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

Milk is comprised of about 80% casein protein, and 20% whey. Normally, you couldn't visually differentiate the two: it just looks ... well ... liquid and "milky".

However, when you add an acid (i.e. vinegar) or enzyme (i.e. rennet; used in cheese production), the milk will curdle. This breaks apart the whey from the casein proteins.

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

In cheesemaking, the whey is siphoned off from the casein, and the solids are then drained through cheesecloth, further extracting any residual whey or water and leaving the firm casein solids, which are then shaped into blocks of cheese (the rest of the cheesemaking steps are omitted here-interesting but irrelevant).

Cottage Cheese: Whole Food Example of Casein and Whey

For a whole food, real world example, just think about cottage cheese (Little Miss Muffet was quite fond of her "curds and whey").

Cottage cheese is basically milk that has been separated into casein and whey via enzymes.  The curds (solids) are the casein and the liquid part is the whey. For this reason, 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.

One day scientists realized that the whey contained a very high level of fast digesting, bioavailable protein. There was a rush 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 is also poorly digested by the human body, which is a contributing factor to why dairy is so unfriendly to the human intestinal tract.

When Doesn't Whey Have Casein?

If you consume whole food sources of dairy,  you'll be consuming both whey and casein together.

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

A 100% casein protein powder, 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.

Milk protein isolate products may also contain some whey, as well as protein powder blends that intentionally contain both casein and whey protein. These are both exceptions to that standard.

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 whey isolates, there will be very little cross-over between the two.

Health reporter Mike Adams (July 31, 2010) points out that the upcoming flu vaccine has caused  oncern among US officials. The labels need to be changed because it appears to have caused a "higher than usual rate of seizures in children." The odd thing is that no one was told what the "usual" rate of seizures in children is. We've been told these shots are safe. If they can cause seizures, what else can they cause? Why haven't all these complications of vaccination been identified and reported?
 
"The labeling for one vaccine, CSL Limited's Afluria, has undergone changes this season to inform health care providers about an increased incidence of fever and febrile seizure.... The FDA said it was asking CSL to conduct a study of its vaccine in children."
 
Our comments: so the choice is between having a miserable kid for a few days or possible brain damage. We think kids can handle a few days of flu much easier than a lifetime of brain damage. And we know the MDs, pharmaceutical companies and the government run the other way when it comes to paying for this "side effect."

Is "vitaminwater" a healthy beverage? The Center for Science in the Public Interest has sued Coca-Cola, which makes the line of beverages, for falsely marketing them as healthy.

Coca-Cola's response? "No consumer could reasonably be misled into thinking vitaminwater was a healthy beverage."

That's funny, because I'm pretty sure the whole marketing strategy is to suggest that the beverages are healthy. CSPI notes that the brand name itself suggests that the beverage consists of nothing but vitamins and water, when it would be far more accurate to say that it consists of sugar and water, with about a penny's worth of vitamins added. And of course some artificial coloring.

And then there are the "flavors," which are identified with healthful words such as "defense," "essential," and "endurance."

Author John Robbins asks on Huffington Post, is it "okay for a corporation to lie about its products, as long as they can then turn around and claim that no one actually believes their lies?"

And, if so, how much of what surrounds us everyday are we expected to know is not what it appears to be?

This must be proof that there's a divine wisdom that loves us and wants us to be happy. Cocoa is known to contain flavanols, chemicals associated with improving the function of blood vessels, along with higher levels of antioxidants. Avoid brands that contain high fructose corn syrup (HFCS) and artificial flavorings. An eight-year study, of nearly 30,000 people aged 35 to 65, confirmed the results of previous, smaller studies into the health benefits of cocoa products ... even one square of chocolate can be beneficial. But researchers found that if the dose is increased by just six grams, there were 85 fewer heart attacks and strokes per 10,000 people.

For more information, go to http://healthfreedoms.org/a-chocolate-bar-a-day-can-cut-the-risk-of-heart-disease-and-stroke.

For a list of HFCS free chocolates (and other HFCS free foods as well), go to http://www.stophfcs.com/list.html.

Beware your breakfast cereal - HCFS seems to be in nearly everything these days - loads of soft drinks, processed foods, ketchup, salad dressing, cereal, cookies, yogurts, candies, bread - just go through your kitchen and you'll be amazed how many products contain this dangerous artificial chemical (always read labels when you shop.) Our advice - throw anything containing HFCS out.
In addition to being linked to obesity and containing dangerous levels of mercury (used in its production) a recent study reveals that HFCS causes scarring of the liver! Duke University Medical Center researchers state:
We found that increased consumption of high fructose corn syrup was associated with scarring in the liver, or fibrosis, among patients with non-alcoholic fatty liver disease (NAFLD).
We recommend you liberate yourself and your family from this bizarre chemical concoction. Why is this product used? Because it's cheap, not because it's good for you. (4) Read the rest of the article at: http://healthfreedoms.org/2010/03/22/high-fructose-corn-syrup-linked-to-liver-scarring/