Milk is healthy because it promotes healthy bodily functions and has an array of health benefits.

The argument

Research has shown varying health benefits to drinking milk, and the case for calling it healthy rests on the number of different systems those benefits reach rather than on any single one of them. The most commonly known is improved bone health. The high calcium content in milk helps build up strong and dense bone structure and teeth, protecting against bone loss, osteoporosis, described as weak or brittle bone disease, and bone breakage or fracture. What makes milk more than a calcium source, on this account, is that it also supplies the vitamin D that aids calcium absorption, so the two arrive together and the second makes the first usable. A mineral the body cannot take up does little for the skeleton. Milk can also have positive effects on brain health. It can increase antioxidant levels in the brain, making it healthier, and the vitamin D can contribute to serotonin production. Serotonin is a neurotransmitter in the brain that is associated with happiness, sleep regulation, and appetite, which is why a change in its level would be expected to show up across several apparently unrelated aspects of daily life at once. Some studies have shown milk to increase serotonin levels and alleviate symptoms of depression. The remaining benefits are attributed to other constituents. Muscle building and weight loss can be aided by milk consumption due to its high levels of protein: protein is critical to build muscle mass and heal wounds, and milk contains lots of protein, so the same food serves both the athlete and the recovering patient. The potassium in milk can also help reduce the risk of cardiovascular disease, improving heart and blood health. Taken together, proponents argue, these effects reach bone, brain, muscle and heart, which is why milk promotes healthy bodily functions and has an array of health benefits.

Premises

Counter-arguments

-Milk can actually cause weaker bones, because the acids it produces draw on calcium from the bones to neutralize them. -Many proclaimed health benefits of milk are the results of one or a few studies, and not confirmed to be true.

Rejecting the premises

[Rejecting P1] The bone claim is weaker than the premise allows. Calcium intake is necessary for bone formation, but large prospective cohort studies have not consistently found that higher milk consumption reduces fracture risk in adults, and countries with the highest dairy intake do not have the lowest hip-fracture rates. The vitamin D is also not intrinsic to milk in most markets — it is added by fortification, which is a public-health policy rather than a property of the food. [Rejecting P2] The brain and mood claims are the thinnest in the entry. The chain from dietary vitamin D through serotonin synthesis to relief of depressive symptoms is several inferential steps long, and the counter-argument on record makes the general point that many of the benefits listed rest on one or a few studies rather than on established findings. [Rejecting P3] Protein and potassium are supplied by a very wide range of foods, so their presence establishes that milk is nutritious rather than that it is healthy in the contested sense. Weight loss in particular does not follow from protein content, since milk also supplies energy. [Rejecting C] The conclusion is also drawn as though it applied to everyone, when the majority of the world's adult population has reduced lactase activity and does not digest lactose comfortably. (The counter's own case is weak on its central point — the acid-load account of bone loss it invokes is not well supported — and is a candidate for replacement.)