Will I get the same benefits from the soy protein powder as the whey product?

Provided you are eating a balanced diet including other protein sources, yes you will experience the same overall benefits.  One to one though, Whey does have some benefits that other protein sources don't, but similarly soy has benefits that whey doesn't.

Protein, as most of us know is made up of amino acids.  Each protein food will have a different composition of amino acids.  Complete proteins have all the amino acids and incomplete proteins have some.  There are 9 essential amino acids, required through diet and 13 non-essential amino acids that the body can produce.  A daily diet that contains all amino acids is considered balanced in protein, regardless of just one meal or food being incomplete.

To create a complete protein things like rice & beans can be combined...not a meat, whey or soy in sight!

Whey Protein contains all the essential and branched chain amino acids, and can be either powder, concentrate or isolate.  Isolate has the highest percentage of protein and lowest percentage of lactose and milk fat.  Many whey proteins are fortified with the missing amino acids.

Soy protein is a complete protein (essential and non-essential) also with high level of BCAA's.  Similarly there is concentrate and isolate, isolate having the highest percentage of protein.

Whey is higher in BCAA's (Leucine is the one BCAA that is almost the same in both soy and whey). 

However soy is higher in glutamine and arginine, which are 2 important amino acids involved in muscle growth and nutrient transport.

Soy contains phytoestrogens that exhibit estrogen like effects in the body, to women this can either be a good thing for hormones and weight maintenance or not so good - soy seems to affect each person differently.  Refer to this earlier post for more information on the soy debate


In the last question we touched on the Biological Value of a protein.  The BV is a measure of the efficiency of protein utilization by the body.  Whey protein has a BV of 104 and Soy protein has a BV of 74.  Egg=100, uncooked beef=80.  Although it has a lower BV, your soy protein is supplemental to your diet (ideally), so other proteins will fill in the gaps.  Don't forget you also get proteins from most foods, including the training staples - rice, oats & broccoli.

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) assesses the digestibility of a protein, both whey and soy protein have a PDCAAS score of 1.00.

In a nutshell, Whey does come out better on most criteria.  But this does not mean you should throw out your soy protein for the sake of an upset stomach. What is important to you specifically, is that your digestive system told you that it didn't like whey.  Poor digestion can disrupt nutrient absorption and energy levels - so the benefits you will now receive from a happy tummy will completely outweigh any amino acid score or whey protein marketing guff.

Many of us tend to get hung up about this whole protein shake thing.  What we need to realize is that we are not going to waste away a kg of muscle just because we don't do the "post-workout shake" or the "pre-bed protein hit" or the "omg I have to have protein the second my alarm goes off or any movement I make will lose muscle".  Your body just doesn't do that.  True muscle catabolism occurs through inactivity and actual malnutrition (malnutrition is not just skipping a post workout shake).  Slow muscle growth can be a genetic thing, or can be a result of lazy training, type of training, little to no protein, stress, illness or poor sleep and recovery. 

So let's not hang all our coats on the protein rack when it comes to muscle growth, there are other factors to be considered.

To be big and strong, we need good protein sources and effective training.  The more variety we have in our diets with the less digestive upsets the stronger we will be.

19 August 10

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