Raw milk is not easier to digest than pasteurized milk, at least not in the way most people mean when they ask. The most rigorous clinical test of this claim found no difference in digestive symptoms between raw and pasteurized milk in people with confirmed lactose intolerance. The reality is more nuanced than either raw milk advocates or critics suggest, though: pasteurization does change milk’s protein structure and microbial content, and those changes cut in both directions.
The Lactose Intolerance Question
Most people searching this topic want to know one thing: can I drink raw milk without the bloating and cramping that pasteurized milk causes? A pilot study from Stanford tested this directly. Researchers confirmed that 16 participants were lactose intolerant through hydrogen breath testing, then had them drink increasing amounts of raw milk, pasteurized milk, and soy milk over separate eight-day periods. Participants logged gas, diarrhea, audible bowel sounds, and abdominal cramping on a 0-to-10 severity scale.
The results were clear. Hydrogen breath levels, which measure undigested lactose, were nearly identical for raw and pasteurized milk. Self-reported symptom severity showed no significant difference across any of the four symptom categories. The worst day for both types was day seven, when participants drank 24 ounces in a single sitting. As the lead researcher, Stanford nutrition professor Christopher Gardner, put it: “It’s not that there was a trend toward a benefit from raw milk and our study wasn’t big enough to capture it; it’s that there was no hint of any benefit.”
The reason is straightforward. Raw milk does contain some bacterial enzymes, but it does not contain meaningful amounts of lactase that survive the acid environment of your stomach. Lactose content is essentially the same in raw and pasteurized milk, and your body has to break it down with the same enzyme either way.
How Pasteurization Changes Protein Digestion
Where raw and pasteurized milk genuinely differ is in protein structure, though the implications aren’t as simple as “easier” or “harder.” About 80% of milk protein is casein, which forms large clusters called micelles. The remaining 20% is whey protein, and this is where heat makes the biggest difference.
The main whey protein in cow’s milk has a tightly folded barrel-like shape that actually resists stomach acid quite well in its raw form. The sites where your digestive enzyme pepsin needs to cut are buried inside the structure. In raw milk, this protein tends to pass through the stomach relatively intact and gets digested further along in the small intestine.
Pasteurization (heating above 60°C) unfolds this protein, exposing those hidden cutting sites. The result is that pasteurized whey protein gets broken down faster in the stomach. Lab studies using simulated digestion have shown that the protein curds formed from heated milk are hydrolyzed more quickly than those from raw milk. So in terms of pure protein breakdown speed, pasteurized milk may actually be digested faster, not slower.
Whether faster protein digestion matters to how you feel after drinking milk is a different question. For most people, it likely makes no noticeable difference. Some raw milk proponents argue that intact whey proteins deliver more bioactive compounds to the intestine, but this hasn’t been shown to translate into a measurable digestive benefit in human studies.
Bacteria, Enzymes, and Gut Health
Raw milk contains live bacteria, including strains with probiotic potential like Lactobacillus casei, Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus paracasei. These are killed during pasteurization. Raw milk also contains active alkaline phosphatase, an enzyme that pasteurization destroys (its absence is actually used as a test to confirm milk has been properly pasteurized).
Alkaline phosphatase is interesting because the version your own intestines produce plays a role in maintaining your gut barrier. It neutralizes inflammatory compounds from bacteria and helps regulate the proteins that keep your intestinal lining sealed tight. Research in cell and animal models has shown that supplementing with this enzyme can protect against increased intestinal permeability, sometimes called “leaky gut.” Whether the amount naturally present in a glass of raw milk is enough to have this effect in humans hasn’t been established.
The probiotic bacteria in raw milk are similarly promising in isolation but unproven as a digestive aid in the context of actually drinking milk. The bacterial counts vary enormously depending on the farm, the cow, the season, and how the milk is handled. A glass of raw milk is not a standardized probiotic supplement, and the strains present may or may not survive your stomach acid in meaningful numbers.
What Raw Milk Does Preserve
Pasteurization does reduce certain heat-sensitive nutrients. Studies on human milk (which undergoes similar pasteurization in milk banks) found losses of about 36% for vitamin C, 31% for folate, 15% for vitamin B6, and 10% for vitamin B12. Cow’s milk undergoes comparable losses. These are real, though milk isn’t a primary dietary source of vitamin C or folate for most adults.
Raw milk also retains higher levels of certain immune-modulating compounds, including specific fatty acids and tiny RNA molecules called microRNAs that are reduced by heat processing. Several large observational studies in Europe have linked raw milk consumption in childhood with lower rates of asthma and allergies. The proposed mechanisms involve anti-inflammatory omega-3 fatty acids, short-chain fatty acids that influence immune cell development, and signaling molecules that may help the immune system learn to tolerate harmless substances rather than overreact to them. This “farm effect” is one of the more compelling areas of raw milk research, though it relates to immune development rather than digestive comfort.
The Safety Tradeoff
Any discussion of raw milk digestion has to acknowledge why pasteurization exists. Between 2009 and 2021, 143 disease outbreaks confirmed or suspected to be linked to raw milk consumption were reported to the CDC. The pathogens involved include Salmonella, Campylobacter, E. coli, Brucella, and Cryptosporidium. These infections can cause severe gastrointestinal illness, and for young children, elderly people, pregnant women, and anyone with a compromised immune system, the consequences can be serious.
A Salmonella outbreak traced to commercially distributed raw milk in California spread across five states between September 2023 and March 2024, illustrating that even regulated commercial raw milk carries risk. Pasteurization eliminates these pathogens reliably, which is why it became standard practice in the first place.
What This Means for You
If you’re lactose intolerant and hoping raw milk will solve your symptoms, the clinical evidence says it won’t. Your discomfort comes from insufficient lactase production in your own intestine, and nothing in raw milk compensates for that. Lactase supplements, lactose-free milk, or fermented dairy like yogurt and aged cheese (where bacteria have already broken down most of the lactose) are more reliable options.
If your digestive issues with milk aren’t clearly lactose-related, the picture is murkier. Some people report feeling better with raw milk, and it’s possible that differences in protein structure, bacterial content, or other bioactive compounds play a role that current studies haven’t captured. The Stanford study was small, and it only measured lactose-specific digestion. But the strongest and most testable claim about raw milk and digestion, that it helps with lactose intolerance, does not hold up under controlled conditions.