Dear Dr. Bone,
Is it true that there is a difference in the
risk for cancer if you drink whole milk instead of skim or 2%? My friends and I
were discussing it at lunch. I thought the benefits of lower fat were all
related to heart disease, but they say that whole milk also contributes to
cancer. Who is right?
D.L.
Dear
D.L.
The
relationship between milk and cancer is complex. Countries whose inhabitants do
not consume much milk seem to have lower incidences of certain cancers. For
example, in Japan and Mongolia there is less breast cancer than in the United
States. One of the reasons posited for this phenomenon is the presence of
hormones in milk. In order for cows to produce more milk they are kept pregnant
for prolonged periods of time. Milk from pregnant cows naturally has a higher
estrogen content. Farmers also inject the cows with hormones. One in
particular, recombinant Bovine Growth Hormone (rBGH), results in milk that
contains higher amounts of Insulin-like Growth Factor, known as IGF-1. IGF-1
can be absorbed from the milk and stimulate cancer cells. Since hormones in
milk are fat soluble, it would seem safer to drink low fat milk. On the other
hand, conjugated linoleic acid, a natural anti-cancer molecule, is found at its
highest concentration in whole milk as is calcium, a necessary building block
for our bones.
The
popular book called The China Study looks into the relationship between diet
and cancer. I have many friends who became vegan after reading it because they
were convinced that dairy consumption can be dangerous, not just for cancer,
but for heart disease and other ailments too. A moderate by nature, I suggest
that each person find their comfort level after assessing the data. It is
unlikely that an occasional glass of milk or ice cream will cause cancer, but
dietary modifications along with exercise, decreasing alcohol consumption, and
controlling stress, should results in a longer, healthier life.
~ Dr. Bone
