Milk proteins: The good and the bad

By May 6, 2015 May 12th, 2015 Nutrition
milk proteins

Remember Little Miss Muffet, eating her curds and whey? These are the two proteins found in milk. Whey protein is the thin liquid part of milk remaining after the curds—called casein—are removed. But not all casein is the same.


The curds from milk are used for most cheese making. Cottage cheese is the best example of what curds look like. However, the curd, casein, is the protein in milk most people are allergic to when there’s a dairy allergy. Newborns and young children are especially vulnerable to curds because their intestine and immune system is too immature to tolerate this protein.

But not all casein is the same.

Most of the protein in milk is casein, but there are different kinds. The two most common ones are A1 and A2 beta casein, and they have very different affects on our health. A1 has been associated with ill health and disease, but A2 has not. If you consume dairy products, it’s important to purchase those made from milk with little or no A1.

Most people think of black and white cows as the source of their milk. These animals, called Holsteins (the U.S. breed) and Friesians (the European version), are the most common sources of milk on the market. These large, high volume milk producers are most commonly used by big corporate dairy farms. They are typically given bST (bovine somatotropin—a hormone used to increases the cow’s milk production), and provided with special feeds of corn and synthetic vitamins rather than grass. These cows produce milk that contains higher amounts of beta-casein type A1, a protein that behaves like an opiate and has been associated with chronic illness. (Reddish colored cows, including Ayrshire and Milking Short Horns, are also in this category and less common.)

The other types of dairy cows are smaller, and brownish and white in color. These are called Jersey, Guernsey, and Brown Swiss cows. They produce lesser volumes of milk, are naturally resistant to disease, and convert grass to milk quite efficiently. The level of A1 casein in these animals is very low, and they have higher levels of A2. Their milk is similar to that of other animals including goat, sheep, buffalo, yaks, donkeys, and camels—milk from these animals contain mostly A2 and little A1.

Research shows a strong association between the consumption of A1 casein and various health problems. Numerous studies, including data from the World Health Organization (WHO), have linked A1 with increased risk of heart disease, high cholesterol, type 1 diabetes, sudden infant death syndrome, and neurological disorders, such as autism and schizophrenia, and possibly allergies. But these health issues are not associated with consumption of A2 casein.

How can you tell which type of animal your milk comes from? Unfortunately, in most cases, the milk from many different herds of cows are mixed by the time it gets to the store as milk or cheese. This makes it impossible to tell what you’re getting regarding the kinds of casein it contains.

Short of going to the farm to buy raw milk, and seeing the types of cows there, which a surprising number of consumers can do, you will soon have more access to milk higher in A2 and low (or no) A1. New Zealand public company, A2 Corp, LTD, licenses technology that identifies milk with the A2 beta casein protein. The company also sources and supplies A2 milk, with operations primarily in New Zealand, Australia, and now the United States (with plans to soon enter the Asian market).


The milk containing most of the vitamins and minerals, including calcium, and also is a complete protein, is whey. During the making of cheese, which mostly is produced from curds, whey is often fed back to the animals for nutritional reasons. However, making whey cheese is great option—the one most people are familiar with is ricotta. When buying it, check the label and make sure whey, not curds, is the main ingredient (many cheap ricotta products are made with whole milk and not whey). Whey is also made into powders for use in baked goods and smoothies.

The whey component of milk contains a group of natural sulfur-containing substances called biothiols that help produce a key antioxidant in your cells called glutathione. Because it helps the immune system, whey has been used to help prevent and treat many chronic conditions, from asthma and allergies to cancer and heart disease. It can also help improve muscle function. Most people who are allergic to cow’s milk can usually consume whey without problems. Small amounts of lactose are found in whey (much less than is found in liquid milk) but this is usually too little to cause intestinal problems, even in most people sensitive to lactose. In those who are truly lactose-intolerant (probably less than five percent of the population), this amount of lactose could be a problem.

Most importantly, always buy organic to avoid the chemicals, hormones and drugs commonly used in the dairy industry. I don’t consume milk, but instead buy raw milk to make cultured raw milk cheeses, and butter.

When buying cheese, look for raw milk varieties. Those with inflammatory conditions, and other problems associated with an imbalance of fats, should restrict dairy until health is restored. Maintaining a balance of fats, as discussed in my books and on this website, can be accomplished while consuming healthy dairy products in moderate amounts.


