No, not all humans are allergic to milk. However, many people experience issues with milk digestion.
While a milk allergy and lactose intolerance are often confused, they are distinct conditions:
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Milk Allergy: A true milk allergy is an immune system response to one or more of the proteins in milk (usually casein or whey). This can cause symptoms ranging from mild hives to severe anaphylaxis.
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Lactose Intolerance: Lactose intolerance is caused by a deficiency of the enzyme lactase, which is needed to digest lactose, the sugar found in milk. Symptoms usually involve digestive discomfort such as bloating, gas, and diarrhea. The provided reference notes that approximately 65% of the global population has a reduced ability to digest lactose after infancy due to lactase nonpersistence.
Key Differences Between Milk Allergy and Lactose Intolerance
| Feature | Milk Allergy | Lactose Intolerance |
|---|---|---|
| Cause | Immune system reaction to milk protein(s) | Deficiency of the lactase enzyme |
| Symptoms | Hives, vomiting, anaphylaxis (severe reactions) | Bloating, gas, diarrhea (digestive discomfort) |
| Prevalence | Less common | More common (around 65% of the global population) |
| Severity | Potentially life-threatening | Generally not life-threatening |
Therefore, while a large portion of the population experiences lactose intolerance, a milk allergy is less common. It's also crucial to remember that lactose intolerance varies in severity from person to person.
