Skin wars

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http://www.medicalpost.com/mpcontent/article.jsp?content=20040719_192644_5084

 

July 28, 2004 Volume 40 Issue 28

 

Skin wars

 

Dermatologists warn about cancer while nutrition

experts bemoan vitamin D deficiencies. Who's right in

the battle under the sun?

 

By Celia Milne

 

TORONTO – This is the summer of the skin wars and one

of the first casualties is an American doctor who came

down on the wrong side of the debate.

 

Dr. Michael Holick, professor of medicine, physiology

and biophysics at Boston University Medical Centre

said in a recent interview with the Medical Post:

" Between 50,000 and 150,000 people die of cancers we

believe are because of vitamin D deficiency compared

with 7,000 a year due to melanoma and 1,200 due to

squamous and basal cell carcinoma. "

 

In his new book, The UV Advantage, he takes swipes at

the dermatology profession and sunscreen makers. " The

sophisticated and aggressive 'educational' campaigns

funded by the cosme-ceutical industry have created an

anti-sunshine hysteria that is detrimental to our

health because it converts people into sun-phobes by

convincing them that no amount of sun exposure is

safe, " he wrote. " The scare tactics have been embraced

by most of the dermatology profession. "

 

As a result of such comments, Dr. Holick is no longer

welcome by the dermatology department at Boston

University. (Until Feb. 2004, he was a professor of

dermatology there, but was asked to step down soon

after he completed his book. He has kept his other

appointments at the university.)

 

Any unprotected exposure to sun is bad, say American

dermatologists. Next, dermatologists will ban bikinis,

counters the tanning industry. Humans need direct

sunlight, say promoters of a new book on vitamin D.

The public isn't using enough sunscreen, says the Sun

Safety Alliance (founded by Coppertone).

 

As one cynical nutrition expert said about

dermatologists, they're only worried about their

" organ of interest. "

 

As dermatologists see it, exposure to the sun is a

cause of skin cancer. Yet vitamin D experts say that

although the sun may cause skin cancer, it also helps

protect against rickets, osteoporosis, osteomalacia,

type 1 diabetes, multiple sclerosis, rheumatoid

arthritis, hypertension, heart disease, breast cancer,

colon cancer, rectal cancer and prostate cancer.

 

" It's a teeter-totter, " said Dr. Reinhold Vieth (PhD)

from laboratory medicine and pathobiology in the

faculty of medicine at the University of Toronto. " On

one side of the teeter-totter you have the evidence

for skin cancer. That's what is holding everything

down. On the other side you have breast cancer,

prostate cancer, MS, diabetes all sitting there at the

top. We've come down too strongly on the melanoma

piece at one end of that balance. "

 

While changing popular wisdom isn't easy, several

messages do emerge clearly: Many Canadians are vitamin

D deficient; patients, especially the elderly, should

be tested for vitamin D deficiency using serum 25 (OH)

D; recommended daily requirements for vitamin D are

probably too low; the sun may be an important source

of vitamin D because ample amounts are difficult to

get through supplements; and more research is needed.

 

Trying hardest to change the balance of the

teeter-totter is the thick-skinned and

now-almost-infamous Dr. Holick. While he finds the

decision to fire him " incomprehensible, " he is an

optimist. " It has been wonderful, " he said, laughing.

" I am thrilled with the publicity. It has taken

vitamin D deficiency to a whole new level. I've been

recommending this for more than 20 years and no one

paid attention. "

 

What Dr. Holick is recommending does not seem

heretical: For optimal health people need between 800

and 1,500 IU of vitamin D a day. His book contains

charts showing how people of different skin types can

acquire this from the sun. A fair-skinned person

wearing a bathing suit on a beach near, say, New York,

should spend one or two minutes in the sun before

putting on sunscreen.

 

This kind of advice clearly gets under the skin of the

American Academy of Dermatology, which has said " any

group, organization or individual that disseminates

information encouraging exposure to UV radiation,

whether natural or artificial, is doing a disservice

to the public. "

 

The medical literature is now teeming with articles

showing various diseases—breast cancer, colon cancer,

osteoporosis, ovarian cancer, MS—are more common in

parts of the world that get less sun.

 

The first large prospective examination of whether MS

might be caused in part by a lack of sunlight was

published in the January 2004 issue of Neurology. In

the northern half of the United States, the incidence

of MS is far higher than in the Southern U.S. And in

areas near the equator, the rate of MS is very low.

 

The Harvard study, which involved almost 200,000 women

from the Nurses' Health Study, found that women who

took a vitamin D supplement (400 IU) cut their risk of

developing MS by 40%, compared with those who did not

take a supplement.

 

" I am pretty convinced by the Harvard study, " said Dr.

Hillel Panitch, a neurologist specializing in MS who

works at the University of Vermont in Burlington.

" That was a statistically significant outcome in a

huge number of people. " Still, he doesn't think people

should rush out into the sun half-naked as a result.

" There is no need for people to go and sunbathe and

increase their risk of skin cancer when a supplement

will do the same thing. "

 

Dr. David McLean, a dermatologist and head of cancer

prevention at the B.C. Cancer Agency, feels the same

way after his recent review of vitamin D literature.

