Probably one of the biggest differences between whey protein and soy protein is their source. Whey protein is an animal product, extracted from the watery substance that’s left over from cheese production. Therefore, it is unsuitable for anyone with allergies to dairy products or who is lactose intolerant. It also wouldn’t be suitable for vegans.

Soy protein, on the other hand, is a plant product, extracted from the soybean. This would make it suitable for vegans but not for people with soy allergies, which is a fairly common allergy.

So if you don’t have any dietary problems with either protein type, which one wins the whey vs. soy protein fight on a quality level?

There are a few different systems in place to measure protein quality. Digestibility is measured using a protein digestibility-corrected amino acid score (or PDCAAS). Officially, the highest score possible is 1.0. Both whey and soy proteins rate at 1.0, meaning they are both highly digestible. Unofficially though, whey protein has scored 1.14 so it’s probably just that little bit better.

Whey protein also seems to score just a little better in other quality tests. However, soy protein does have the advantage of helping to reduce cholesterol levels, thus reducing the risk of heart disease.

As far as amino acids go, these two types of protein are pretty much on a par; they both provide good quantities of all the essential amino acids.

In the end, the answer to the whey vs. soy protein question may just come down to personal preference. Both are very good, high-quality protein sources, with whey protein maybe coming in just slightly better than soy.

This entry was posted on Thursday, September 4th, 2008 at 10:33 am and is filed under Nutrition. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.