  • Shirley says:

    Hi, I am not going to add to the debate, but wanted to say that I came here via an internet query about curds and whey and I am so glad that I did. In many ways I agree with everyone, on one level or another. Although it is possible to get calcium from non-dairy sources, it is also true that dairy does contain very high levels of this very important nutrient. I do believe that we should use A2 milk if one chooses to drink milk. I do myself, but recognise it is a very personal issue and would counsel everyone according to their needs and or belief. The debate back and forwards here is wonderful. I am a qualified Naturopath and Nutritional Medicine practitioner, and it is lovely to read many very passionate and also well-informed respondents. Thanks so much. Shirley

  • Autumn says:

    I recently found out I have a casein intolerance. It scored a 20 on my blood results.
    I found to like goat cheese, I plan to use it on sandwiches/dinner foods. I also found a buffalo mozzarella cheese that is flown in from Naples,
    Italy. I have not tried it yet, was hoping someone would get back to me before I open it.
    It’s ingredients are pasteurized buffalo’s milk, natural cheese culture, salt, rennet.
    The company, fattorie garofalo, explains the water buffalo are treated very well and that the company has the
    DOP certification. Was hoping to put on all my Italian dishes.
    Any thoughts???

    • Paul W. says:

      Thank you for this link. Best thing I’ve read on Casein and its non-existent role in causation of Coronary heart disease or Diabetes

  • Milind says:

    I came here searching for “why commercial manufacturers of whey protein don’t use buffalo’s milk”. Though I did not get any answers, I find the mention of A1 & A2 milk disturbing. I don’t know which cows we have in India, but everyone uses Oxytocin injection to increase the milk output. Till date I have not seen any protein manufacturer mention whether their milk was sourced from A1 or A2 variety. I don’t know about US regulations, but looking at your text I feel it should be mandatory.
    Anyway, I googled but still have not found the answer to my query. If anyone has any link, please share.

  • Richard says:

    It is such a stupid argument to say this or this food is creating acid in the stomach. It simply shows the lack of knowledge of the writer.

    Stomach produces Hydrochloric acid and it is the main process of this part of the digestive tract. Whether your milf or whatever food is acidic or neutral or even basic, it will become very acidic in the presence of the secreted hydrochloric acid at a pH of 2.

  • Celestine Nicolas says:

    Dear All, particularly Nicole,
    My mother (back in 1939) didn’t bring me up on cow’s milk for the reason you give i.e. that cow’s milk is meant for calves and not for human babies, let alone adults. She was proud of the knowledge, as if she had found the answer to all human ills. When I mentioned this to an Ayurvedic doctor (Hindu) the first thing he answered was – Hey, why do you think we Indians consider cows holy? The fact is, humans are ABLE to milk cows and a cow naturally produces more than her calf needs. The modern world has forced farmers to breed cows that produce an excessive amount of milk (not good for the cow’s health) and the fact that that they are often not grass fed has caused damage to the idea that milk can be nutritious. There is no other animal, to repeat the words of the Hindu doctor, that has four stomachs with which to predigest grasses and other plants so that we humans (and animals if they have the chance) are able to get any nourishment out of grasses at all. I assure you that every dog and cat I know is wild about all milk products and would milk a cow if the cow would let them. Hedgehogs have been known to milk cows at night while they are lying in the fields. So perhaps do other animals. I happen to have a cat (that got dumped on me because it was so sick) that is better off on milk products (including cream) than any commercial cat food. This doesn’t mean that he’s supposed to live on milk products, however. Cats are meant to eat mice: (a tiny mouse heart has at least 10 times the amount of taurine as a chicken heart and cats can’t live without taurine, that’s why they’e obligate carnivores). Neither are we meant to live on milk products after the age of three. But we don’t usually as we eat fruits and vegetables and legumes, if not fish and meat, all of which most of us are fine with. But don’t forget that our soil is depleted and fruits and vegetables lack what they used to provide us. So – yes – go find yourself a brown cow (type 2) that eats only grass and wild plants in a wild field and try its milk!

  • Marco says:

    Thanks for your reply, it makes sense. However are cow cheese and cow yogurt still healthy? Or should we try to avoid all cow milk related products ?

    • Marco:

      It’s not a big deal as long as you consume it in moderation. That said, if you’re looking for optimal health, then yes, avoid cow’s milk and head for goat’s milk. But that doesn’t stop me from eating cheddar cheese (from cows). How far you want to take this is up to you.

  • Marco says:

    I’m a bit confused about whether milk is good or not. I’ve always been told that drinking milk is good for health but according to what I can read here, it appears it is not entirely true. Everyday I eat one yogurt (either in the morning or in the evening) and I drink one glass of milk before going to bed. Is that fine? Otherwise how can I improve this?

    • Marco:

      Think about it this way: the prevalence of milk cows that produce mainly A1 casein (the “bad” kind, in shorthand) is relatively new. When the culture of drinking milk—from which you get advice such as “drinking milk is good for health”—was in its inception, milk cows that produce the “good” kind of casein were much more prevalent. So, drinking the kind of milk that the saying is intended to refer to (because back then there was little to no “bad” milk), is extremely healthy. The problem is that the type of milk changed but the culture didn’t.