" We definitely need vitamin D. The question is how

much, and how do we get it? " But he chooses his words

carefully when making recommendations about exposure

to the sun: " If you're out in the sun for more than 15

minutes, definitely use sunscreen. Walking to and from

the car, you don't need it. "

 

He concluded Canadians are generally getting enough

from various sources—oily fish such as salmon, casual

sun exposure in their daily lives and

multivitamins—and feels people are getting more

vitamin D through their skin than they think, even

when they are wearing sunscreen. " All liquid sunscreen

lets through ultraviolet light, even those with an SPF

of 60. Also, the average application is one-third the

amount used in testing, so 30 is actually 10. "

 

Dr. McLean feels that while Dr. Holick's vast body of

work is very impressive— " He has done good research. He

is not the enemy " — it is not necessary to dramatically

change the way we live.

 

" Is anything wrong? Yes, but it isn't a crisis. Better

to do what you normally do, " he said. And he agrees

with Dr. Panitch that supplements are the way to go.

" One in eight people gets skin cancer. There's huge

damage being done and if there are alternatives, why

not get a dose you know? "

 

But some Canadian doctors disagree strenuously.

Canadians need much more vitamin D than they are

getting, argues Dr. David Hanley, medical director of

the Grace Osteoporosis Centre and professor and head

of the division of endrocrinology and metabolism in

the department of medicine at the University of

Calgary.

 

In a study of the epidemiology of osteoporosis in

Canada (published in the Canadian Medical Association

Journal June 12, 2002) he found about one-third of

Calgarians are vitamin D deficient. This leads to

increased bone turnover and bone loss. " If we're

vitamin D deficient here, it likely applies everywhere

in the country. " He's an advocate of Dr. Holick's

proposal: " Caucasian adults should get sun on the back

and legs for 15 minutes in the summer. If they got

that every day they'd generate enough to last all

winter.

 

" Personally, I think the skin cancer risk is

over-rated, " he said. " Holick losing his job is the

most extreme form of this. "

 

In Canada, daily recommended intake values for vitamin

D are:

 

• 200 IU/day (5 mcg/day) for children and adults up to

age 50;

 

• 400 IU/day (10 mcg/day) for adults ages 50 to 70

years;

 

• 600 IU/day (15 mcg/day) for adults over the age of

70.

 

These were made back in the 1930s and 40s when

scientific information on vitamin D was scarce, said

Dr. Hanley. " Current evidence would suggest that's way

too low. "

 

Dr. Vieth agrees these RDIs are way too low. " To say

that adults need to take 200 IU—enough to prevent

rickets in a newborn baby—is absurd. " He is outraged

that dermatologists say there is no such thing as a

safe tan and they're advocating what amounts to a

" placebo " dose of vitamin D. " I would be quiet if

dermatologists started advocating vitamin D in the

amounts that sun-exposed skin would make, but they

have no idea beyond their organ of interest, so they

lose credibility. They need to double or triple the

amounts stated. "

 

Because the RDIs are set so low, said Dr. Vieth, it is

difficult or even impossible for people to easily

obtain supplements with enough vitamin D. " Eight

hundred to 1,000 IU will prevent osteoporosis. Few, if

any, products on the shelf have that level. "

 

The sun is a safer way to get the vitamin D we need

without getting too much, says Dr. William Grant

(PhD), a NASA scientists who studies sunlight,

nutrition and health. Taking too much through

supplements could draw calcium from the bones and

possibly increase risk for prostate cancer. With the

sun, on the other hand, " UVA can destroy some of the

excess vitamin D, and the tan developed by both UVB

and UVA helps protect the skin from too much

penetration of UV and production of free radicals. "

 

There is no hope of the RDIs going up soon, since the

joint U.S.-Canada Food and Nutrition Board won't start

their next review of nutrition until 2005 and any

changes would take several more years to institute.

Dr. Vieth said, " It might go up in 2007. It'll take

that long.

 

" Go out in the sun. Lie for 10 minutes on each side.

Enjoy yourself, " he said.

 

Health Canada is currently revising the " It's Your

Health " information sheet on vitamin D and tanning.

 

Dr. Vieth would like to study whether vitamin D

supplements prevent osteoporosis but his grant

applications to the Canadian Institutes for Health

Research have been rejected. Vitamins aren't a big

enough money-maker to be attractive to private

interests who fund research, said Drs. Vieth and

Hanley.

 

There is also a medical/legal issue surrounding large

doses of vitamin D since the government decided

" arbitrarily " in 1968 that 2,000 IU/day is the

tolerable upper intake level.

 

" Vitamin D doesn't often get into the mainstream

media. Probably because people don't make a lot of

money selling vitamin D, " said Dr. Hanley. Sunscreen

sales, on the other hand, are well over $500 million a

year in the U.S. alone, according to Forbes.com.

 

Two groups would particularly benefit most from a

clear message: children and the elderly.

 

A pro-sun message interpreted loosely by parents could

be very damaging said Dr. McLean: " I hope any

controversy doesn't take us back to where we were in

the 1930s and 40s when children were forced out into

the sunlight in the middle of the day. "

 

" The medical profession has to be careful in the

elderly. Some elderly who have had skin cancer are

over the deep end. They are terrified of the sun. They

literally leap from shade to shade. Frankly it's too

late. They've made cancer in childhood. "

 

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