What Diseases Can Milk Cause? Answering Your Health Questions

December 5, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), outbreaks linked to raw milk are disproportionately high relative to its consumption frequency. This highlights a key aspect of the complex question: what diseases can milk cause? Potential health issues range from foodborne illnesses and allergic reactions to digestive problems and chronic inflammatory conditions.

Quick Summary

This article explores the health risks associated with milk, including bacteria in raw milk, the difference between lactose intolerance and milk allergy, links to inflammatory conditions like acne, and potential connections to certain chronic diseases. It also addresses the safety of pasteurized vs. unpasteurized dairy.

Key Points

Raw Milk is a Major Risk: Unpasteurized (raw) milk can carry dangerous bacteria like E. coli and Salmonella, causing severe foodborne illness, especially in vulnerable populations like children and the elderly.
Lactose Intolerance vs. Milk Allergy: These are distinct conditions; intolerance is a digestive issue caused by enzyme deficiency, while allergy is a potentially life-threatening immune response to milk proteins.
Pasteurized Milk is Safe: The pasteurization process effectively kills harmful bacteria without significantly altering milk's nutritional value, making it safe for general consumption.
Dairy and Skin Conditions: Some studies suggest a correlation between dairy consumption and inflammatory skin conditions, particularly acne, although the connection is complex and requires more research.
Chronic Disease Links are Nuanced: The evidence linking dairy to chronic diseases is inconsistent; some studies suggest potential links to certain cancers (e.g., prostate) while also suggesting protective effects against others (e.g., colorectal).
Inflammatory Responses Vary: Dairy can promote inflammatory responses in some individuals, while in others, it may have a neutral or even anti-inflammatory effect, depending on genetics and the type of dairy consumed.

Understanding the Risks of Raw vs. Pasteurized Milk

One of the most significant distinctions in evaluating milk's health effects lies between raw (unpasteurized) and pasteurized milk. Pasteurization is a heating process that kills harmful bacteria, dramatically reducing the risk of foodborne illnesses. However, a persistent—and dangerous—myth is that raw milk is a healthier alternative, despite no meaningful nutritional difference being found between the two.

Contamination from Raw Milk

Consumption of unpasteurized milk is a major cause of milk-related diseases due to the potential presence of dangerous pathogens. These can originate from the animal itself or from contamination during milking, storage, and handling.

Campylobacter: The most frequently identified pathogen in raw milk outbreaks, causing diarrhea, fever, and abdominal pain. Severe cases can lead to Guillain–Barré syndrome, a rare but serious autoimmune disorder.
E. coli (Shiga toxin-producing): Certain strains can cause severe intestinal disease, including bloody diarrhea, and in children, hemolytic uremic syndrome (HUS), which can lead to kidney failure.
Listeria monocytogenes: This bacterium can cause listeriosis, a serious infection that is particularly dangerous for pregnant women, newborns, and immunocompromised individuals. It can lead to miscarriage, stillbirth, and long-term neurological damage.
Salmonella: A common cause of food poisoning, leading to fever, vomiting, and diarrhea.
Brucella: Causes brucellosis, an infectious disease that can lead to long-term health problems.

Common Digestive Issues: Lactose Intolerance and Allergies

Beyond contamination risks, many people experience adverse reactions to milk due to its natural components. It is crucial to distinguish between a food allergy and a food intolerance, as their causes and severity differ significantly.

Milk Allergy

Cause: An immune system response to milk proteins (casein and whey), mistaking them for harmful invaders.
Symptoms: Can be rapid (minutes to an hour) and include hives, wheezing, swelling of the lips, tongue, or throat, vomiting, and in severe cases, life-threatening anaphylaxis.
Prevalence: Most common in infants and young children, though many outgrow it.

Lactose Intolerance

Cause: The inability to fully digest lactose, the sugar found in milk, due to a deficiency of the lactase enzyme.
Symptoms: Generally appear 30 minutes to two hours after consumption and are digestive in nature, such as bloating, abdominal pain, gas, and diarrhea.
Prevalence: Extremely common, affecting an estimated 68% of the global population and often developing with age.

Milk and Chronic Health Concerns

While the link between dairy and certain chronic diseases is more complex and debated, some studies suggest potential associations. The impact can vary depending on the type of dairy, individual genetics, and overall diet.