      The easiest way to solve this? Start drinking goat milk, goat cheese, goat yogurt, etc. (I say goat because I don’t expect there to be much yak or camel milk at your local supermarket or health food store).

  • Caleb West says:

    I am a 22- year old college athlete with a low budget and a busy schedule. I shop at Wal-mart. I’m sure that is the worst place by health-nut standards to search for the best kind of food, but that’s where I go. However, I do try to eat healthy and I avoid sugar and processed flour during training. I really want to try to the Maffetone test and de-tox myself for two weeks, but so far I have not found a list on this site of specific foods I could find at my local grocer that meet the Maffetone standard. I have questions such as: Could I eat canned tuna? Is greek yogurt OK? Or, what brands generally pass the Maffetone test?
    I guess my biggest question is this: Does everything I eat during the 2-week Maffetone test have to be 100% sugar free, organic, in-season and unprocessed?
    or will I fail to de-tox myself in two weeks if I eat the wrong kind of tuna?
    I appreciate the effort put in to educate us about eating right. Thanks for your help.


    • Caleb:

      This is an excellent question. The best way to answer it is this: the more real foods, and unprocessed, the better. Generally speaking, Greek yoghurt is OK, just make sure that it is labeled “unsweetened” and has no added sugar. Be thorough: A couple of times, I bought yoghurt labeled “plain” by an organic brand that had added sugar in it.

      You won’t “fail” the detox if you eat the wrong kind of tuna. The most important thing is to stay away from high-glycemic foods (and foods with added sugar). That’s #1. Do your best to stick to realfoods. In an ideal world, that’s what you want. But we don’t live in an ideal world.

  • […] Casein protein is also derived from milk, but it is absorbed much slower. It has a complete amino acid profile just like whey protein and bodybuilders often use it before bedtime to boost protein synthesis in their sleep. Casein is much more allergenic than whey and can cause issues in people who are sensitive or allergic to dairy. There are different types of casein and some types are linked to increased risk of heart disease, high cholesterol, diabetes and neurological disorders, such as autism and schizophrenia. (1) […]

    • Nicole says:

      Hi Ivan, from a nutritionists point of view, the consumption of animal products , regardless of which view it may be from, social, or nutritional, are not designed to be consumed by mankind; meat or milk. The key reasons our bodies and our planet are both breaking down, literally speaking, is because of the consumption of dairy and meat; pasteurised, cured, or not. Cancer, Alzheimer’s, Diabetes, Cardiovascular Disease, the list goes on. These diseases are all products of a modern day world, our polluted environment, and from the consumption of animal products.

      • Nicole:

        Thanks for your comment. Did you not mean to say that the ills of our planet are because of the way that meat and dairy are produced? Surely the consumption of hunted and fished animals in modest amounts did not produce the same assortment of ills, physiological and environmental?

      • James says:

        I’ve read Christopher Mcdougall book Natural Born Heroes and he basically states that we ARE designed to eat animal products and plants but it is processed grains and sugars that are the real enemy.

        • James:

          I agree with you completely.

          That said, I would address this issue differently: the question of “design” and “intention” is a toughie to address. And it really depends on how we frame it too: many people question whether, for example, we should run on asphalt or concrete, because we weren’t “designed” with asphalt or concrete in mind. But the fact of the matter is that we were designed with terrain of varying hardness and smoothness in mind. Because we were designed for variation and adaptability (within reason) rather than particular situations, it’s a much easier claim to make that we are perfectly capable of running on asphalt or concrete regardless of whether evolution specifically accounted for the possibility that we might be running on surfaces comparable to asphalt or concrete.

          Similarly, we need not have been expressly designed to eat animal products for it to be within what we are capable of. That said, when you look at the evidence, you see that dedicated plant eaters are quite capable of producing an array of essential, fat-soluble vitamins and nutrients that are only found in animal fats. We are not. By all indications, it seems that evolution supposed that there were going to be animal-sourced vitamins in our diet, and didn’t instill in us an ability to synthesize them. In that account, we are designed to go out and partake of animal products.

          And when you include the many features we share with predators and scavengers (who, it should be noted, only predate and scavenge animals), not to mention the architecture of our digestive system, the evidence becomes overwhelming. And it just keeps growing: Hunter-gatherers should be referred to as gatherer-hunters: they get 80% of their calories from foraging, and only 20% from hunting. The thing is, hunting is a colossal energy expense as compared to foraging: It makes no economic sense that an animal would spend 80% of its energy getting 20% of its calories unless there was something in those calories it needed really badly. Furthermore, it makes no sense that evolution would have selected for the hunting behavior, hunting proclivities, and hunting culture themselves unless there was a deep economic need underlying it.

          And when you look at the fact that we’re missing the ability to synthesize certain vitamins—an ability that is present in ruminants and other dedicated plant-eaters—this economic hypothesis starts being more and more justified.

