A little sun may ward off cancer
Posted: Sat May 27, 2006 8:09 am
Experts say vitamin D has loads of health benefits but warn not to ditch the sunblock
By LAURA BEIL / The Dallas Morning News
Just in time for summer, medical researchers are warming to the idea of sunlight.
While it's still the same cancer-causing, skin-shriveling hazard it always was, the sun also primes the skin to make vitamin D, which – if a flurry of recent evidence stands – may help protect against many major ailments: colon, breast and prostate cancer; diabetes; high blood pressure; tuberculosis; arthritis and more.
Even cancer specialists who have championed sun restraint for a generation are seeing a new light.
"I've gone from being a skeptic to, if not a believer, someone who would say there is something there," said Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society. This week, his organization, along with the Canadian Cancer Society and other groups, issued new advice about obtaining vitamin D.
But don't ditch the Coppertone. No one advises wallowing in the sun. If you're fair-skinned and sitting outside to read this story, you will probably make the vitamin D you need by the time you reach last sentence, with the sunlight absorbed by the hands and face.
In fact, many dermatologists, who spend their days trying to repair sun-baked skin, fear that unchecked enthusiasm for vitamin D threatens years of work in cancer prevention. Even if vitamin D does live up to its billing, seeking out the sun and giving up sunblock is unhealthy and unnecessary, says Dr. Stephen Stone, president of the American Academy of Dermatology. A person can make sufficient vitamin D just going about life, he says.
Vitamin D also comes in supplements, and is found in milk, some fatty fish like salmon and sardines, cod liver oil and fortified orange juice.
The concern, Dr. Stone said, is that the new research on vitamin D will be "used as a justification for tanning and tanning salons." This worry has even led to stark disagreements within scientific circles.
"I was fired," said Dr. Michael Holick, a vitamin D expert who was on the dermatology faculty of Boston University. That is, until he penned a book titled, The UV Advantage. He remains at BU in another appointment.
Even Dr. Holick advises only about five to 10 minutes of sun on the extremities, two to three times a week, to get enough vitamin D, though specifics depend on location, time, and skin tone. (Some of Dr. Holick's critics point out that he gets funding from the tanning industry, and he does. His reply is that the money flows directly to the university and represents a small fraction of his budget.)
Programmed by nature
Scientists have long noted intriguing observations that raise the possibility of a role for vitamin D in cancer prevention. Common cancers strike more frequently among those in higher latitudes. African-Americans – whose skin pigment hinders vitamin D production – also show an increased risk of malignancies.
Recent studies have gone beyond cancer protection. For example, in March, Boston researchers described a study of more than 80,000 women, of whom 4,800 developed diabetes over 20 years. Those with the highest intakes of calcium and vitamin D had the lowest risk of diabetes.
"Nature wanted us to make vitamin D upon exposure to the sun," said Dr. Anastassios Pittas of Tufts-New England Medical Center, the study's lead author.
Whether from the diet or the sun, the vitamin goes through a two-step conversion that leaves it in the workhorse form called "hormonal vitamin D." The hormonal vitamin D primarily aids in the absorption and regulation of calcium, but may also affect cell growth and death – thus the cancer links – the strength of bones or the integrity of the immune system.
Cancer protection
While this could affect many conditions, some of the most tantalizing evidence lies in cancer protection. In April, during a meeting of the American Association for Cancer Research, researchers from the University of California, San Diego, reported that breast cancer risk and vitamin D blood levels went hand-in-hand: the higher the vitamin D, the lower the risk of breast cancer. Another study found the risk particularly pronounced for vitamin D obtained early in life during breast development. Scientists have reported the same relationship for colon cancer, and the association is stronger.
Similar findings for overall cancer incidence and mortality appeared in April in the Journal of the National Cancer Institute. At least one study is under way testing a vitamin D-derived drug for prostate cancer treatment.
Not every report has been positive. Headlines earlier this year reported that supplemental calcium and vitamin D didn't seem to help women prevent fractures. (Those data have been criticized, however, for not taking into account the fact that many women in the study didn't comply with the treatment or take adequate amounts.)
Still, aside from what's known about the basic biology, most human evidence in support of vitamin D is based the kinds of studies that make cause and effect difficult to determine. And researchers aren't forgetting the ideas that looked good in early sailing but sank upon rigorous experimental tests: beta-carotene for cancer, vitamin E for cancer and cardiovascular health, hormone replacement therapy for heart disease.
Nonetheless, the vitamin D experts say, many Americans could probably stand to get more of the hormone. Some studies have suggested that more than half of all black Americans do not have healthy levels of vitamin D. Americans who live in the North, endure long winters or are elderly also have a harder time making vitamin D.
Just 15 minutes
The American Cancer Society won't recommend an amount for sun exposure to boost vitamin D, except to say that the time doesn't have to be long. Broad advice would be difficult in a country where people live across different climates, are of different ages and different races.
And getting the nutrient from diet alone, given the limited number of vitamin D-rich foods, might not approach what some experts say is necessary to see the most benefit. The official recommendation now is now between 200 to 600 international units per day (depending on age), but research supports a number that is at least 1,000 or more.
Some vitamin D experts believe the government should explore wider food supplementation and higher intake recommendations, given the mounting indications of its disease prevention properties. What's needed most, scientists say, are experimental trials that could definitively test the theories and offer deeper understanding, and determine exactly how much vitamin D a person needs to reap any benefit.
Meanwhile, doctors say, people should neither loathe nor love the sun. "Go outdoors, and 15 minutes later put on your sunscreen," said Dr. Robert Heaney of Creighton University in Nebraska, one of the country's foremost authorities on Vitamin D. "You're not going to get seriously sunburned in 15 minutes."
http://www.dallasnews.com/sharedcontent ... 0e4ee.html
By LAURA BEIL / The Dallas Morning News
Just in time for summer, medical researchers are warming to the idea of sunlight.
