(31-03-11) Whey Vs. Soy: What?s the Real Story?

Health professionals have been debating the relative merits of different
protein supplements for as long as I?ve been in the field.

Should you use soy protein? Whey protein? Casein? Is there a difference?

The pro-soy contingent likes to point to studies showing a modest decrease in
cholesterol and potential benefits on cancer, menopausal symptoms and bone
density, but much of this is heavily disputed. The American Heart Association
no longer recommends soy for heart disease and the FDA is currently reviewing
its policy on soy health. And there have been more than a few well-credentialed
experts who have been extremely vocal on the dangers of soy, pointing to the
phytates (which bind to minerals making them less available), the goitrogens
(which may suppress thyroid function) and the mildly estrogenic effects of soy
which could be a problem for many people.

?At this time it is difficult to know for sure what the actual benefits of soy
product or soy supplement consumption would be. There is a great deal of
controversy regarding the benefits and dangers of soy ingestion?, says Ray
Sahelian, MD, whose moderate position is a model of balance and fairness.

On the other hand there?s very little controversy about whey. Nearly all the
studies using whey protein have been positive, noting benefits on appetite,
weight control, blood pressure and even IBD (colitis).

But no study has ever done a head-to-head comparison of whey vs soy
specifically looking at metabolism, fat loss and satiety (a feeling of
fullness).

But a study just published in the American Journal of Clinical Nutrition does
exactly that.

Researchers started with the premise that dietary protein stimulates
metabolism and fullness more than either carbohydrate or fat, but pointed out
that little is known about the differences between different protein sources.
So they took 23 lean healthy subjects and put them on a supplement of either
whey protein, casein protein or soy protein. (Casein and whey are the two major
proteins found in milk and dairy products.)

Then they measured the ?thermic effect? (which is how much heat- calorie
burning- is produced in the body after eating).

The three groups each ate a meal of 50% protein from either whey, soy or
casein, plus 40% carbohydrate and 10% fat. A fourth group- control- was fed a
very high carb meal (95% carbs).

All three protein meals produced greater thermic (calorie-burning) effects
than the carb meal; but the whey protein was the clear winner, beating out both
the soy protein and the casein. Cumulative fat burning was also significantly
greater after the whey-protein meal.

Interestingly, subjective appetite reports suggested that casein and soy were
more satiating than the whey, but the subjects ?liked? the whey much better!
This finding should be interpreted carefully, since many other studies have
shown that at typical levels of consumption whey is more satisfying than other
protein powders.

Source: jonnybowden.com

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