We received a question from a reader named Linda about milk protein ingredients and lactose intolerance. “I am highly lactose intolerant as shown by the hydrogen breath test (one of the highest they’d ever tested), so I read a lot of labels. Can you tell me if there is lactose in whey, casein, caseinate or any variation of that?” That’s a good question, since the answer is a little more nuanced than you might think.
Are Casein and Whey Safe for Lactose Intolerance?
First, lets do a very quick and basic primer on the chemistry of lactose intolerance. Lactose is a disaccharide made up of two simple sugars: glucose and galactose. Basically, it’s milk sugar. When someone is lactose intolerant, they lack enough lactase enzyme in their digestive system to break down the lactose into simple sugars. The whole carbohydrate then passes through, and can cause digestive distress (aka lactose intolerance symptoms).
Casein and whey are two major types of proteins found in milk. They are protein molecules while lactose is a sugar molecule. In other words, they are separate components in milk that can be isolated from one another. So in theory, someone who is lactose intolerant (and not allergic to milk proteins) should have no issue with isolated casein or whey milk proteins. But there are some caveats to consider when reading food labels.
Casein and Lactose Intolerance
Casein is the most abundant type of protein in milk. Four types of casein make up about 80% of the proteins in cow’s milk. The majority of people with a milk allergy are allergic to casein specifically. Because of its properties, casein is often extracted from milk and used as a binding agent in various products, from food to paint. Caseinates are compounds made from casein that are water soluble, making them easier to use in many applications.
As noted above, casein itself does not contain lactose. It’s merely a protein molecule. But it needs to be completely isolated to be free of lactose. Casein protein powders, for example, might not be 100% isolated, and could contain lactose. And even with isolated casein and caseinates, there is always a risk that a small amount of lactose could remain. Low levels of lactose might not be an issue for most people who are lactose intolerant, but could be a problem for people who are highly lactose intolerant.
Whey and Lactose Intolerance
The other 20% of proteins in milk are collectively referred to as whey proteins. Like casein, people can be allergic to whey proteins. But isolated whey proteins on their own are protein molecules and do not contain lactose. However, whey is often a bit trickier in our food supply.
As an ingredient, it’s often simply listed as “whey.” If you just bought whey, there’s a good chance it wouldn’t be purified and would contain lactose. In some cases, whey powder can have a very high concentration of lactose. You might see whey listed as whey protein concentrate or whey protein isolate. This sounds like a safer bet, right? Unfortunately, these terms don’t equate to lactose free.
Whey protein concentrate is a protein concentrated form of milk powder. The concentration of whey protein in this ingredient typically ranges from 30% to 80%. The remaining 20% to 70% is primarily made up of lactose, other carbohydrates, and fat. Whey protein isolate is more concentrated, and will usually be at least 90% whey protein. But again, that leaves up to 10% of other milk components, including lactose.
There are highly isolated forms of whey that are processed to remove lactose, but you need to dig a bit to confirm the whey concentration. And of course, trace lactose could still remain. Also, use caution with 100% whey protein powder labels. Sometimes this means that all of the protein in the powder is whey protein, not that the protein used is a 100% pure isolate.
Lactose-Free Casein and Whey Proteins
Of course, you can look for a lactose-free label on the food you are considering. This can be a helpful starting point when considering foods containing casein, caseinates, or whey proteins. But make sure the company understands what lactose-free means and that they have verified their ingredients.
There is no FDA definition or regulation governing the term “lactose-free.” There is a truth in labelling law, but no specific guidance for using lactose-free on labels. Consequently, lactose-free products can still have a small amount of lactose remaining, and many do. This is rarely considered a problem for lactose intolerant consumers, but could be an issue for the highly intolerant.
More Related Topics on Lactose Intolerance
- Lactose Intolerance: A Normal Reason to be Dairy Free
- Does Dairy-Free Whey Exist? Is it Casein-Free?
- What is Lactase? Can it Help with Lactose Intolerance?
- Lactose and Medications
- Should Lactose Intolerant Children Consume Dairy? Understanding the Options
- Is Lactoferrin Dairy Free? Is it Safe for Lactose Intolerance?
For More Dairy-Free Guidance, Get Go Dairy Free!
