I was always told not to use............
Help me understand this Guru's
Best overall break down of Proteins I could find: Whey vs Soy vs Casein vs Egg white
http://www.muscleandfitness.com/nutrition/gain-mass/protein-face
Note comment about the estrogen receptors and daidzein. Also, Glutimine and Arginin.
http://www.timinvermont.com/fitness/soyvswhy.htm
Source: Elite Fitness: Online Bodybuilding Magazine
6. Soy Protein Isolate benefits for Bodybuilders
Animal research suggests some great advantages of using soy protein isolate as a bodybuilding supplement. Research has shown that the isoflavone daidzein found in soy-protein isolate might have a gender specific normalizing effect on sex-hormone production. Lab animals experienced testosterone and growth hormone excretion as well as muscle growth in males, while the female animals experienced a decrease in these hormones and fat loss.
Daidzein is a key isoflavone found in soy that acts as a potent phyto-estrogen. It is structurally a very weak "pseudo-estrogen" (about 1000 times weaker than the body's primary estrogen estradiol). This is good news to the bodybuilder because weak estrogens like daidzein will compete with stronger estrogens like estradiol for available receptor sites to "bind" to. By binding to the receptor sites daidzein then "blocks" the stronger estrogens from binding to and activating receptor sites. With the daidzein isolflavone attached, estrogen receptor sites remain inactive. This inactivity further minimizes the negative effects of estrogen in the body. Many researchers believe this effect is the reason soy protein is linked to a reduction in the risk for many forms of breast, endometrial, and prostate cancer. This mechanism works similarly to the prescription drug Nolvadex (tamoxifen citrate)--an anti-estrogen staple in the bodybuilding community.
Research also indicates that the soy-protein isolates may reduce nitrogen loss and keep you in a positive nitrogen balance to better facilitate muscle growth. The human body can only repair and build muscles when it has a positive nitrogen balance.
Of particular interest to the bodybuilder is Soy Isolates high concentration of the amino acids glutamine and arginine. These two aminos are extremely important to a body builder for their ability to release growth hormone, aid in immune system functions, and for their ability to speed muscle cell recovery.
Glutamine (per 100g)
Soy 10.5g
Milk Protein 8.8g
Whey 4.9g
Many bodybuilders understand the importance of the essential amino acid L- glutamine to their muscle building supplementation. What many bodybuilders don't know is that soy protein isolate has the highest concentration of glutamine among protein sources-over twice that of whey protein! (7) Glutamine has been used for years in hospitals to speed muscle cell recovery and improve maintenance of muscle mass during periods of starvation, infection, and exercise trauma. (8) Glutamine supplementation has been shown to promote muscle glycogen accumulation, which has been linked to an increase in muscle protein synthesis. (10) Glutamine has also shown the ability to increase muscle cell volume through the process of cellular hydration. (11) Glutamine supplementation in as little as 2 grams per day has been shown to increase plasma growth hormone levels. This increase in growth hormone has been shown to help shift the fuel for muscle from glucose to fatty acids. (9) Research has suggested that a bodybuilder should consume between 8 - 15 grams of glutamine each day. Supplementing 3-5 grams of glutamine 3 times per day has been shown to elicit a positive response without stimulating the excretion of glutamine in the urine.
Arginine (per 100g)
Soy 7.6g
Beef 6.3g
Egg 5.8g
Cassein 3.7g
Whey 2.9g
L-Arginine is another important amino acid with respects to body building. Arginine plays several roles in the body such as fighting mental and physical fatigue, but its main job is to assist with growth. This amino acid promotes the release of two highly anabolic hormones, insulin and growth hormone. Arginine promotes gains further by assisting in recovery from post workout muscle trauma through its ability to speed tissue healing. This amino acid aids in the detoxification of the liver by removing ammonium from the body. Arginine has also shown the ability to lower LDL cholesterol and triglyceride levels in the blood. Arginine is used in the medical treatment of angina, congestive heart failure, male infertility and wound healing. Soy isolate protein contains higher amounts of this important amino acid than any other protein source.
As a hard training bodybuilder, your body needs protein every 2 -2 1/2 hours even if you may not think you need it. The human body does not store protein long term as it does for fat and carbohydrates. Instead, your body holds amino acids in three pools that provide the body's necessary protein for fuel. These pools are constantly in a state of flux and are replenished either from dietary protein or the breakdown of muscle. It is extremely important to keep these amino acid pools topped off through the feeding of protein every 2 - 2 1/2 hours. When feeding stops, there is a fall in protein synthesis and a rise in protein breakdown. This translates into a loss of lean body mass after extended periods without protein.
Other Sources:
http://www.bodybuilding.com/fun/can-adding-soy-protein-lead-to-more-growth.html
http://www.bodybuilding.com/fun/drobson71.htm
Don't ask me any questions as I don't know anymore than what I have just read
Semper Fi
