Soy Versus Whey Protein - Soy Vs. Whey Protein - Which is Better?

Soy versus whey protein. The battle between soy protein and whey protein as a muscle building compound has been raging for a few years now.

Here at Middle Management, we lay out the facts so that you can make an informed decision on which protein source, soy protein or whey protein, fits your muscle building and fat burning needs.

Of course, if you are a vegetarian, soy is the best choice. For everyone else, the decision may prove more difficult.

We will examine the following criteria as we examine the soy vs. whey controversy:

• Biological Value (BV)
• Net Protein Utilization (NPU)
• Protein Efficiency Ratio (PER)
• Amino Acid Score (AAS)
• Protein Digestibility Corrected Amino Acid Score (PDCAAS)
• Protein Digestibility Percentage(PD%)
• Glutamine per 100 Grams
• Essential Amino Acids (EAA) per Gram
• Arginine per 100 Grams

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While both types of protein present general health benefits, we want the protein that gives us the largest dose of usable muscle building protein and essential amino acids. This will help increase a maintain lean muscle mass, which will also aid fat burning.

As you know, we are looking for hard facts and data to make decisions about our bodies. Therefore, without further delay, the facts about soy versus whey protein.

A Quick Note - Protein and Nitrogen

Amino acids are the building blocks of protein. Amino acids consist of four elements - carbon, hydrogen, nitrogen, and oxygen.

All three of the macro nutrients contain carbon, hydrogen and oxygen. Unlike carbohydrates and fats,however, protein also contains nitrogen.

This unique nature of proteins allows us to utilize the measures below to make decisions. Additional Facts About Protein

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Soy Versus Whey - Which has a Better Biological Value?

The Biological Value (BV) method uses nitrogen retention quantify protein quality. The Biological Value provides a measure of the amount of nitrogen retained from consumption of protein compared to the amount of nitrogen consumed when a person is in a "fasted" state (the stomach is completely empty).

The Biological Value indicates both how digestible the protein is and how available the protein is for use by the body. Biological value began as a percentage - A whole egg rated at 100% nitrogen absorbed.

As time progressed, protein powders became better sources of protein, exposing a flaw in the BV measurement system. Today, the number is on an adjusted scale such that a whole egg is has a BV of 100. This allows some processed proteins to have biological values greater than 100. Obviously, the higher the number, the better.

How do the BV values compare in the soy versus whey protein debate?

Round 1 - Soy vs. Whey Protein

Soy Vs. Whey Protein	BV
Soy Protein Concentrate	74
Whey Protein	104

Round 1 of the Soy Protein versus Whey Protein debate goes to...

Whey Protein.

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Soy Versus Whey - Which has a Better Net Protein Utilization?

Net Protein Utilization (NPU) is the amount of amino acids converted to protein inside the body versus the amount of amino acids from protein eaten.

The NPU measures the ratio of protein consumed through a person's diet, to the amount of nitrogen emission.

The value varies from 0 to 100 and is often interpreted as a percentage. A value of 100 means that the body uses 100% of the protein provided. Conversely, a value of 0 signifies that none of the nitrogen converts to protein in the body. Therefore, the higher the number, the better the protein.

How do the NPU values compare in the soy versus whey protein debate?

Round 2 - Soy vs. Whey Protein

Soy Vs. Whey Protein	NPU
Soy Protein Concentrate	61
Whey Protein	92

Round 2 of the Soy Protein versus Whey Protein debate goes to...

Whey Protein.

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Soy Versus Whey - Which has a Better Protein Efficiency Ratio?

The protein efficiency ratio measures the gain in body weight divide by the weight of the protein consumed for infant laboratory rats.

The FDA used the protein efficiency ratio to derive the recommended daily allowance of protein seen on food labels.

Some concerns with PER include the fact that rats utilize protein differently than humans, leading into some calculation errors. These errors cause a slight overestimation of animal protein and a slight underestimation of plant protein.

Also, PER measures only growth, and says nothing of maintenance. As a result, it might not be the best measure of the quality of protein for those of us attempting to burn fat.

How do the NPU values compare in the soy versus whey protein debate?

Any protein having greater than a 2.7 PER calculation is considered an excellent source of protein.

Round 3 - Soy vs. Whey Protein

Soy Vs. Whey Protein	PER
Soy Protein Concentrate	2.2
Whey Protein	3.2

Round 3 of the Soy Protein versus Whey Protein debate goes to...

Whey Protein.

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Soy Versus Whey - Which has a Better Amino Acid Score?

The amino acid score (AAS) is fast, consistent, and inexpensive. It measures essential amino acids in a protein compared to a reference protein. The AAS rates the protein on the most limiting amino acid found in the protein under consideration.

One limitation of the AAS is that it does not consider the digestibility of the protein.

A value greater than 1 indicates that the protein being considered contains a greater amount of essential amino acids than humans require.

How do the AAS values compare in the soy versus whey protein debate?

Round 4 - Soy vs. Whey Protein

Soy Vs. Whey Protein	AAS
Soy Protein Concentrate	0.99
Whey Protein	1.14

Round 4 of the Soy Protein versus Whey Protein debate goes to...

Whey Protein.

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Soy Versus Whey - Which has a Better Protein Digestibility Corrected Amino Acid Score?

The protein digestibility corrected amino acid score (PDCAAS) makes a correction for the limitation of the simple amino acid score described above.

Like the AAS, the PDCAAS measures the It measures essential amino acids in a protein compared to a reference protein. The reference protein meets the essential amino acid requirements of humans, and is given a PDCAAS of 1.0.

The Food and Agriculture Organization of the United Nations (FAO) set out to address the concerns about some of the measurements above with the PDCAAS measurement. As a result, many health experts recognize PDCAAS as the standard measure of protein quality.

