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It’s an interesting thought to speculate, “Adult cows don’t drink milk. Should then, adult humans, be drinking milk?

When the calf reaches a certain age it’s stomach will stop making ‘rennet’, which is rich in the protease enzyme that can break down the milk proteins, specifically the long complex chain casein protein, for complete nutrition. At one month of age, the calf will be taken off its mothers breast milk. This is called weaning. It’s at this age that the calf stops making rennet and can no longer benefit from drinking it’s mothers milk. It must move on to eating grass.

For human babies, at the “weaning” stage they begin eating a wider variety of foods and less breast milk. The process of weaning happens naturally between 1 and 2 years of age because the baby’s stomach stops making the rennet to digest the casein. All dairy products, including milk, cheese, butter, yogurt, cream, ice cream, sour cream, whey, etc., become a danger to the human body and can not be digested after the age of 2. Even skim milk (5% of calories from fat) comes loaded with cholesterol and a variety of toxins. While a human adult can still digest most of the proteins in cows milk, we can not completely digest all of them and this is where the issue lies. Without the aid of rennet to digest the casein it becomes indigestible and even poisonous.

There has been much debate whether milk from another species is a healthful practice for humans to consume. With the short lesson in physiology, we can see that nature did not design any mammals to continue to consume the breast milk of it’s mother, or any other animal mother, after it has reached a certain growth point that nature has efficiently designed. Not to mention how milk changes when it’s pasteurized. The research on this is clear. A calf will die, within a few weeks, if fed it’s own mothers milk that has been pasteurized.

As we will see, there are specific parts to the milk proteins that are harmful because the amounts of each protein components vary from species to species. Cows, for example, have a greater percentage of their milk proteins as casein. Conversely, humans have a markedly lower amount of total casein in their breast milk. It is a vital understanding we must have when we decide what to put in our bodies. When we take from other species we must understand how their nutritional needs are vastly different from ours. As a protein consumer we need to know what proteins are the best to put into our human bodies and what processing was done to it before it goes into our mouths. How did the processing affect the protein as well as other nutrient contents. Am I getting what I think I’m getting? We need to know what we are putting into our bodies!

NOTE: The nutrition labels on packaged foods are based on the raw ingredients before any processing or heating has taken place. Once you have cooked the food to eat it the information on the label is inaccurate. You are getting less nutrients than you think. Heat destroys the biochemical makeup, thus the nutritional value, of your food.

Recent studies have brought to light that casein may be the protein that is the most harmful if consumed after weaning due to its toxic effects. Casein is a highly complex protein requiring specific enzymes, that adults don’t have, to break it down. Before we go any further I want to define what casein is.

From Wikipedia: “Casein (/ˈkeɪs.ɪn/ or /ˈkeɪˌsiːn/, from Latin caseus, “cheese”) is the name for a family of related phosphoproteins (αS1, αS2, β, κ). These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 20% and 45% of the proteins in human milk.[1] Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive, to a binder for safety matches.[2] As a food source, casein supplies amino acids, carbohydrates, and the two inorganic elements calcium and phosphorus.[3]”

“Calamitous calcium: Calcium from an animal source is the requirement of the Dairy Industry; without it and its effective absorption to support bone health, it has little reason for being. In the US we consume about twice the daily intake recommended by the World Health Organization. If this were benign, we could dismiss it as inconsequential. But it isn’t. Studies testify to its destructive qualities when the source is animal based; increased calcium in the blood may cause anything from joint and muscle pain to irregular heartbeat and coma; consumption of animal based dairy products, particularly at a younger age, is associated with an increased risk of hip fracture and breast cancer later, and on and on.”

The percentage of casein in human milk compared to all 5500 mammalian species on the planet is significantly the lowest. Humans do not need as much protein as other animals in order to develop due to longer development times. For example, a cow has about 15% protein (80% of the protein is casein), a rat has 45% protein, while a human as merely 3-5% protein (only 20% casein in early lactation and 40% casein in late lactation). The chart below shows the correlation between amount of protein and growth rates for various animals.

Comparison of milks from different species

Why All Milk is Not Created Equal

Not only are there many types of protein that makes up the protein portion of milk but there are multiple types of each of the proteins. For example, of the 6 major types of milk proteins, 4 of them are casein and the other 2 are whey. We will focus on casein for this article because of it’s significance in affecting human health.

Of the 4 types of casein, cows have a higher percentage of the alpha-casein (about 50%), Humans have a higher percentage of beta-casein (about 65%), and mares have an equal amount of alpha and beta-caseins (about 45% each). The components of milk protein is an important indicator of it’s purpose for the animal consuming it. This is an important point when we consider what it is we want to put into our human bodies for nourishment.

For example, if a rat were fed human breast milk it would not thrive. It may survive but it will not develop according to its genetic capability because it is being fed deficient food. As you can see from the comparison chart above, rats need 49% protein in their milk food for proper growth in the genetic time frame. All casein from other animals were designed for those animals to help them with the growth needed according to their species. While humans have casein, it’s a form designed to be digested by humans and even then, for only a short time in the beginning of life and development.

Of the 4 types of casein, beta-casein is the major type found in nature. There are different beta casein types, but the most common are beta casein A1 and beta casein A2. Certain breeds of cows, such as Friesians, produce mostly A1 milk, whereas other breeds, such as Guernseys, as well as sheep and goats, produce mostly A2 milk. Milk produced in Australia and New Zealand is normally a mix of A1 and A2 milks. Remember that it’s the dangers of milk and how it’s implicated in heart disease, breast and prostate cancer, asthma, diabetes, autism, arthritis, and a host of other degenerative diseases that is the real issue.

