By Dayne Hudson

I've spoken before about why a carb is a carb, but interestingly it seems some sources of protein may be better than others.

A new study into 179 people over 60 undergoing resistance training 3 times a week for 12 weeks, has found dairy protein to be superior to soy protein for strength (1).

Now if you think because you're under 60 it doesn't apply to you - I'd say you're wrong! Getting into better protein habits now will prevent any poor choices later in life.

Furthermore, this is some good info to pass onto your grandparents and parents!

Also, as I've told you before, sarcopenia is a serious issue that effects the elderly; the loss of muscle mass as we age can spur on disabilities, lack of mobility and a poor quality of life!

That's why I recommend that the whole world should have a high protein diet and lift weights! 

This research gave the subjects at least 20 grams of protein per meal - more than 1.2g/kg of body weight - with the type given dependent on the group they were randomised in.

There were three protein options: soy, dairy and the usual protein intake of the subjects (which was less than 1.2g/kg BW/day).

This was according to standard Australian protein intake.

The strength results are evident in this graph below - hold onto your hats!

 

Amazing huh!?

The dairy intake was far better than the soy option, and even the usual protein group.

And all of this even though the training between subjects was exactly the same!

It goes to show, it doesn't matter if your training is on point, if your nutrition isn't line with the latest scientific guidelines, you can really be doing your self a large disservice! 

However, other findings were that lean mass, physical function and mental health scores as well as the decrease in fat mass was the same for all the training groups.
 
So why the difference?
 
Well previous research shows that soy protein doesn't deliver the same muscle protein synthesis results as dairy protein (2).
 
Let's hear from the researchers from the above citation:
 
"This effect may be due to differences in the fundamental amino acid composition of the protein (i.e., its amino acid score) and its rate of digestion. Milk proteins, specifically casein and whey, are the highest quality proteins and are quite different in terms of their rates of digestion and absorption. New data suggest that whey protein is better able to support MPS than is soy protein, a finding that may explain the greater ability of whey protein to support greater net muscle mass gains with resistance exercise."
 
So there we go; the amino acid score and quality of the proteins in dairy is superior to soy, but doesn't explain why the group having less protein gained more strength.
 
But the researchers for feature study on this article (1) do offer this: 
 
"It is more likely that the attenuation of the strength increase in the high protein soy group was due to some [direct] effect of the soy inhibiting the increase in strength"
 
They also suggest that soy performed worse because of the compounds in soy protein that are capable of exerting estrogen-like effects.
 
But the take home message is simple - stay away from soy, and get stuck into your dairy/whey protein - regardless of your age!

 

"Stay Fit, Stay Flexed!"

 

REFERENCES

(1) Thomson, Rebecca L., et al. "Muscle strength gains during resistance exercise training are attenuated with soy compared with dairy or usual protein intake in older adults: A randomized controlled trial." Clinical Nutrition (2015).

(2) Phillips, Stuart M., Jason E. Tang, and Daniel R. Moore. "The role of milk-and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons." Journal of the American College of Nutrition 28.4 (2009): 343-354.

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