- What is casein?
- Casein strains the digestive system
- Is casein bad for health?
- A1 and A2 beta-casein variants
- Does goat milk have casein? What about sheep milk?
- What's in our milk?
- Taste test: Sheep milk vs cow milk vs goat milk
- Verdict: Is sheep milk yogurt better than goat milk yogurt?
- Yogurt brand comparison
Pouring a bowl of cereal, dunking a cookie, or flavoring your coffee has become increasingly difficult with all the new dairy choices gracing the shelves of the grocery store. Macadamia, almond,oat, cow, goat, sheep, and infinitely more muddy the decision process on which milk is best for whatever your milk needs are. Well let’s start by breaking down our animal dairy products, and which is best for you?
Sheep and goat milk are generally thought to be better for our health than cow’s milk — but why? Although they contain casein, a protein found in all dairy, sheep and goat dairy contain far less A1 beta-casein, the most inflammatory casein found in milk, and far more A2 beta-casein, the easier-to-digest form of casein.
Read along and dive into the details of why casein can be bad for us, how much of it is in the most popular types of milk, plus a sheep-vs.-goat-vs.-cow-dairy taste test!
What is casein?
Casein is one type of protein found in dairy which is responsible for giving milk its white color. Different types of dairy have different types of casein, and other proteins like whey, in varying amounts. Each type of protein found in dairy affects our digestion differently (although some people are sensitive to all of it). One of the ways we categorize customers of the nutrition plans is based on their sensitivity to dairy. You can generally see lactose intolerance in people’s genetic charts.
Cow’s milk, the most commonly consumed milk in America, comprises 3.3% protein, of which more than 80% of the protein is casein while the rest is whey.
Nutritionally, whey is thought to be a better protein source than casein because of its superior amino acid profile — an important factor in determining food protein quality — and it is more easily digested and absorbed. Whey is what is recommended for infant milk formula and is often found in nutritional supplements.
Casein strains the digestive system
In sharp contrast to its easily absorbed cousin whey, casein breaks down slowly, putting a strain on the digestive system, and if you believe the authors of “The China Study,” promoting cancer growth. 1 The China Study is actually a series of studies that conclude that eating animal products increases the risk of many diseases. The protein the studies used to evaluate their claims was casein, which is what put this dairy health comparison post on our team’s radar in the first place.
Colin Campbell, author of The China Study, claims that diets rich in animal products such as milk, may be linked to as many as 70% of the cases of colorectal and prostate cancer; 50% of breast, endometrial, pancreatic, and gallbladder cancers; and 20% of lung, bladder, mouth, and esophageal cancers. 2 3
So, The China Study’s stance on dairy is pretty clear: don’t eat it from cows, goats, or sheep. This is corroborated by other health commentators like Dr. Mark Hyman, who wrote this blog post: 6 reasons you should avoid dairy at all costs.
However, not all types of dairy contain the same protein in the same amounts, and some who can’t tolerate cow dairy are able to consume sheep or goat dairy products with very little problems. How can this be?
The proteins are different. It’s important to know if you choose to consume dairy that there are several types of caseins in the milk of farm animals, α-s1, α-s2 , ß, and κ, each with their own properties and purpose. 4
The variations in casein percentages among animals can be drastic — casein makes up 80% of the total protein in cow’s milk versus only 55% of total protein in horse milk, for example — and the levels of the types of casein can even vary depending on the breed producing the milk. 5
Finally, the production process in dairy matters. Casein and whey are found in milk, yogurt, cheese, and ice cream, though in many cheeses, the casein is coagulated to form the curd while the whey is drained.
Is casein bad for health?
Some feel very strongly that it is. Others disagree, and to be fair, there probably hasn’t been a dispositive study performed yet as studies like The China Study are based on population level questionnaires. Rather than proving a causal relationship, they establish correlations between variables.