NOTE: Be aware of the A1-A2 Milk Issue. Evidence is mounting that casein from A1 milk presents a health risk. This may be due to the metabolic byproduct (opioid peptide) called beta casomorphin, which has been linked to brain disorders and disease particularly among babies and infants. The majority of U.S. dairy products are from A1 milk unless stated that they’re produced from A2 milk such as of Guernsey or Jersey cows. European dairy products, however, (which include French, Swiss and Italian cheeses) are mostly derived from A2 milk. The truth is that even A2 cows like Guernsey produce about 50% A1 milk. If there is a problem with A1 milk, most likely the same problem will apply to A2 milk as well. So if the A1 milk risk exists, it will apply to all kinds of casein products.

Human milk contains a wide variety of proteins that contribute to its unique qualities. Many of these proteins are digested and provide a well-balanced source of amino acids to rapidly growing infants. Some proteins, such as bile salt–stimulated lipase, amylase, β-casein (beta casein), lactoferrin, haptocorrin, and α1-antitrypsin, assist in the digestion and utilization of micronutrients and macronutrients from the milk. Several proteins with antimicrobial activity, such as immunoglobulins, κ-casein, lysozyme, lactoferrin, haptocorrin, α-lactalbumin, and lactoperoxidase, are relatively resistant against proteolysis (breaking down of proteins by enzymes) in the gastrointestinal tract and may, in intact or in a partially digested form, contribute to the defense of breastfed infants against pathogenic bacteria and viruses.

Prebiotic activity, such as the promotion of the growth of beneficial bacteria such as Lactobacilli and Bifidobacteria, may also be provided by human milk proteins. This type of activity can limit the growth of several pathogens by decreasing intestinal pH. Some proteins and peptides have immunomodulatory activities (eg, cytokines and lactoferrin), whereas others (eg, insulin-like growth factor, epidermal growth factor, and lactoferrin) are likely to be involved in the development of the intestinal mucosa and other organs of newborns. In combination, breast-milk proteins assist in providing adequate nutrition to breastfed infants while simultaneously aiding in the defense against infection and facilitating optimal development of important physiologic functions in newborns.

As you can see so far, there are many types of proteins that are available in mammalian milk and each species has a different composition of proteins in their milk for different purposes according to the species needs. Additionally, these proteins are only available to nutrify a newborn mammal for a short amount of time helping it reach a specific growth level so that it can become independent from it’s mother and survive in its habitat.


Where can Casein be found?

Casein can be found in a myriad of food stuff and that includes “Vegan” foods. Since milk is essentially “Liquid Meat” it has the same negatives associated with it as any other animal product. It’s important to read the labels on all products you buy to ensure they are truly Vegan and healthy.

Here is a list of things caseins and caseinates can be found in:

  • Soups and gravies, whipped toppings Ice creams & frozen desserts
  • Some coffee creamers Whipped toppings
  • Soy or rice cheeses Baking goods
  • Yogurts Spreads
  • Infant foods Pasta
  • Meat products Many cosmetics
  • Hair preparations Beauty masks
  • Some pharmaceuticals Adhesives/glues
  • Paints Plastics
  • Paper coatings Concrete
  • Textile fabrics Used to clarify wine
  • Common ingredient in protein products like powders, bars, and Sports drinks

Be aware of the term, “non-dairy.”


This is designed to mislead you into believing that the product in question is milk-free. It’s actually a term the dairy industry invented to indicate the product contains less than 0.5 percent milk by weight. People like melting cheese yet want to be dairy free and casein helps non-dairy cheese melt. Conversely, it also makes it harder to wash the stuff off your dishes. The picture above is an example of Almond cheese that’s supposed to be Vegan but contains casein. Technically, this is not a Vegan product and can lead to health issues.

Please read labels.

“A cup of cow’s milk contains about six grams of casein,” writes Barnard. “Skim milk contains a bit more, and casein is concentrated in the production of cheese. A one-ounce slice of cheese holds about 5 grams of casein, and each of those grams holds millions of individual casein molecules…….The problem with milk is not simply its casein–that’s the part that produces the casomorphin opiates. The nutrient” package” in milk–loads of sugar (lactose), animal protein, and fat–triggers the production of IGF-I in the body, and that may be the reason it is linked to certain forms of cancer.”

~Breaking the Food Seduction, Dr. Neal Barnard

Let’s Get High

Digestion of casein by humans results in several chemicals, including casomorphin, which is an opioid peptide that can pass the blood brain barrier and affect the pleasure centers of our brain and gut, just like morphine. Adult humans are incapable of completely digesting casein since the rennet needed is no longer produced after 1-2 years of age. The addictive power of cheese in particular may be due to the fact that the process of cheese making removes water, lactose, and whey proteins so that the casein is more concentrated. So we crave dairy, especially in cheese, because we are addicted to it. No wonder we are reluctant to give it up!

Do you think you could never give up cheese? Besides giving it up for your health, here an additional reason that might help you make the effort: Removing yourself from the involvement in the horrors of dairy production.

If you would like to learn more details about how casein products are manufactured please look for next weeks article for all the details!