John McDougall discussing soy proteins and IGF-1 from youtube - YouTube - Broadcast Yourself.BACKGROUND: Exercise is beneficial for bone when adequate nutrition is provided. The role of protein consumption in bone health, however, is controversial.
OBJECTIVE: The objective was to ascertain the effect of high protein intake on insulin-like growth factor I (IGF-I) and markers of bone turnover during 6 mo of exercise training.
DESIGN: Fifty-one subjects aged 18-25 y (28 men, 23 women) received a protein supplement (42 g protein, 24 g carbohydrate, 2 g fat) or a carbohydrate supplement (70 g carbohydrate) twice daily. Exercise consisted of alternating resistance training and running 5 times/wk. Plasma concentrations of IGF-I, insulin-like growth factor-binding protein 3, serum bone alkaline phosphatase, and urinary N-telopeptide collagen crosslink (NTx) concentrations were measured at 0, 3, and 6 mo after 24 h without exercise and a 12-h fast.
RESULTS: Three-day diet records indicated no difference in energy intake between the groups. Average protein intakes after supplementation began in the protein and carbohydrate groups were 2.2 +/- 0.1 and 1.1 +/- 0.1 g/kg, respectively (P < 0.001). The increase in plasma IGF-I was greater in the protein group than in the carbohydrate group (time x supplement interaction, P = 0.01). There were no significant changes over time or significant differences by supplement in plasma insulin-like growth factor-binding protein 3 (44 and 40 kDa). Serum bone alkaline phosphatase increased significantly over time (P = 0.04) and tended to be higher in the protein group than in the carbohydrate group (P = 0.06). NTx concentrations changed over time (time and time squared; P < 0.01 for both) and were greater in the protein group than in the carbohydrate group (P = 0.04). Men had higher NTx concentrations than did women (74.6 +/- 3.4 and 60.0 +/- 3.8 nmol/mmol creatinine; P = 0.005).
CONCLUSION: Protein supplementation during a strength and conditioning program resulted in changes in IGF-I concentrations.
Question
Would this not suggest that 30g+ of dairy proteins deserve a place in a weightlifters daily diet to raise *IGF-1 levels? Or would the increase (30-68% suggested in articles/video) not be great enough to aid hypertrophy and (dare I say) hyperplasia?
*Given that the vast majority is bound, of course.
Am I taking 1+1 and getting 3? :blink:
Thanks.