However, there is reason for some concern. T. Colin Campbell and his team showed us that tumor growth in rats increased when fed a diet containing more than 10% casein, and shrunk when the dietary casein levels fell below 5%. 6
While The China Study wholeheartedly advocates for a plant-based diet and total removal of dairy and other animal products, let’s take a look at the type of casein that may be the biggest problem — genetic variants of the beta-casein — and whether cow, sheep, or goat dairy share the same levels of the same types of caseins.
A1 and A2 beta-casein variants
Casein protein What it does
A1 beta-casein Releases beta-casomorphin-7 during digestion, which has been linked to type 1 diabetes, heart disease, infant death, autism and digestive problems
A2 beta-casein Different from A1 beta-casein by one amino acid and generally thought to be safe; most commonly found in cows in Africa and Asia
A1 beta-casein seems to be the worst
The beta-casein in mammal milk has two variants, A1 and A2. However, A1 beta-casein is the only casein that creates beta-casomorphin-7, a naturally occurring opioid peptide and direct histamine releaser that can be a risk factor for heart disease, type 1 diabetes, and sudden infant death syndrome. 7 When breeds of cattle in a particular region don’t change for over 50 years, heart disease mortality rates have correlated with the consumption of A1 beta-casein. 8
In another study, infants fed with formula containing cow milk during the first three months of their life showed a delay in psychomotor development and heightened muscle tone. Breastfeeding over artificial feeding (with A1 beta-casein cow’s milk) may reduce the risk of delayed development and related disorders, like autism. 9
Digestion of A1 beta-casein, at the least, can lead to some adverse gastrointestinal effects that resemble lactose intolerance. In one double-blind study, 45 subjects drank milk with both variants of casein, along with milk that only contained A2 beta-casein. 10
Compared with milk containing only A2 β-casein, the consumption of milk containing both β-casein types was associated with significantly greater PD3 [post-dairy digestive discomfort] symptoms; higher concentrations of inflammation-related biomarkers and β-casomorphin-7; longer gastrointestinal transit times and lower levels of short-chain fatty acids; and increased response time and error rate on the SCIT. Consumption of milk containing both β-casein types was associated with worsening of PD3 symptoms relative to baseline in lactose tolerant and lactose intolerant subjects. Consumption of milk containing only A2 β-casein did not aggravate PD3 symptoms relative to baseline (i.e., after washout of dairy products) in lactose tolerant and intolerant subjects.
It can be hard to get away from casein. How do you know if the cow’s milk you’re consuming has A1 beta-casein? Milk from cows with the A1A1 genotype of beta-casein represents the main source of beta-casomorphin-7 (the bad stuff). Be sure to also check your nutrition labels: Casein may be lurking in your protein supplements and non-dairy food, as it is used as a whitener or thickening agent.
Knowing how and where the cow was raised is a start, but is not practical for most of us. The most effective way to avoid A1 beta-casein is to consume other types of milk.
Does goat milk have casein? What about sheep milk?
Yes, there is casein in goat and sheep milk, but not in the same form as cow milk. Sheep and goat dairy contain much less or no A1 beta-casein; instead, they mostly contain the more easily digestible A2 beta-casein, which is a big part of the reason they’re thought to be healthier.
What are some of the other nutritional differences between sheep’s, goat’s, and cow’s milk? The following chart details some of the major components of the three types of milk.
What's in our milk?