13 Comments
Hi Alisa, Thank you for all the work you have done in this space. I realized I was lactose intolerant about 13 years ago and just gave up dairy as it was easier back then with very little dairy/lactose free alternatives. I recently started eating a lactose free greek yogurt and lactose free cottage cheese. I am having some allergic reactions and minor digestion issues. Do you have any anecdotal information on adding dairy back in and it not going well? I was never allergic to dairy itself…but now I’m having not so good responses to it, even if its lactose free. ?!? Trying to get more protein in since I only like seafood and eggs. I thought these products could help. Big sigh.
Hi Kelly, there are so many different reasons on why this could happen to someone, and I’ve heard varying cases. Many people think they only have lactose intolerance but they have (or also have) a milk allergy (non-IgE milk allergies occur in the gut, so digestive issues are primary symptoms). For some people, milk allergies develop later in life, and no one really knows why (even if they haven’t been avoiding dairy). For others, after a period of withdrawal, symptoms are more exaggerated or simply more noticeable on reintroduction. These are the main reasons I hear, but the immune system is complicated and not fully understood. It can suddenly react to something without warning, and stop reacting without warning to so many different things. As you know, I must disclaim that this should not be construed as medical advice, and you should speak with a doctor immediately if you believe you are having allergic reactions. This response is based on my own research and experience. On the protein side, seafood and eggs are a great base. Other foods that can help increase protein intake in someone who is unable to consume dairy include proteins powders (made into shakes, bars, etc), tofu and other soy products, whole grains, other beans, nuts, and seeds.
Hi Alisa. I’ve done a food intolerance test through York testing. Scored 20 to cows milk. Earlier I did a hair intolerance test and was told I have an intolerance to milk protein but only when it’s heated? Do you know which protein this would be? Will it be casein? And why is it only when heated? Does the heat change the protein structure?
Hi Neville, studies have shown that some people with a milk protein allergy can tolerate milk when heated to a certain temperature for a minimum amount of time. They have found that this can alter the protein structure – https://pubmed.ncbi.nlm.nih.gov/18620743/. However, I’m not familiar with the opposite – a heated milk intolerance. You would need to ask the testing company if they tested for casein or whey, and what the data is behind there heated milk result. Unfortunately, I can’t speak to their testing, only the company can, and only a doctor can interpret the results and give you a diagnosis.
Thank you for this article. It is very informative and really easy to understand.
My child cannot have casein. He has been prescribed some medication that says it contains lactose. I understand lactose is sugar and casein is protein, what I can’t seem to find the answer to is if something contains lactose will it therefore also contain casein?
Hi Helen, technically, no. If it says lactose, it is just lactose – there shouldn’t be any other dairy components in it. But there is always a risk for trace cross-contamination, which can be a concern with severe and highly sensitive food allergies. Also, some people say they react to pills with lactose when they are allergic. I haven’t found anything to corroborate this (beyond anecdotal).
I am intolerant to gluten, dairy, casein, lactose and soy. This means I need a gluten, dairy, casein, lactose and soy free diet. However, this is not always possible with every meal. These foods are available in most foods.
Casein and lactose are both components of dairy, so a dairy intolerance encompasses both of these. And dairy-free foods should be free of all dairy, including casein and lactose. Fortunately, there are tons of great gluten-free, dairy-free, and soy-free products and recipes. See our gluten-free/dairy-free index for numerous recipe options (most are soy-free) -> https://godairyfree.org/dairy-free-gluten-free-recipe-index and enjoy our product review section, we cover a lot of gluten-free, soy-free products, and all are dairy-free -> https://godairyfree.org/new-dairy-free-product-reviews
I have avoided all dairy products for many years because I get severe headaches after having dairy. Is this considered a dairy allergy?
We have just a little more info on dairy and migraines / headaches in this post -> https://godairyfree.org/health-info/can-dairy-cause-migraines-headaches
There doesn’t seem to be one specific milk related cause. Studies have shown that milk allergies, “sensitivities” (could also be allergies), chemicals in cheeses, or lactose intolerance could be triggers for headaches in some people. Only your doctor could help to diagnose a specific cause in your case.
I am also highly lactose intolerant and find even a very small amount bothers me so I assume that means I should avoid casein? Is there a test to see if you are allergic to casein?
Hi Sandra, there are allergy tests for IgE allergies. Tests for non-IgE allergies are less definitive, so many doctors recommend an elimination diet as the “gold standard.” If you think there is a chance that you are allergic to casein, then you should definitely consult a physician to see what they recommend.