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8 May 07
Got milk? If you do, you probably have acne vulgaris,
too!
Dr. F. W. Danby, a dermatologist in
private practice has had an interest in the interplay
between acne, hormones, dairy products and dietary
influences on skin disease that goes back over 30 years. As
an Assistant Professor of Medicine (Dermatology), he teaches
at Dartmouth Medical School.
Danby, who also runs a private practice in Manchester, New
Hampshire, believes that milk does indeed cause acne - and
that he knows what the mechanism could be.
Acne can affect anyone at any age, but it usually peaks at
between 16 and 18, when up to 98 per cent of the population
of Western countries is affected. A link between diet and
acne has been suggested because acne is less common in other
countries but increases when a Western diet is adopted. As
well as being socially excruciating, acne is costly - £2bn
is spent each year treating it.
Danby, who has long held that there is a link between diet
and acne, persuaded Dr Walter Willett and his colleagues at
the Harvard School of Public Health in Boston to look into
the matter.
Initially, Willet led in 2005 a group that wrote an article
widely published that promoted the idea that the link
existed. Then, he and Danby assembled a team of
researchers and delved further into the subject. The
link had been written about in medical literature since at
least 1931 according to Dr. Jerome Fisher's, M.D., Med. Sc.
D., Original 1965 Paper ACNE VULGARIS, A Study of One
Thousand Cases but until the team was formed there was not
much more than anecdotal support.
However, the team studied more than 47,000 women who are
part of a research project called the Nurses Health Study II
and the results are astounding.
The women were asked to complete questionnaires relating to
their diet as teenagers and to say whether they had ever
been diagnosed with severe acne. The study found no link
between food such as chocolate and chips and acne, but found
one between women who had acne and those who had drunk a lot
of milk.
 But
why should milk, such an essential bone-building nutrient,
be bad for our skin? Willett believes it's because of the
hormones in the milk, and Danby has taken this argument a
step further. What most dermatologists usually agree on is
that the male hormone testosterone (also found in women),
changes to dihydrotestosterone (DHT) in the sebaceous
glands, the oil-producing glands in the skin. Acne is
produced when the hormone causes too many of the cells that
line the duct of the gland to be produced too quickly.
Unable to separate from each other, they stick together and
form a plug in the pore - the first visible sign of acne.
Of course, everyone will respond differently to hormones. As
Danby says: "The ability to develop acne is partly genetic
and partly the result of hormone exposure. I tell my female
patients that genetics are the key to the fact that Paris
Hilton has lots of money and no zits and my patients have
lots of zits and no money. It is all genetics."
The milk most of us drink is produced by cows for their
calves. To ensure maximum milk yields cows are inseminated
days after giving birth to their calves, which are taken
away. A dairy cow will spend most of its life being milked
and being pregnant at the same time.
So milk is full of hormones: not only ones intended to help
the calf grow, but also those produced by the placenta to
aid the cow's pregnancy. They include DHT, and other
hormones that are the pre-cursors to DHT. In other words,
the hormones teenagers naturally produce are plentiful in
milk. It of course contains other growth-enhancing hormones
too - as Danby says: "Milk is, after all, specifically
designed to make things grow."
Another worrying hormone, as far as acne is concerned, is
IGF-1. This "grow th
factor" peaks at age 15 in girls and 18 in boys, coinciding
with peak acne levels. IGF-1 is thought to works with
testosterone and DHT to cause acne. IGF-1 is present in
cows' milk anyway, but levels rise by 10 per cent when cows
are given injections of recombinant bovine growth hormone
(rBGH) to increase milk yield. Drinking organic milk is not
a solution because the cows are still pregnant while
lactating, so they have the same hormones in their milk as
non-organic cows.
Danby's solution is to eliminate dairy from the diet - after
all, he says, the Perricone diet is practically dairy-free.
Nicholas Perricone, an American dermatologist who has
launched a range of skin products, has also developed a
skin-food diet based on eating large amounts of wild salmon.
However, Perricone's London-based nutritionist, Christopher
Lee, disagrees with Danby: "A diet high in sugars and
saturated fats is rich in free-radical-causing agents, which
will exacerbate acne. But acne is triggered by hormones and
is not caused by diet."
Saturated fats may play a role, but the Harvard Nurses study
found that acne was most closely linked to skimmed milk. The
researchers hypothesize that it is not the fat that is the
problem, but the hormones, which may be altered. For
instance, to give skimmed milk a creamier texture, whey is
often added, and the protein in whey can make other hormones
more reactive.
The Dairy Council isn't convinced, saying the study is
flawed because, first, it asked participants to remember
what they ate a decade ago and, second, it shows a link
between milk and acne, which is not the same as proving that
milk causes acne.
 Dr
Judith Bryans, the director of the Dairy Council, says:
"Science does not support links between acne and dairy
foods," and argues that, "unnecessary exclusion of dairy
from the diet can compromise nutrient intakes. This is
especially important for teenagers who are most likely to
suffer with acne, and for whom the bone-building nutrients
found naturally in dairy foods are so important."
To address this, another long-term study is about to be
published, looking at the Harvard Nurses' teenage children,
who should have no problem remembering what they're eating
and how many spots they have.
Danby agrees with the Dairy Council that the link between
acne and milk is unproven: "My dermatological colleagues
insist, with justification, on a full double-blind
randomized controlled trial. But so far it has been
impossible to arrange such a trial. Double-blinding dairy
intake is essentially impossible because we have no
hormone-free dairy we could feed people as a 'placebo'."
However, in defense of his dairy-free stance, he adds:
"Objectively, human consumption of large volumes of another
species' milk, especially when that milk comes mainly from
pregnant cows during the human's normally post-weaned years,
is essentially unnatural."
You can read more about this subject at
www.acnemilk.com, Dr. Danby's website.
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