Casein – hero or villain?

Highlights:

-Casein is a very good source of slowly released protein

-Casein isolated from whey (the other part of milk) has been associated with cancer and other diseases

-Whey protein is protecting the body against the negative effects of casein

-Casein is most effective if used together with whey protein

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Casein is the name describing a group of related proteins which account for some 80% of proteins found in cow milk. In the process of cheese production, casein is isolated from whey (which was once considered a useless by-product) and the resulting product (cheese, curds) is almost 100% casein.

Hero

Casein – both in form of cheese and as a powder – became notorious among bodybuilders for its slow release in the system. The bioavailability (BV – Biologic Value) of casein is not very high (77 comparing to up to 159 for whey isolate) but as it has a peculiar property of forming a clog in the stomach which can provide for proteins during about 5 hours (as opposed to 1,5 hours for whey protein drinks).

This way casein can be of great use in every situation where the protein intake is limited for a prolonged period of time. Most bodybuilders use casein (in fact eat some cheese) before the sleep to avoid any possible use of muscle protein for normal metabolic needs during the night.

This is not all. It seems that casein can possibly beat even the cherished darling of bodybuilders and coaches, the mighty whey protein.

A study by Demling/Desanti of Brigham and Women’s Hospital, Boston, Mass. (Effect of a Hypocaloric Diet, Increased Protein Intake and Resistance Training on Lean Mass Gains and Fat Mass Loss in Overweight Police Officers) compared 3 groups of overweight individuals: first group received no supplementation, second group had whey protein supplementation and the third group used casein.

The results were surprising: the casein group did significantly better that the whey group – in strength increases, fat loss and lean muscle mass increases.  In the words of study authors: “This significant difference in body composition and strength is likely due to improved nitrogen retention and overall anticatabolic effects caused by the peptide components of the casein hydrolysate.”

Villain

Casein consumption has been associated with cancer. The correlation is so evident and supported by so many studies that it just can’t be ignored.

In a best-selling book of 2004 The China Study professor T. Colin Campbell argued that some forms of animal protein – and especially casein – cause breast cancer as well as other forms of carcinomas. The same book shows relation between casein and auto-immune disorders (the mechanism being inhibition of Vitamin D activation in kidneys).

An important clinical study, also by T.C. Campbell resulted in all the rats in a group fed aflatoxin and 20% casein diet developing pre-carcinomas while none of the rats fed aflatoxin and 5% casein diet developed ones.

Many clinical studies linked cancer to animal proteins in general and advice the diet to be based on plants.

However, in the case of whey protein (the other 20% of milk), there is a growing evidence showing protective, anti-cancerous properties.

It can be safely stated that any health problems caused by milk have been always linked to casein and almost never to whey protein.

It is interesting to mention that in pre-industrialized China, cow milk was practically unknown and Chinese people didn’t know many of the diseases plaguing the West.

We often hear that the casein – cancer link is all based on T.C. Campbell’s work. This is not precise. Most studies simply didn’t use only casein but evaluated it together with other “villains”. Still, casein is at least suspicious of the crime of causing cancer together with other suspects like animal proteins and fats.

One example is the 1990 Canadian study concluding:  “Thus, a diet containing 20% of cooked sucrose, or 40% of casein and beef tallow cooked together, promotes the growth of colonic microadenomas in initiated mice and rats, and would appear to contain promoters for colon cancer” (Promotion of Colonic Microadenoma Growth in Mice and Rats Fed Cooked Sugar or Cooked Casein and Fat).

Author Ori Hofmekler writes that “Thermolyzed casein in particular has shown to cause the growth of aberrant crypt foci (ACF tumors) and colon cancer”, his statement being based on several clinical studies.

In a 1964 paper, authors H. Shay, M. Gruenstein and M.B. Shimkin conclude that “Diets containing large proportions (27–64%) of casein promoted the development of mammary adenocarcinomas in female rats of the Wistar strain receiving daily gastric instillations of 3-methylcholanthrene.”

C.N.S. McLachlan studied the long-term correlation between casein consumption and ischemic heart disease mortality. The author found strong correlation between casein consumption, ischemic heart disease and also between casein consumption and Type-I Diabetes.

In 1949, authors A. Tannenbaum and H. Silverstone speculated that higher protein intake could positively affect tumors. They happened to experiment with casein and in case of hepatomas they found positive correlation: the more casein in the diet, the more hepatomas in mice.

X.M. Zhang and colleagues (1992) found that thermolyzed casein is causing colon cancer in rats.

In 1985, M.G. Le, L.H. Moulton, C. Hill and A. Kramar studied 1,010 cases of breast carcinomas in France, compared to a control group of 1,950 individuals with non-malignant diseases. Their verdict: “the risk of breast cancer was found to be positively associated with frequency of cheese consumption”.

What should we make of this?

So what’s the bottom line here? Should we really stop eating this hugely popular and apparently useful protein? Well, this is really up to you. The scientific studies are not conclusive.

At least one study (the 1952 Engel/Copeland The Influence of Dietary Casein Level on Tumor Induction with 2-Acetylaminofluorene) concluded that rats fed with 9% casein diet had higher cancer prevalence than those fed with 60% casein diet. It must be noted that the authors themselves linked the lower cancer rate to lover caloric intake as the substitute to casein in the first group was sugar.

Our own conclusion is that eating large amounts of casein is risky and more research is needed to establish its safety.

Casein plus whey will do the trick

While there is a strong suspicion that isolated casein (and we don’t mean the powder only, every cheese product is essentially casein isolated from whey, the other milk component) can cause a number of serious health problems, there is a very significant evidence that whey protein can balance and negate those side-effects.

After all – there is a balance in the nature. Naturally occurring milk is casein + whey and this should be the most potent and safest combination. And it really seems to be so. In a study comparing three groups of athletes one was given whey and casein proteins, the second group used whey protein with BCAA (Branched Chain Amino Acids) and L-glutamine and the third group was given placebo.

The first group (casein+whey) did grow much more lean muscle mass than the second (whey+BCAA+glutamine) and third (placebo) group.

So what about drinking milk?

As we just mentioned, cow milk is a natural, perfectly balanced product comprising of the two most worthy (at least for bodybuilders) proteins: whey protein and casein.

The only problem with cow milk is that it’s been designed for calves, not humans.

Full 75% of us are suffering from lactose (main milk carbohydrate) intolerance and the problems with cow milk do not stop here (see the MILK article for more).

Whey proteins, for instance, are much more valuable if hydrolyzed (broken down to peptides) – your body will not waste the energy for digestion but it can use the amino acids directly.

Therefore, a combination of casein and whey protein isolates and hydrolytes with no lactose added is far superior choice to the ordinary cow milk (http://www.ncbi.nlm.nih.gov/pubmed/16937979 )