PROTEIN DEBATE: Which Protein Is Best?


By: William Misner, Ph.D.

From 1996 until his retirement in 2006, Dr. Bill worked full-time as Director of Research & Development at Hammer Nutrition. Among his many accomplishments, both academically and athletically, he is an AAMA Board Certified Alternative Medicine Practitioner and the author of "What Should I Eat? A Food-Endowed Prescription For Well Being". - Dr Bill's Full Bio


A protein food strength or weakness is based on the quality and quantity of its essential amino acid profile for healthful growth effects. For example, soy protein generates known cardiovascular benefits, while whey protein reproduces significant muscle growth effects. Protein quality may therefore be judged by its essential amino acid yield per serving. The body cannot make essential amino acids for itself and is therefore dependent upon dietary sources.

ESSENTIAL AMINO ACIDS MILLIGRAMS PER 26 GRAMS
AMINO ACIDSOYWHEY
LEUCINE15462609
ISOLEUCINE BCAA9211333
VALINE BCAA940942
METHIONINE245443
ARGININE1428480
HISTIDINE489425
LYSINE11842222
PHENYLALANINE977831
TRYPTOPHAN595244
TOTALS903910491

Non-essential amino acids are also beneficial for replacing exercise-cannibalized amino acids from muscle mass. Therefore, the amino acid profile for soy and whey may also be compared in terms of their non-essential amino acids donor potency:

AMINO ACIDS MILLIGRAMS PER 26 GRAMS
AMINO ACIDSOYWHEY
CYSTEINE244869
ASPARTIC ACID21802039
ALANINE808230
GLUTAMIC ACID35892683
GLYCINE78978
PROLINE940179
SERINE977180
TYROSINE714172
TOTALS102416430

These values represent individual amino acid content in soy and whey.

Next, compare soy and whey to other protein sources: human milk, eggs, and cow milk, beef:

COMPARISON OF AMINO ACID PROFILES IN COMMON PROTEINS [2] AMINO ACID (mg AA/g protein)
Amino AcidHuman MilkCow MilkEggBeefSoyWhey
Histidine262722341916
Isoleucine BCAA464754484954
Leucine BCAA939586838289
Valine BCAA556466504882
Lysine667870896488
Methionine423357402632
Tyrosine7210293809265
Threonine44447463865
Tryptophan171417121422
TOTALS421504512482432513

Blue notes highest amino acid value. Red notes lowest amino acid value. PROTEIN DIGESTIBILITY CORRECTED AMINO ACID SCORE (PDCAAS)Protein growth potency is judged by its weakest essential amino acid. The PDCAAS classifies protein quality for humans based on the amino acid requirements the most demanding age group (2-to-5-years) and is adjusted for digestibility. Only three proteins are considered "Complete" based on their PDCAAS score:

PROTEINPDCAAS
WHEY1.0
SOY1.0
EGG1.0
Grains & Legumes1.0
Grains & Vegetables1.0
Grains, Nuts, & Seeds1.0
Rice & Peas1.0
Legumes, Nuts, & Seeds1.0
Beef0.92
Rice + Milk0.92
Peas0.73
Oats0.57
Peanuts0.52
Rice0.47
Corn0.42
Wheat Gluten0.25

PROTEIN EFFECTS SERUM CHOLESTEROL LEVELS When rabbits were fed various foods then were examined for blood serum cholesterol after 28 days on each protein, the following results in serum cholesterol were reported:

PROTEIN SOURCEPOSTPRANDIAL SERUM CHOLESTEROL (mmol/l)
Soy Protein Isolates0.4
Soy Protein Concentrates0.6
Peanut Protein2.1
Wheat Gluten2.1
EGG White (raw)2.7
Pork Protein Concentrate2.8
Beef Protein Concentrate4.1
Casein (MILK)5.2
Skim MILK5.9
Whole EGG6.1

AMINO ACIDS ACCESS THE BRAIN, ENERGY LEVELS, MOOD, EMOTION, APPETITE, AND MUSCLE GROWTH HORMONE RELEASE

There are 4 main classes of amino acids. When amino acids from the same class are present simultaneously with others, they compete for entry through the blood-brain barrier. A single free-form amino acid will cross blood-brain barrier with greater potency effect. When, for example, Glutamine, Arginine, Tryptophan, Glycine, and the BCAA's (Leucine, Valine, and Isoleucine) are taken as free form amino acids without having to compete against other amino acids in their class, they have been reported to stimulate maximal hGH release with muscle growth rate increased effects. Each of the 4 classes are listed with their corresponding amino acids:

LARGE NEUTRAL CLASS: Tryptophan Phenylalanine Tyrosine Methionine LeucineBCAA ValineBCAA IsoleucineBCAA

SMALL NEUTRAL CLASS: Asparagine Glutamine Proline Serine

ACIDIC CLASS: Glutamic Aspartic

BASIC CLASS: Arginine Ornithine Lysine

The protein food's amino acid profile affects its biological value. Protein food sources can be consumed together regenerating a complete protein rating PDCAAS 1.0-score. One protein may have a better effect if it is mixed with another based on the strength and weaknesses of its amino acid profile. Only 3 protein amino acid profiles have been rated as "Complete" or with a perfect PDCAAS score of 1.0. "Complete Proteins" are SOY, WHEY, & EGG WHITES. PDCAAS means "Protein Digestibility Corrected Amino Acid Score." An argument can be made for consuming whey protein during strength or speed training cycles, and soy during endurance cardio training cycles keeping the carbohydrates to protein ratio of 3-4 to 1 as total dietary protein of 1.7 grams during speed/strength training, but no more than 1.4 grams/kilogram bodyweight during endurance training cycles. Only small portions of protein should be consumed during exercise, which operate to blunt protein deficits created by exercise. During the first 30 minutes after exercise it is important that the athlete consume a large protein meal of 40 grams with 120-160 grams carbohydrates to refill the lean muscle mass stores for recovery and muscle growth after exercise. Too much dietary protein above 1.7 grams per kilogram body weight is not necessary. It increases the risk of elevating nitrogen, ammonia, urea, dehydration, and increased feelings of malaise from nitrogen toxicity, impacting stress on the liver and kidneys. More is not always better, but balance is always key. [3]

[1] Director Research and Product Development EMG, Whitefish, Montana 1-800-336-1977.

[2] National Research Council. Recommended Dietary Allowances, 10th ed. National Academy Press, 1989; Values for whey hydrosylate are from Boza, JJ et. al. (12) and may vary slightly depending on how the whey is produced; Values for soy isolate (Supro-620) are from Young VR. (13).

[3] Misner, W.D., The Great Hammer Protein Debate: Which Protein Is The Best, How Much And When? THE JOURNAL OF ENDURANCE:2001:#8.