Not to be outdone by Johns Hopkins, Harvard Medical Group
also published a review in the New England Journal of Medicine about
milk and health.
They start out by “stating the obvious” that the natural
function of milk is to nourish and promote the growth of young mammals, not
mature ones. They go on to question the
current dietary recommendation of three 8-ounce servings of milk/milk product
per day.
Because cows are bred for high milk production and
because they are pregnant during most of the time they are milked, they produce
high levels of insulin-like growth factor (IGF-1) and high levels of estrogen
and other hormones.
Exposure to IGF-1 and other hormones has been linked to a
greater risk for certain cancers: breast, ovarian, uterus and prostate.
Cow milk intake has been correlated with the development
of diabetes, especially type 1 diabetes owing to cross reactivity between dairy
proteins and pancreatic islet cells.
A long-standing rationale for promoting lifelong milk
consumption is to meet calcium requirements for bone health. The concept is good but the practical outcome
is the opposite. Hundreds of scientific
studies show that countries with the greatest milk intake have the poorest bone
density. Yes, milk is rich in calcium,
but it also contains certain proteins that leach away the mineral content of
our bones. Countries with the lowest
milk intake paradoxically have the best bone health. Cow milk is also the most common cause for
food allergy, at least in Western countries.
Finally, there is the “fart” issue. As hard as it seems to believe, the methane
produced due to the large industrial scale of milk production is having a
measurable effect on green house gases.
The Harvard group calculated that obtaining our protein from alternative
sources such as soy, legumes, and grains rather than from milk would reduce
global greenhouse gases by 10 percent.