While it's still the same cancer-causing, skin-shriveling hazard it always was, the sun also primes the skin to make vitamin D, which – if a flurry of recent evidence stands – may help protect against many major ailments: colon, breast and prostate cancer; diabetes; high blood pressure; tuberculosis; arthritis and more.
Even cancer specialists who have championed sun restraint for a generation are seeing a new light.
"I've gone from being a skeptic to, if not a believer, someone who would say there is something there," said Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society. This week, his organization, along with the Canadian Cancer Society and other groups, issued new advice about obtaining vitamin D.
But don't ditch the Coppertone. No one advises wallowing in the sun. If you're fair-skinned and sitting outside to read this story, you will probably make the vitamin D you need by the time you reach last sentence, with the sunlight absorbed by the hands and face.
In fact, many dermatologists, who spend their days trying to repair sun-baked skin, fear that unchecked enthusiasm for vitamin D threatens years of work in cancer prevention. Even if vitamin D does live up to its billing, seeking out the sun and giving up sunblock is unhealthy and unnecessary, says Dr. Stephen Stone, president of the American Academy of Dermatology. A person can make sufficient vitamin D just going about life, he says.
Vitamin D also comes in supplements, and is found in milk, some fatty fish like salmon and sardines, cod liver oil and fortified orange juice.
The concern, Dr. Stone said, is that the new research on vitamin D will be "used as a justification for tanning and tanning salons." This worry has even led to stark disagreements within scientific circles.
"I was fired," said Dr. Michael Holick, a vitamin D expert who was on the dermatology faculty of Boston University. That is, until he penned a book titled, The UV Advantage. He remains at BU in another appointment.
Even Dr. Holick advises only about five to 10 minutes of sun on the extremities, two to three times a week, to get enough vitamin D, though specifics depend on location, time, and skin tone. (Some of Dr. Holick's critics point out that he gets funding from the tanning industry, and he does. His reply is that the money flows directly to the university and represents a small fraction of his budget.)
Programmed by nature
Scientists have long noted intriguing observations that raise the possibility of a role for vitamin D in cancer prevention. Common cancers strike more frequently among those in higher latitudes. African-Americans – whose skin pigment hinders vitamin D production – also show an increased risk of malignancies.
Recent studies have gone beyond cancer protection. For example, in March, Boston researchers described a study of more than 80,000 women, of whom 4,800 developed diabetes over 20 years. Those with the highest intakes of calcium and vitamin D had the lowest risk of diabetes.
"Nature wanted us to make vitamin D upon exposure to the sun," said Dr. Anastassios Pittas of Tufts-New England Medical Center, the study's lead author.
Whether from the diet or the sun, the vitamin goes through a two-step conversion that leaves it in the workhorse form called "hormonal vitamin D." The hormonal vitamin D primarily aids in the absorption and regulation of calcium, but may also affect cell growth and death – thus the cancer links – the strength of bones or the integrity of the immune system.
Cancer protection
While this could affect many conditions, some of the most tantalizing evidence lies in cancer protection. In April, during a meeting of the American Association for Cancer Research, researchers from the University of California, San Diego, reported that breast cancer risk and vitamin D blood levels went hand-in-hand: the higher the vitamin D, the lower the risk of breast cancer. Another study found the risk particularly pronounced for vitamin D obtained early in life during breast development. Scientists have reported the same relationship for colon cancer, and the association is stronger.
Similar findings for overall cancer incidence and mortality appeared in April in the Journal of the National Cancer Institute. At least one study is under way testing a vitamin D-derived drug for prostate cancer treatment.
Not every report has been positive. Headlines earlier this year reported that supplemental calcium and vitamin D didn't seem to help women prevent fractures. (Those data have been criticized, however, for not taking into account the fact that many women in the study didn't comply with the treatment or take adequate amounts.)
Still, aside from what's known about the basic biology, most human evidence in support of vitamin D is based the kinds of studies that make cause and effect difficult to determine. And researchers aren't forgetting the ideas that looked good in early sailing but sank upon rigorous experimental tests: beta-carotene for cancer, vitamin E for cancer and cardiovascular health, hormone replacement therapy for heart disease.
Nonetheless, the vitamin D experts say, many Americans could probably stand to get more of the hormone. Some studies have suggested that more than half of all black Americans do not have healthy levels of vitamin D. Americans who live in the North, endure long winters or are elderly also have a harder time making vitamin D.
Just 15 minutes
The American Cancer Society won't recommend an amount for sun exposure to boost vitamin D, except to say that the time doesn't have to be long. Broad advice would be difficult in a country where people live across different climates, are of different ages and different races.
And getting the nutrient from diet alone, given the limited number of vitamin D-rich foods, might not approach what some experts say is necessary to see the most benefit. The official recommendation now is now between 200 to 600 international units per day (depending on age), but research supports a number that is at least 1,000 or more.
Some vitamin D experts believe the government should explore wider food supplementation and higher intake recommendations, given the mounting indications of its disease prevention properties. What's needed most, scientists say, are experimental trials that could definitively test the theories and offer deeper understanding, and determine exactly how much vitamin D a person needs to reap any benefit.
Meanwhile, doctors say, people should neither loathe nor love the sun. "Go outdoors, and 15 minutes later put on your sunscreen," said Dr. Robert Heaney of Creighton University in Nebraska, one of the country's foremost authorities on Vitamin D. "You're not going to get seriously sunburned in 15 minutes."
http://www.dallasnews.com/sharedcontent ... 0e4ee.html