Cow (whole milk) Goat Sheep
Carbohydrates 11.3g 10.86g 13.13g
Fat 7.93g 10.10g 17.15g
Protein 7.86g 8.69g 14.65g
Vitamin D 98 IU 29 IU not determined
Calcium 276mg 327mg 473mg
Lactose 12.83g not determined not determined
Cholesterol 24mg 27mg 66mg
Fatty acids, total saturated 4.551g 6.507g 11.277g
Histidine 0.183g 0.217g 0.409g
Cow, sheep, and goat milk all have the same ratio of casein to whey protein (80:20). Sheep milk is actually highest in casein and whey, in addition to fat and total solids. 11
It’s all about genetics. Goat milk and sheep milk have similar amino acid sequences, both of which are different from cow’s. And the biggest difference between sheep and goat milk is the higher proportions of low-chain fatty acids; lactose is also slightly higher in goat milk than sheep milk. The fatty acids in goat milk, however, make it easier to digest over both cow and sheep dairy. It takes about 20% less time to digest goat’s milk over cow’s milk because of the size of its fat globules. 12
Like cows, composition of goat’s milk varies between breeds and regions, but because of the lack of or much lower amount of A1 beta-caseins — along with another inflammatory casein type, alpha(s1)-casein — goat and sheep milk may be good alternatives for children who are allergic to cow’s milk or adults avoiding it for health reasons. 13 14Goat milk also has higher levels of essential amino acids than cow milk and can help manage high cholesterol. 15
However, if you’re sensitive to cow’s milk, switching to sheep or goat’s milk may not solve everyone’s allergy problems. 16 There is a high risk of cross-reactivity with cow’s milk, so children and adults should explore goat’s milk with caution. Most children who are allergic to cow’s milk are sensitive to whey protein or casein and may therefore also be allergic to goat’s and sheep’s milk. 17
Taste test: Sheep milk vs cow milk vs goat milk
For this taste test, John, GeneFood’s founder, wanted to check out some of these other types of yogurts he has heard about. Did you know that there are a dozen styles of yogurt? Coconut milk, almond milk, cashew milk, soy milk, whole cow’s milk, and more.
John tried three new brands to compare to one of his standbys, Chobani. To keep the playing field relatively even, he went with vanilla flavor on each and opted for 0% milk fat (cow) when possible.
To know what you’re getting into in terms of ingredients, yogurt must have an 8.25% solids content, not fat, to be considered yogurt in the U.S. Nonfat dry milk may be added to increase the amount of solids or cream to adjust the amount of fat, while stabilizers like alginates, gelatins, gums, pectin, and starch may be included to help prevent the separation of whey or increase firmness. Starter cultures ferment the lactose in milk to produce lactic acid, causing the milk to clot and form yogurt.
Special note: Many yogurts contain live active cultures of histamine-producing bacteria, such as L. Casei. If you already have allergy issues, these can up your histamine intolerance, as John discussed in this mega post.
1. Siggi’s Icelandic style cow milk yogurt
Stats: Siggi’s 0% milkfat, strained nonfat yogurt, all natural with milk from grass-fed cows, produced without the use of rBST growth hormone. No aspartame, sucralose, gelatin, artificial colorings, preservatives, or high-fructose corn syrup.
Nutrition: 110 calories, 15g protein, 9g sugar.
Ingredients label: Pasteurized skim milk, organic agave nectar, Madagascar bourbon vanilla, fruit pectin, live active cultures.
Price: $1.69 for 5.3 ounces.
Taste: “Siggi’s was really good. I would definitely eat this on its own and not waste it in a smoothie! The Madagascar bourbon vanilla was pronounced but not overwhelming, and was actually visible in the yogurt. The yogurt had a nice texture, too. I kind of hate when you lift a yogurt lid and there’s water on top, prompting you to stir before eating. Siggi’s was thick, smooth, and creamy. Delicious. I particularly love that it had SO much protein, which is the main reason I have bought Greek yogurt over any other kind.”
2. Redwood Hill Farm goat milk yogurt
Stats: Redwood Hill Farm goat milk yogurt, certified humane raised and handled, certified kosher, gluten free. Grade A yogurt, cultured slowly with seasonal variations in texture.
Nutrition: 140 calories, 5g protein, 13g sugar.
Ingredients label: Grade A pasteurized whole goat milk, organic cane sugar, organic vanilla extract, tapioca starch, pectin, live active cultures.
Price: $2.39 for 6 ounces.
Taste: “I’d never had goat’s milk yogurt before and was a little nervous I wouldn’t like it. The taste is pretty similar to goat cheese — tangy, but much lighter! The texture was pretty smooth, though a little watery for my taste. The vanilla is present, but the goat’s milk flavor itself overrides it. I’m curious as to what this would taste like with other flavors. I ended up eating it with some grapes, and it tasted even better. I’m a little bummed at how much sugar there was versus protein, though.”
