Soy/Milk Protein Supplementation and IGF-1 Stimulation

Ziricote

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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
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.
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.
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
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.
Also a video of Dr.John McDougall discussing soy proteins and IGF-1 from youtube - YouTube - Broadcast Yourself.


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.
 
TeamSavage

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The effect-size is pretty small in the second study. But if I'm reading the figures correctly, the effect-size was damn large in the first study: a ~40-80% increase in IGF-1 for those taking soy. Surprising.
 
Werewolf

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You need to be a little careful with this one. Soy can really drive your natural testosterone level down. It is know that raising estrogen levels will raise IGF-1 levels. Probably better off with just using a steriod that raises estrogen levels too.
 

Tom 185

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hah so according to him...the more igf-1 you have..the shorter u live
 
TeamSavage

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i was going to mention that it (soy) has been linked to increases in estrogen.. i can't source it right now, and i don't want to search... but i know i've read it before
Yes, this is definitely true. That's why so many women take it as a natural menopause treatment. A little here and there probably doesn't hurt, but I definitely wouldn't want to make soy a major source of protein.
 
Ziricote

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I hear you, I also read that casein and whey have a lesser effect on IGF-1 which might explain why some people seem to (or at least report to) have better gains with more whey.

IDK, if anything I found it interesting. I'd be interested to see how much on average these 30g+ amounts of milk/soy proteins effect estrogen levels. If it turned out that estrogen and test levels are not significantly altered it might be worth trying during a bulk.
 
TeamSavage

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IDK, if anything I found it interesting. I'd be interested to see how much on average these 30g+ amounts of milk/soy proteins effect estrogen levels. If it turned out that estrogen and test levels are not significantly altered it might be worth trying during a bulk.
I don't think soy actually increases estrogen levels. Rather, I believe the plant contains phytoestrogens that mimic estrogen's activity in the body. So if you supplemented heavily with soy, your estrogen levels as shown on bloodwork would likely remain unchanged, even if you were taking enough to increase estrogenic effects.
 
Ziricote

Ziricote

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I don't think soy actually increases estrogen levels. Rather, I believe the plant contains phytoestrogens that mimic estrogen's activity in the body. So if you supplemented heavily with soy, your estrogen levels as shown on bloodwork would likely remain unchanged, even if you were taking enough to increase estrogenic effects.
Ah, thanks for clearing that up.
 
Werewolf

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Your body sees the phytoestrogens from Soy as too high of estrogen and drives your natural testosterone output down.

Soy is consider the number one preventable cause of low testosterone in men.
 
Grunt76

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hah so according to him...the more igf-1 you have..the shorter u live
That sounds like pure BS because one of the main functions of IGF-1 is to make cells live longer. If all your cells live longer, you die quick? Somehow the logic seems failed to me.

Also his argument about mice being "older" can be very misleading. I mean if the treated mouse shows signs of becoming an adult quicker then the untreated one, then you could truthfully say IGF-1 makes you "appear older" but it doesn't mean what we think it means...
 
bpmartyr

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Are the phytoestrogens a concern with isolate? I had heard from Bobo that isolate was ok but to avoid whole soy and soy concentrates.
 

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