eileen

Rickets on the rise as breast-feeding and limiting sun exposure become more prevalent

Posted by Brie Zeltner April 15, 2008 03:02AM

Graphic: A child with rickets (pdf).
The disease often starts with pain in the legs, arms and spine. But babies with rickets can't tell anyone about the pain, so it's usually a seizure, a broken bone or the characteristic bowed legs that finally trigger a diagnosis. Rickets -- a childhood disease caused by vitamin D deficiency and usually associated with the sooty skies of the industrial age -- is making a comeback.
And the reasons are surprising.
Few would suspect that changing from infant formula to exclusively breast milk or our increasing vigilance against too much time in the sun would expose babies to a vitamin deficiency. But vitamin D is called the "sunshine vitamin" for good reason -- the easiest way your body gets what you need is from the sun's UV rays.
But our sun-shunning behavior the past few decades, fueled by fears of skin cancer and the sun's aging effects on skin, set us up for vitamin D deficiency across the population.
Mothers pass on vitamin D to their babies in the last few weeks of a full-term pregnancy. If Mom has a robust store of vitamin D, then baby should get enough to last a little while.
Infant formula is supplemented with vitamin D, so babies can make up for their low stores at birth.
But localpediatricians are referring an increasing number of newborns and infants, mostly those who were exclusively breast-fed, to endocrinologists because of rickets.
Premature babies, born before that vitamin D transfer happens, are at even higher risk for a deficiency.
The disease usually becomes apparent when a child starts to walk and puts pressure on the bones. Vitamin D helps the body absorb calcium from foods and deposit it into the bones to make them strong. The hallmark sign of rickets is bowed legs.
There are earlier signs, though, too.
Infants with vitamin D deficiencies who haven't started walking sometimes develop chest deformities and widened wrists and ankles. And many babies with a deficiency end up hospitalized after having a seizure because the level of calcium in their blood is so low.
Softened skull bones may be an issue as well, with a recent study in Japan finding that 22 percent of a sample of newborns had softened skull bones a week after birth, which means their mothers most likely were very vitamin D deficient during pregnancy.
Sometimes a toddler who isn't walking well is referred to a specialist, said Dr. Ajuah Davis, pediatric endocrinologist at MetroHealth Medical Center, who saw about 20 cases of rickets last year.
"It's a little skewed at Metro because we see so many African-American and Middle Eastern patients," Davis said. Darker-skinned people have a harder time making vitamin D from sunlight because melanin in their skin acts as a natural sunscreen. Cultural norms also play a role -- many of the women Davis sees who have babies with rickets wear body-covering clothing.
Vitamin D: The sunshine vitamin

Recommended: 200 to 600 IU a day, depending on age. More for older people because their skin has a harder time making vitamin D, and the kidneys have a harder time converting it into a usable form. The National Academy of Sciences set the upper limit for intake between 1,000 IU for infants and 2,000 IU for pregnant women.

At a National Institutes of Health conference last year, researchers discussed the growing prevalence of vitamin D insufficiency and deficiency in the population. Many think the result will be a recommendation to increase daily intake.

Sources: Oily fish -- salmon, mackerel, sardines and tuna -- and fortified milk and cereals are the best food sources.

Eggs have some in their yolks. Liver and shiitake mushrooms also are sources, albeit poor ones.

Supplementation and sunshine without sunscreen are the easiest ways to get the vitamin. D3, or cholecalciferol, is the best supplement. D2, or ergocalciferol, is in about half of multivitamin supplements and is harder for the body to convert to a usable form.
Most parents are surprised when they learn what the problem is, particularly when the child has been breast-fed, because it seems that everything a baby needs should be in breast milk, doctors say. That probably was the case when we all spent more time outside, working outdoors with more skin exposed to sunlight, said Dr. Cyndney Fenton, associate professor of pediatrics at Akron Children's Hospital. That's not the case now though, especially at this time of the year.
"I guarantee probably more than 50 to 60 percent of women in Northeast Ohio, if we measured them today, would be on the deficient side just because we're not getting enough sunlight," Fenton said.
So babies are getting a double whammy -- not enough vitamin D from sun-shunning Mom's low stores before birth and then a poor source of vitamin D in breast milk.
Add to this that babies usually are not exposed to any sun without protection and you have a recipe for, well, rickets.
Fortunately, the disease is very treatable. Rarely will a child need more than high doses of vitamin D to reverse the symptoms.
What worries doctors is that there are many people of all ages who may not fit the clinical definition for deficiency, but who have vitamin D levels low enough to prompt long-term problems.
A flood of studies in the past year have established links between low vitamin D levels and diseases such as colon and breast cancer, multiple sclerosis, rheumatoid arthritis and depression.
Michael Holick, director of the vitamin D research laboratory at Boston University, said the results are "not surprising, because there are vitamin D receptors in every tissue in the body." Holick has researched the vitamin since 1967.
Holick infuriated the dermatology community in 2004 when he published "The UV Advantage," a book advocating limited unprotected sun exposure in addition to vitamin D supplements as the best way to combat the widespread deficiency he'd seen in his studies.
Holick was accused of having financial backing from the tanning industry when he wrote the book, a charge he denies.
Despite losing his credentials in the Boston University Dermatology Department, he stands by his recommendation of 10 minutes of unprotected exposure on the arms and legs two or three times a week. He takes 1,400 IU (international units) of vitamin D per day, which is higher than the recommended 200 to 600 IU. While it is possible to take too much vitamin D, you would have to take more than 10,000 IU every day for months to cause a problem. The body destroys any excess vitamin D produced in the skin from sun exposure.
Holick says a good measure of the right sun exposure is about a quarter of the time it would take to make your skin pink. He thinks the reluctance to recommend any sun exposure is silly: "They think people are stupid, and if you tell them to get moderate sun exposure, they'll overdo it."
The key is moderation, both in taking and getting out in the sun.

SOURCE LINK: http://blog.cleveland.com/lifestyles...s_breastf.html
IMAGE CREDIT: WILLIAM NEFF | THE PLAIN DEALER

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"under exposure to UV rays is as dangerous as overexposure....this is D life" eileen