Milk is unhealthy because people are intolerant or allergic to it.

The argument

A significant number of people worldwide experience adverse health effects when consuming milk or dairy products, which on this argument counts against treating it as a healthy food. The most common of these effects is a matter of ordinary human variation rather than of illness. Lactose, a sugar in milk, requires the enzyme lactase in the human body to break it down. When people do not produce enough lactase, they can have lactose intolerance and have trouble digesting milk. This can lead to bloating, diarrhea, and other digestive problems when consuming milk. Because a significant number of people worldwide do not produce enough of the enzyme, the difficulty is not a rare defect but a widespread condition, and a food that so many people cannot digest is a poor candidate for a dietary staple. Some people also have a milk allergy, which works by a different mechanism and carries a different level of risk. This is when the body recognizes casein, the protein in milk, as a threat, so it produces an immunological response to this threat, giving symptoms of allergies. This can lead to vomiting, hives, and even fatal anaphylactic shock. An allergic reaction is not a matter of discomfort in the way intolerance is; the response is to the protein itself, and at its extreme it is life-threatening. The proteins are implicated in a milder complaint as well. Casein and whey, another protein in milk, also produce hormones known to cause acne when humans digest them, and can aggravate or cause acne problems — an effect that follows from digesting milk in the ordinary way rather than from any intolerance or allergy. Taken together, the argument holds, milk produces digestive trouble in those who cannot break down its sugar, dangerous immune reactions in those whose bodies treat its protein as a threat, and hormonal effects in those who process it without incident. Because so many people are intolerant or allergic to it, milk is unhealthy.

Premises

Counter-arguments

-Not everybody is lactose intolerant or allergic to milk. -Lactose-free milks are available.

Rejecting the premises

[Rejecting P1] That some people cannot digest lactose shows milk is unsuitable for them, not that it is unhealthy in itself. An intolerance is a property of the person as much as of the food. [Rejecting P2] Allergy works the same way, and it applies to many ordinary foods — peanuts, shellfish, eggs — none of which is called unhealthy on that ground. [Rejecting P3] The hormone-and-acne claim is offered without a source and concerns an effect in some people rather than the general health question the position asks about. As the counter-argument notes, lactose-free products exist for those who cannot digest it, which the premise does not address.