This method is not without flaws, however. In particular, in 1990, the FAO/WHO decided that proteins having a PDCAAS higher than 1.0 would be rounded down to 1.0 to indicate that it meets or exceeds the requirements of the average human.

These essential amino acid needs of the average human may be significantly lower than the needs of bodybuilders, weight lifters, and other highly active individuals.

Because of the rounding down of proteins that have scores greater than 1.0, there is no way to discern differences between proteins with a PDCAAS score of 1.0 other than to refer back to the other measures that PDCAAS hoped to eliminate.

As indicated below, this lack of clarity is of particular concern in the soy versus whey protein debate.

How do the PDCAAS values compare in the soy versus whey protein debate?

Round 5 - Soy vs. Whey Protein

Soy Vs. Whey Protein	PDCAAS
Soy Protein Concentrate	1.00
Whey Protein	1.00

Round 5 of the Soy Protein versus Whey Protein debate goes to...

Push.

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Soy Versus Whey - Which has a Better Protein Digestibility Percentage?

The protein digestibility percentage (PD%) measures the percentage of protein eaten that is absorbed in the body.

Protein digestibility is the PD component of the PDCAAS above.

It is interesting to note that, while the FDA is replacing PER as the standard measure of protein quality with PDCAAS due to differences between humans and laboratory rats, the PD% is determined by evaluating laboratory rats.

How do the PD percentages compare in the soy versus whey protein debate?

Round 6 - Soy vs. Whey Protein

Soy Vs. Whey Protein	PD%
Soy Protein Concentrate	95%
Whey Protein	99%

Round 6 of the Soy Protein versus Whey Protein debate goes to...

Whey Protein.

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Soy Versus Whey - Which has More Glutamine?

Glutamine is a non-essential amino acid. Your body uses glutamine to transport nitrogen to your tissues.

Glutamine also increases muscle cell volume through cellular hydration. Glutamine supplementation also increases growth hormone levels, which leads to the muscle using fatty acids for fuel rather than blood sugar.

Those looking to build muscle should consume 3 to 5 grams of glutamine, 3 times per day.

It is obvious that we may prefer the protein that has the highest concentration of glutamine.

How do our contestants stack up in the soy versus whey protein battle?

Round 7 - Soy vs. Whey Protein

Soy Vs. Whey Protein	Glutamine per 100g of Protein
Soy Protein Concentrate	10.5g
Whey Protein	4.9g

Round 7 of the Soy Protein versus Whey Protein debate goes to...

Soy Protein.

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Soy Versus Whey - Which has the Most Essential Amino Acids?

Essential amino acids (EAA) are not produced in the body. You must obtain these essential amino acids through your diet.

You must have the right combination of non-essential and essential amino acids in sufficient quantities in order to build muscle. Therefore, a comparison of the essential amino acid profile is a necessary component in the soy versus whey protein comparison.

This comparison provides additional clarity on the amino acid scores (AAS and PDCAAS) listed above.

How do the essential amino acid profiles compare in the soy versus whey protein comparison?

Round 8 - Soy vs. Whey Protein

Soy Vs. Whey Protein	mg EAA per g of Protein
Amino Acid	Soy Protein	Whey Protein
Isoleucine (BCAA)	49mg	54mg
Leucine (BCAA)	82mg	89mg
Valine (BCAA)	48mg	82mg
Histidine	19mg	16mg
Lysine	64mg	88mg
Methionine	26mg	32mg
Phenylalanine	38mg	32mg
Threonine	38mg	65mg
Tryptophan	14mg	22mg
Totals	378mg	480mg

Round 8 of the Soy Protein versus Whey Protein debate goes to...

Whey Protein.

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Soy Versus Whey - Which has More Arginine?

Arginine is a non-essential amino acid that helps ward off both mental and physical fatigue.

Arginine also helps to facilitate muscle growth through promoting the release of both growth hormone and insulin in the body during intense exercise such as bodybuilding.

Arginine has become popular recently due to its ability to produce nitric oxide, which increases blood flow, and thus delivers more nutrients to the muscles and promoting growth.

An additional benefit of arginine is that it may lower LDL cholesterol levels in the bloodstream and increases lipid (fat) metabolism.

Who wins the soy versus whey protein battle in Round 9?

Round 9 - Soy vs. Whey Protein

Soy Vs. Whey Protein	Arginine per 100g of Protein
Soy Protein	7.6g
Whey Protein	2.9g

Round 9 of the Soy Protein versus Whey Protein debate goes to...

Soy Protein.

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Soy Versus Whey Protein - You Be The Judge

We examined several criteria in the soy versus whey protein debate. In general, the facts considered here are in favor of whey protein, especially if you choose to supplement your protein intake with a glutamine supplement and arginine supplement.

However, that is not to say that it is not a good idea to supplement with soy protein. Soy protein is shown to be an excellent source of protein and can be used effectively in bodybuilding supplementation, particularly for those who are vegetarians or lactose intolerant.

Soy Vs. Whey Protein	Protein Type
Criteria	Soy Protein	Whey Protein	Better Protein
Biological Value (BV)	74	104	Whey Protein
Net Protein Utilization (NPU)	61	92	Whey Protein
Protein Efficiency Ration (PER)	2.2	3.2	Whey Protein
Amino Acid Score (AAS)	0.99	1.14	Whey Protein
Protein Digestibility Corrected Amino Acid Score (PDCAAS)	1.00	1.00	Push
Protein Digestibility Percentage (PD%)	95%	99%	Whey Protein
Glutamine per 100g of Protein	10.5g	4.9g	Soy Protein
mg EAA per g of Protein	378mg	480mg	Whey Protein
Arginine per 100g of Protein	7.6g	2.9g	Soy Protein

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