Dairy and Inflammatory Conditions

Some research suggests that dairy can act as a trigger for inflammatory responses in susceptible individuals. The hormones and certain milk proteins may disrupt insulin levels and contribute to inflammation.

Acne: Multiple studies have observed a correlation between higher milk, particularly skim and low-fat milk, consumption and an increased risk of acne in adolescents and young adults.
Eczema and Psoriasis: Dairy has also been identified as a potential trigger for inflammatory skin conditions like eczema and psoriasis.

Cancer and Other Diseases

The relationship between dairy consumption and cancer is inconsistent across studies, with research suggesting both potential risks and protective effects depending on the cancer type.

Prostate Cancer: Some studies have linked high dairy intake to an increased risk of prostate cancer, possibly due to hormones like IGF-1.
Colorectal Cancer: Conversely, dairy consumption is often associated with a decreased risk of colorectal cancer.
Heart Disease: While earlier concerns existed regarding the saturated fat in dairy, recent meta-analyses and trials have found no adverse effect of total dairy consumption on cardiovascular disease risk.
Type 2 Diabetes: Evidence is mixed, with some studies showing an inverse relationship (especially with fermented products like yogurt) and others finding no significant association.

Outbound Link: The Role of Processing

To better understand the differences in processing and its effects on safety, the CDC offers comprehensive resources. For a detailed comparison and information on pasteurization, visit their website to explore the specifics of raw milk vs. pasteurized milk.

Comparison: Raw Milk vs. Pasteurized Milk


Feature	Raw (Unpasteurized) Milk	Pasteurized Milk
Safety Risk	High risk due to harmful bacteria.	Low risk; heating kills pathogens.
Common Bacteria	Campylobacter, E. coli, Listeria, Salmonella.	Pathogens are eliminated by heating process.
Nutritional Content	No proven nutritional superiority.	No meaningful nutritional difference from raw.
Flavor/Taste	Often described as having a richer flavor.	Standardized flavor, less variable.
Regulatory Status	Heavily regulated or banned in many regions.	Standard and widely available.
Associated Outbreaks	Disproportionately high number of outbreaks.	Low incidence of foodborne illness.

Conclusion: Making an Informed Choice

When considering potential health risks, it is clear that milk's effects are not uniform and depend heavily on individual factors and processing. The most immediate and severe dangers are overwhelmingly associated with raw, unpasteurized milk due to bacterial contamination. For most people, pasteurized dairy is a safe and nutritious food. However, for those with lactose intolerance or milk protein allergies, avoiding milk is necessary to prevent adverse symptoms. The potential links between dairy and chronic diseases like acne or certain cancers are subjects of ongoing research and suggest that milk's impact can be complex and influenced by the specific type of dairy and individual biology. Consumers can make the most informed choice by understanding their own body's reactions and prioritizing pasteurized products to mitigate food safety risks.

Frequently Asked Questions

No, it is not recommended to drink raw milk. Unpasteurized milk can contain dangerous bacteria, including E. coli, Salmonella, and Listeria, which can cause severe illness, hospitalization, and even death.

Lactose intolerance is a digestive issue where the body cannot properly break down the sugar in milk (lactose), leading to gastrointestinal symptoms. A milk allergy, however, is an immune system reaction to milk proteins, which can cause hives, swelling, and, in severe cases, anaphylaxis.

Some observational studies have found a positive association between dairy consumption, particularly skim and low-fat milk, and the development of acne. This is thought to be related to hormones and other bioactive molecules in milk.

No, pasteurization does not significantly reduce milk's nutritional value. Studies have found no meaningful difference in the nutrient content of pasteurized and unpasteurized milk.

The evidence on dairy and cancer is conflicting. Some research suggests a higher intake of dairy may be associated with an increased risk of prostate cancer, while other studies link dairy to a decreased risk of colorectal cancer. Overall, the evidence is inconsistent.

Milk protein intolerance is a delayed, non-immune reaction to milk proteins, often causing digestive issues like bloating and diarrhea. It is different from an immediate milk allergy, which is an immune (IgE-mediated) response that can be severe.

The relationship between milk and inflammation is debated. Some studies suggest a potential link to increased inflammatory markers in certain individuals, while other reviews find no pro-inflammatory effect in healthy adults. The effect can depend on processing and individual factors.