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Milk: Does It Really Do a Body Good?

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For all the dinner table differences across America, a glass of milk—and the requirement that it must be finished before leaving the table—seems to be a constant, at least it was when I was growing up. Though the “Got Milk?” campaign wasn’t yet released when I was a kid, it was widely believed that milk was integral in building strong bones and teeth. It was a parent’s liquid solution to good nutrition when kids wouldn’t touch the veggies. 


But although the bland white stuff seems as uncontroversial as apple pie, milk has its vehement detractors. Opponents of milk, including the Anti-Dairy Coalition and Notmilk.com, claim that cow’s milk should be for calves, not people. They point to dairy products as a source of many evils, including allergies, heart disease, and cancer.


The pro-dairy contingent, on the other hand, lauds dairy and milk for their calcium content and bone-building benefits.


So, who’s correct? It can be hard to wade through the cow pies to reason what’s right, and the evidence is far from clear.  


Milkin’ It
There’s no doubt that dairy products, and milk in particular, are packed with good stuff. It’s high in protein and calcium, and most milk products are supplemented with Vitamin D and A. But although the United States Department of Agriculture (who has the conflicting role of both regulating and promoting dairy) recommends three servings of milk a day, this may be too much. Although most of us immediately equate milk with strong bones, dairy products have perhaps been oversold in this arena.


While it’s well known that our bones need calcium, some studies suggest that high calcium intake doesn’t necessarily lower a person’s risk for osteoporosis or fractures. A Harvard study found that people who drank two or more glasses of milk had no greater protection from breaking a bone than those who drank a glass or less a week. A 2007 study published in the American Journal of Nutrition pooled multiple studies and found that “results from prospective cohort studies suggest that calcium intake is not significantly associated with hip fracture risk in women or men.”


Then there’s the associational evidence from other countries where dairy and/or milk consumption is low. Places like India, China, and Japan have lower levels of dairy calcium intake, but the incidence of bone fractures and osteoporosis is also quite low. Of course, other factors important in increasing bone strength, such as physical activity level and vitamin D, may contribute to this lowered risk. Still, an international study published in 2005 concluded, “no significant relationship was observed by age for low milk intake and hip fracture risk.”


Mooin’ No Harm?
Although there’s no doubt that we need calcium, as well as other nutrients, for bone building, the exact amount has yet to be determined. But so, too, do the claims of milk’s bad aspects. Some anti-dairy advocates claim that dairy can lead to heart disease. Much of this claim is based on high saturated fat and high cholesterol dairy products, like cheeses and creams, which may indeed contribute to cardiovascular problems. But lowfat and nonfat options are also available, and in small amounts eaten infrequently, high fat products aren’t likely to be a major concern.


Then there’s the claim that dairy can contribute to cancer. Some studies have linked high milk intakes with a risk of prostate cancer; this seems to be caused by high-fat dairy products, not dairy in general.


Conversely, a 2006 study published in the British Journal of Nutrition reviewed all the evidence of the health effects of dairy and found many positives. The study concluded that dairy products are associated with a reduced risk of hypertension, stroke, and colon cancer, but also noted there is weak evidence showing the protective benefit of dairy on bone health.


Greener Pastures
Perhaps one of the real problems with milk is that many people are lactose intolerant. Somewhere between 50 to 90 percent of Mexican, African, and Asian Americans lack or have low levels of the enzyme lactase, which is needed to digest milk. Luckily for these people, and those that simply don’t like milk, there are many alternatives. Soy, rice, and almond milk are widely available. For those that worry about the environmental impacts of dairy production, organic milk and milk without rBGH (recombinant bovine growth hormone) is also becoming more and more common.


And although milk was always touted as the only thing we need for our bones, one of the most important, yet least promoted, factors involved in strengthening bones and reducing risk of osteoporosis is weight-bearing exercise, such as jogging, walking, and weight lifting. This, of course, doesn’t fit so succinctly into the ad campaign.


Plus, dairy products don’t hold the market on calcium; green leafy vegetables, like spinach and kale, as well as anchovies, salmon, and legumes are other great sources of the mineral. It’s just harder to get kids to eat those.


Holy Cow
Perhaps we should think of dairy as less like a nutrient and more like a food. If you like it, eat it. If not, find alternatives. Because although some claims made by the dairy industry may not be completely true, when I eat a slice of Camembert or a dollop of freshly whipped cream, I’m not thinking about calcium, protein, or any such thing. I’m thinking delicious.


Photo courtesy of LFL16 on flickr (cc)

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