    • Paul says:

      Hi Ivan,

      Do you have a recommendation for organic whey that I can buy?


  • Neil says:

    There is another reason for watching your milk intake, and that is the risk of consuming too much calcium.
    Thomas Levy, in his 2013 book Death by Calcium, presents recent evidence of the dangers. Roughly speaking, supplementing by 500 mg of calcium per day, will increase you risk of heart attack and stroke, by between 20 – 30%.
    My own warning signs came from consuming about 700 – 1000 mg of calcium daily from my loving New Zealand made milk from pastured animals with an organic philosophy by the farmer. A few years of this found me with quite sore muscles after little exercise……..bad enough to cost me a weeks skiing and that weeks rest was not sufficient for a good recovery.
    Having a wish for better health and fitness, including bone health, I have virtually ceased my daily consumption of milk (and cheese) while ensuring a good supplementation of magnesium and Vitamin C.
    (A 70’s retired psychologist with a passion for skiing and sailing)

    • Nicole says:

      Neil, I just wanted to quickly write to you and say that I don’t think it was the intake of calcium that was the problem. When we eat dairy products, it creates acid in our stomachs and to neutralise or create an alkaline state within us, Vitamin C is drawn from our bones to do the job. Calcium is good for us, we need it along with Vitamin D & C for strong bones and a healthy body. But it’s best to obtain any source of calcium from nuts and what nature provides us with, rather than what we can obtain from another living animal.

      • Nicole:

        I absolutely agree. That said, keep in mind that raw, grass-fed, unpasteurized milk is (or should be) alkaline.

        • Nicole says:

          Hi Ivan, thanks for your reply. Even though raw milk, like pasteurised, may be an alkaline outside of the human body, once consumed, it is still acidic, just not as much as pasteurised milk. Humans are designed to drink their mothers milk until they are weaned. Human milk is perfect for humans. Cows milk is perfect for cows. We are the only species that drinks another species milk. Our education system has engrained this into us from day one that it is normal to drink another animals milk. But it’s pretty weird, if you think about it!! Imagine humans drinking cats and dogs milk or vice versa. It’s not natural.

          • Nicole:

            Maybe raw milk is acidic inside the body (I didn’t know). But it’s calcium content is still far more available than the calcium in pasteurized milk.

            As far as the “natural” argument goes, I would caution you against it. In principle, what’s the difference between one animal’s milk and that same animal’s meat, particularly for populations that do not lose lactase production towards adulthood? Both are acidic. And what is the difference in principle between a plant such as corn or wheat as opposed to a plant that must be fermented for the majority of its nutrients to become bio-available to humans (soy)? Is one more “natural” than the other?

            If I think about honestly, it just so happens that we don’t drink cats’ or dogs’ milk just like (in the US) we don’t habitually eat cats’ or dogs’ meat. For example, I find it odd enough to drink goat’s milk that I pass it over in the supermarket, and being even less inclined to drink cats’ or dogs’ milk is simply an extension of what I’m used to. Just because our society tells us it’s okay to drink a particular animal’s milk (and that it’s not okay to drink another’s) is not an argument against drinking milk, particularly when the argument against drinking milk was initially made on nutritional grounds and not social grounds.

            We shouldn’t re-frame the nutritional argument of human milk vs. animal milk as a societal one of animal milk 1 vs. animal milk 2.

          • Mike Irby says:

            The natural argument might sound good but which of us really eats a “natural” diet. A natural diet would mean only eating fruits or vegetables in season. Fruits and vegetables are only harvested during a short season and spoil rapidly. A “natural” diet would mean spending at least half the year eating nuts, winter squashes, tubers and the like… Meat is a great winter “crop” because the weather is cool or cold and the meat is preserved by the cold. That is when we need the most fat for energy. If you want to eat natural turn off your fridge and freezer and only eat what is in season locally. Me, I choose the eat all things, I wish I was better at moderating my intake but that is a constant battle against my “natural” instincts. I believe it is the massive amounts of sugar, processed grains and meats that cause the health issues we face. If we are not designed to eat meat explain the diets of the Inuit… I have enjoyed the wide array of thoughts and ideas in this conversation. Just wanted to add mine for what they are worth. Thanks.

    • jo says:

      A2 Milk Company milk finally hit our market. I bought it immediately and, most likely due to ultra-pasteurization could not drink it. I contacted the company regarding the ultra-pasteurization and received a letter back stating that they are new and expect to be changing things in the future but they did not address the pasteurization issue. I went back to Jersey milk and goat milk. For cheese, it’s sheep, goat or cheeses from France. I’m wondering about whey protein. Is it okay to eat or drink? Some of my vitamins have it. Does whey protein contain A1 Beta Casein?

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