Does Whey Have Casein? | Ask The Fitness Nerd

[ 10 ] February 10, 2009 |

Does Whey Protein Also Contain Casein? We Sort Out The Milk Protein Mystery Once and For All.

Dear Fitness Nerd,Picture of Milk, Yogurt and Cottage Cheese on Table

I’m a little confused about whey and casein protein. Does whey also contain casein? And vice versa?  All I know is that both whey and casein are in milk.  Can you help me sort this out? — Janine (Dunwoody, GA)

You’re right that both whey and casein are proteins in milk.

But the important thing to grasp is that they are two totally different kinds of protein.

So in their purest form – isolated from the milk itself (for example in protein powder supplements) — whey typically doesn’t contain meaningful amounts of casein. Same goes for casein in regards to whey content.

Understanding Milk Proteins: Whey vs. Casein

The easist way to think about this is in the context of milk.

Milk contains about 80 percent casein protein, and 20 percent whey. Under normal conditions, you would never be able to differentiate between the whey and casein in milk visually. It just looks … well … liquid and “milky.”

However, when you add an acid or enzyme like rennet (which is used in cheese production), the milk will curdle. This literally separates the whey from the casein proteins.

The result is that the whey — which is a semi-clear liquid — will rise to the top, while the casein (which is heavier and coagulates in the presence of an acid or enzyme) will usually sink to the bottom.

In cheesemaking, the whey is siphoned off from the casein, and the solids are then drained through a cheese cloth, further extracting any residual whey or water and leaving the firm casein solids, which are then shaped into blocks of cheese (there are more steps, but I won’t get into them here.) 

Cottage Cheese: Whole Food Example of Casein and Whey

For a whole food, real world example, just think about cottage cheese (also known as “curds and whey,” for good reason.)

Cottage cheese is basically milk that has been separated into casein and whey via enzymes.  The lumpy curds are the casein and the liquid part is the whey. So in this regard, when you eat cottage cheese you are getting both whey and casein protein.

Here’s the kicker: Outside of cottage cheese, for years whey was typically discarded or fed to livestock.

This practice persisted until scientists realized that the whey contained a very high level of fast digesting, bioavailable protein. Suddenly people started rushing to figure out ways to turn the liquid into a powder and the entire whey protein craze took off.

Difference in Whey Versus Casein

Whey and casein have very different chemical properties.

While whey digests quickly, casein can take hours to be broken down and absorbed. Casein is poorly dissolved in water and cannot be denatured (meaning it won’t change it’s natural structure with the application of heat or chemicals.)

This makes whey an ideal protein right after you workout, when you want to make sure plenty of protein is available to assist with recovery.

Casein, on the other hand, releases amino acids more slowly into your body, almost like a protein IV. This can help blunt muscle breakdown for hours after weight training.  A combination of the two appears to be ideal, based on recent research.

Casein is also an ideal protein to consume in the evening or before you go to bed,  since it may help reduce muscle breakdown during sleep. A serving of low-fat cottage cheese, skim milk, yogurt, Quark or kefir before bed is a low-fat, high-protein source of both casein protein and whey, although as I pointed out earlier, these products tend to have more casein than whey by volume.

When Doesn’t Whey Have Casein?

If you consume whole food sources of dairy,  you’ll be consuming both whey and casein together. There is zero wrong with this.

However, if you take a 100% whey protein powder, there will be little to no casein present in the protein. 

Same goes for a 100% casein protein powder, which will have isolated any residual whey out of the casein. The reason for this is that the filtration and isolation process more or less removes all traces of fat and the other protein. Casein molecules are “larger” and hence won’t make it through most whey filtration processes.

The exceptions in terms of protein supplements are things like milk protein isolate products, which may also contain some whey, as well as protein powder blends that intentionally contain both casein and whey protein.

Also protein powders that are labeled  ”Whey Protein Concentrate” may also have trace amounts of casein, since the filtration process used to make concentrate products doesn’t capture all of the casein.

However, if you are consuming either whey isolates or casein isolates, there will be very little cross-over between the two.