3. Bellwether Farms sheep milk yogurt
Stats: Grade A sheep milk from a family-owned farm and creamery, full-fat probiotic yogurt with 12 live, active cultures. Made with Madagascar Bourbon and Indonesian vanilla beans.
Nutrition: 170 calories, 10g protein, 9g sugar.
Ingredients label: Pasteurized sheep milk, cane sugar, vanilla extract, vanilla bean, live active cultures.
Price: $2.19 for 6 ounces (on sale at Whole Foods from $2.49).
Taste: “As soon as I opened the lid, I was pleased to see actual vanilla bean mixed into the texture, which was smooth and less thick than Siggi’s, but not watery. It had a closer taste to cow’s milk than goat’s milk, which I enjoyed because it felt more familiar, but still had that differential tang. It was more like Greek yogurt to me. I really enjoyed how mildly tart this was, the texture, and all the great facts associated with sheep milk: more protein and healthy fats, and less sodium.”
4. Chobani Greek yogurt
Stats: Grade A nonfat vanilla blended Greek Yogurt, with probiotics, kosher and gluten free. No rBST or artificial preservatives; only natural non-GMO ingredients.
Nutrition: 110 calories, 13g protein, 13g sugar.
Ingredients label: Nonfat yogurt (cultured pasteurized nonfat milk), evaporated cane sugar, water, vanilla extract, locust bean gum, fruit pectin, natural flavor, lemon juice concentrate, live cultures.
Price: $1.19 for 5.3 ounces.
Taste: “It may have been unfair that I tried the Chobani last in this lineup, but since I was used to what I was getting, I figured it couldn’t hurt. The Chobani ended up being my least favorite! Compared to all the others, its flavor felt “off” and a bit boring. Despite the label mentioning only “natural” ingredients, the others felt more … fresh to me. The vanilla taste was fine, but in line with the goat’s milk being bottom tier. It just didn’t do much for me. Probably why I only use it in smoothies!”
Verdict: Is sheep milk yogurt better than goat milk yogurt?
Determining the best type of milk to drink or yogurt to eat is all up to the individual, though studies have shown that the casein in cow’s milk can be dangerous. Even if you’re not allergic to cow’s milk, it may be best to reduce your consumption. There’s also a whole bunch of bad stuff to be said about Greek yogurt, or more aptly named in the commercial market, Greek-style yogurt and all its additives. (If you’re interested in the process of making Greek yogurt, check out this informative article on “The future of yogurt” published in the American Journal of Clinical Nutrition.)
To that end, here are the winners of John’s taste test!
Yogurt brand comparison
Brand Casein Fat Sugar Taste
Siggi’s Icelandic style cow’s milk yogurt (nonfat) No information on casein from Siggi's, but cows are fed 100% vegetarian diet (mostly grass) and milk comes from farms in Wisconsin and New York 0g fat for 5.3 oz. 9g sugar for 5.3 oz. 4 out of 5 stars
Redwood Hill Farm goat milk yogurt Goat milk is very low in A1 beta-casein and primarily contains A2 beta-casein 5g fat for 6 oz. 13g sugar for 6 oz. 3 out of 5 stars
Bellwether Farms sheep's milk yogurt Sheep milk does not contain A1 beta-casein; also has 60% more protein than other milks 9g fat for 6 oz. Higher in medium- & short-chain fatty acids 9g sugar for 6 oz. 5 out of 5 stars
Chobani Greek yogurt 0% milk fat (cow) No information on casein from Chobani; because of it's straining process, Greek yogurt loses some of the whey, lactose, and sugar found in regular cow's milk — meaning the protein found in Greek yogurt is almost entirely casein 0g fat for 5.3 oz. 13g sugar for 5.3 oz. 3 out of 5 stars