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Category: Ask The Fitness Nerd, Diet and Nutrition, Protein

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Comments (10)

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  1. Terry (1 comments) says:

    I am taking whey protein and concerned about the cholesterol level in it. I am borderline high cholesterol, hence working out 3 times a week with weights and cardio. Am I doing damage in the long run with the whey powder?

  2. Diane (1 comments) says:

    The book The China Study states that “casein which makes up 87% of cow’s milk protein promoted all stages of the cancer process.” (p. 6)  Can a person be assured that whey will not promote the cancer process?

  3. Jeanette (1 comments) says:

    What about the levels of lactose in the various products? I’d think the powders wouldn’t have any because it’s filtered out but I’m not sure. Every dairy based protein powder I tried made me sick (I’m lactose intolerant).

  4. Je (1 comments) says:

    Does the casein protein in milk prevent they whey protein from being absorbed quickly? I read that the casein coats the digestive linings preventing other things from disgesting…is this true?

  5. Adam (1 comments) says:

    Jeanette, if you are lactose intolerant then you probably want to stay away from Casein.

  6. Gemma (2 comments) says:

    A much better option for protein powders is a fermented rice protein or a pea protein, neither of which promote any of the detrimental effects of casein and whey. Casein has been intrinsically linked with massively speeding up tumour growth, why would anyone want to drink this daily? Sun Warrior rice protein has a 98% digestion and absorption into the body, and due to the high levels of IP6 is a massive cancer preventative.
    Whey and casein powders are certainly doing damage in the long run.

    • Matt (194 comments) says:

      Thanks for stopping by Gemma. Can you please provide some citations on the connection between casein and whey and their being “intrinsically linked with massively speeding up tumor growth?” I will do my own research, as well.

      • Domagoj (1 comments) says:

        China Study’s claim has been negated in a sense that ANY complete protein will speed up tumor growth in rats that are “poisoned” with aflatoxin. Veggie-type proteins used in those experiments were not complete protein and did not show that effect.

        • Tim Dearman (2 comments) says:

          In a word, that is utter BS.
          Not only is casein a carcinogenic trigger used literally to induce cancer in test animals, but their is much more CURRENT published research regarding the nature of animal versus plant protein – in particular regarding the presence of carnitine & choline in animal (egg, meat & dairy) protein which when ingested endogenically – IOW, eaten, the gut bacteria break it down into TMAOs which are both powerful carcinogens and inflammatory agents contributing to cadiovascular disease.
          You need MUCH better sources of information!


          N. D. Ferrari III, L. S. Nield. Smelling like dead fish: A case of trimethylaminuria in an adolescent. Clin Pediatr (Phila) 2006 45(9):864 – 866

          H U Rehman. Fish odour syndrome. Postgrad Med J 1999;75:451­452 1999 75(NA):451­ – 452

          Z. Wang, E. Klipfell, B. J. Bennett, R. Koeth, B. S. Levison, B. Dugar, A. E. Feldstein, E. B. Britt, X. Fu, Y.-M. Chung, Y. Wu, P. Schauer, J. D. Smith, H. Allayee, W. H. W. Tang, J. A. DiDonato, A. J. Lusis, S. L. Hazen. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature 2011 472(7341):57 – 63

          K. Rak, D. J. Rader. Cardiovascular disease: The diet-microbe morbid union. Nature 2011 472(7341):40 – 41

          M. G. Busby, L. Fischer, K.A. da Costa, D. Thompson, M.H. Mar, S. H. Zeisel. Choline- and betaine-defined diets for use in clinical research and for the management of trimethylaminuria. J Am Diet Assoc 2004 104(12):1836 – 1845

          J. E. Lee, E. Giovannucci, C. S. Fuchs, W. C. Willett, S. H. Zeisel, E. Cho. Choline and betaine intake and the risk of colorectal cancer in men. Cancer Epidemiol. Biomarkers Prev. 2010 19(3):884 – 887

          NA. Choline: There’s something fishy about this vitamin. Harv Health Lett 2004 30(1):3

          E. Ackerstaff, B. R. Pflug, J. B. Nelson, Z. M. Bhujwalla. Detection of increased choline compounds with proton nuclear magnetic resonance spectroscopy subsequent to malignant transformation of human prostatic epithelial cells. Cancer Res. 2001 61(9):3599 – 3603

          Subcommittee on the Tenth Edition of the Recommended Dietary Allowances, Food and Nutrition Board, Commission on Life Sciences, National Research Council. 1989. Tenth Edition of the Recommended Dietary Allowances.

          Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT, Britt EB, Fu X, Wu Y, Li L, Smith JD, Didonato JA, Chen J, Li H, Wu GD, Lewis JD, Warrier M, Brown JM, Krauss RM, Tang WH, Bushman FD, Lusis AJ, Hazen SL. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013 Apr 7.

          Zeisel SH, Mar MH, Howe JC, Holden JM. Concentrations of choline-containing compounds and betaine in common foods. J Nutr. 2003 May;133(5):1302-7.

          J. Demarquoy, B, Georges, C. Rigault, M.C. Royer, A. Clairet, M. Soty, S. Lekounoungou, F.L. Borgne. Radioisotopic determination of l-carnitine content in foods commonly eaten in Western countries. Food Chemistry, Volume 86, Issue 1, June 2004, Pages 137–142

          W.H. Wilson Tang, M.D., Zeneng Wang, Ph.D., Bruce S. Levison, Ph.D., Robert A. Koeth, B.S., Earl B. Britt, M.D., Xiaoming Fu, M.S., Yuping Wu, Ph.D., and Stanley L. Hazen, M.D., Ph.D. Intestinal Microbial Metabolism of Phosphatidylcholine and Cardiovascular Risk. New England Journal of Medicine 368:1575-1584.

          E. L. Richman, S. A. Kenfield, M. J. Stampfer, E. L. Giovannucci, J. M. Chan. Egg, red meat, and poultry intake and risk of lethal prostate cancer in the prostate-specific antigen-era: Incidence and survival. Cancer Prev Res (Phila) 2011 4(12):2110 – 2121

          E. L. Richman, M. J. Stampfer, A. Paciorek, J. M. Broering, P. R. Carroll, J. M. Chan. Intakes of meat, fish, poultry, and eggs and risk of prostate cancer progression. Am. J. Clin. Nutr. 2010 91(3):712 – 721

          M. Johansson, B. Van Guelpen, S. E. Vollset, J. Hultdin, A. Bergh, T. Key, O. Midttun, G. Hallmans, P. M. Ueland, P. Stattin. One-carbon metabolism and prostate cancer risk: Prospective investigation of seven circulating B vitamins and metabolites. Cancer Epidemiol. Biomarkers Prev. 2009 18(5):1538 – 1543

          C. Nanni, E. Zamagni, M. Cavo, D. Rubello, P. Tacchetti, C. Pettinato, M. Farsad, P. Castellucci, V. Ambrosini, G. C. Montini, A. Al-Nahhas, R. Franchi, S. Fanti. 11C-choline vs. 18F-FDG PET/CT in assessing bone involvement in patients with multiple myeloma. World J Surg Oncol 2007 5(NA):68

          E. L. Richman, S. A. Kenfield, M. J. Stampfer, E. L. Giovannucci, S. H. Zeisel, W. C. Willett, J. M. Chan. Choline intake and risk of lethal prostate cancer: Incidence and survival. Am. J. Clin. Nutr. 2012 96(4):855 – 863

          E. Ackerstaff, B. R. Pflug, J. B. Nelson, Z. M. Bhujwalla. Detection of increased choline compounds with proton nuclear magnetic resonance spectroscopy subsequent to malignant transformation of human prostatic epithelial cells. Cancer Res. 2001 61(9):3599 – 3603

          And for a synopsis of the studies, see “Carnitine, Choline, Cancer and Cholesterol: The TMAO Connection” at where they synopsize real vetted published research rather than dealing in faddist belief.

          Of course, the actual

  7. Pam (1 comments) says:

    The problem with rice protein is it contains brown rice and recent reports indicate high levels of arsenic.
    I am looking to good vegetarian protein sources and whey causes a lot of mucus (as does milk). No idea why. I am lactose intolerant but whey is not supposed to have much lactose anyway.

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