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You Need Vitamin D to Live. How Could This Woman Survive With None in Her Blood? | You Need Vitamin D to Live. How Could This Woman Survive With None in Her Blood? |
(3 days later) | |
In 1992, a 33-year-old Lebanese woman had just immigrated to Canada and went to see a doctor. She was hunched over, and had limited mobility in her lower back, neck, shoulders and hips. Her doctor, Raymond Lewkonia at the University of Calgary, diagnosed her with ankylosing spondylitis, a medical condition that causes vertebrae in her spine to fuse, and thought that was it. | In 1992, a 33-year-old Lebanese woman had just immigrated to Canada and went to see a doctor. She was hunched over, and had limited mobility in her lower back, neck, shoulders and hips. Her doctor, Raymond Lewkonia at the University of Calgary, diagnosed her with ankylosing spondylitis, a medical condition that causes vertebrae in her spine to fuse, and thought that was it. |
Then, about eight years later, the woman had a series of fractures in her ribs, feet, left arm and right hip. Her doctor had her take vitamin D supplements, but they had no effect: Lab tests revealed that she didn’t have any vitamin D circulating around in her blood. | Then, about eight years later, the woman had a series of fractures in her ribs, feet, left arm and right hip. Her doctor had her take vitamin D supplements, but they had no effect: Lab tests revealed that she didn’t have any vitamin D circulating around in her blood. |
That seemed impossible. Some vitamin D, after all, is thought to be essential for maintaining bone health, and taking supplements after a bone injury or fracture is commonly used to expedite the healing process. Why was none of this vital substance in the woman’s system? | That seemed impossible. Some vitamin D, after all, is thought to be essential for maintaining bone health, and taking supplements after a bone injury or fracture is commonly used to expedite the healing process. Why was none of this vital substance in the woman’s system? |
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A medical geneticist who looked at this case, Dr. Patrick Ferreira, suspected that a binding protein that partners with vitamin D to get in and around the body — or a lack of it — might have something to do with this medical mystery. But losing the ability to transport vitamin D would be lethal to humans, according to what doctors conventionally know. | A medical geneticist who looked at this case, Dr. Patrick Ferreira, suspected that a binding protein that partners with vitamin D to get in and around the body — or a lack of it — might have something to do with this medical mystery. But losing the ability to transport vitamin D would be lethal to humans, according to what doctors conventionally know. |
Dr. Ferreira set out to test his hypothesis, but had trouble confirming that the vitamin D binding protein was indeed missing in the woman’s system. He and others sent blood samples to labs in Europe and Vancouver, but these tests — which can be unreliable — came back saying that binding protein levels were normal. When Dr. Ferreira retired, he passed the patient’s case to his colleague, Dr. Julien Marcadier, a clinical geneticist at Alberta Children’s Hospital Research Institute, now the lead author of a case report published last month in The New England Journal of Medicine. | Dr. Ferreira set out to test his hypothesis, but had trouble confirming that the vitamin D binding protein was indeed missing in the woman’s system. He and others sent blood samples to labs in Europe and Vancouver, but these tests — which can be unreliable — came back saying that binding protein levels were normal. When Dr. Ferreira retired, he passed the patient’s case to his colleague, Dr. Julien Marcadier, a clinical geneticist at Alberta Children’s Hospital Research Institute, now the lead author of a case report published last month in The New England Journal of Medicine. |
Fortunately for Dr. Marcadier, researchers at the University of Washington in Seattle had just developed a more sensitive method of detecting the protein. | Fortunately for Dr. Marcadier, researchers at the University of Washington in Seattle had just developed a more sensitive method of detecting the protein. |
Dr. Andrew Hoofnagle and his colleagues agreed to examine the blood sample, and found that there was no vitamin D in her blood, or any vitamin D binding protein. | Dr. Andrew Hoofnagle and his colleagues agreed to examine the blood sample, and found that there was no vitamin D in her blood, or any vitamin D binding protein. |
“When you think about the biology of vitamin D,” Dr. Hoofnagle said, “that shouldn’t work. That person should not be alive.” | “When you think about the biology of vitamin D,” Dr. Hoofnagle said, “that shouldn’t work. That person should not be alive.” |
Martin Hewison, a molecular endocrinologist at the University of Birmingham in England, who was not involved in the study, says that this case is the first of its kind. | Martin Hewison, a molecular endocrinologist at the University of Birmingham in England, who was not involved in the study, says that this case is the first of its kind. |
How could this woman have lived nearly six decades without a substance considered essential to human life? | How could this woman have lived nearly six decades without a substance considered essential to human life? |
While vitamin D binding protein sequesters vitamin D in the body, it’s the unbound molecules of vitamin D that are ultimately important for bone growth. | While vitamin D binding protein sequesters vitamin D in the body, it’s the unbound molecules of vitamin D that are ultimately important for bone growth. |
“The amount of vitamin D that is needed may vary by organ,” said Dr. JoAnn Manson, an endocrinologist and principal investigator of the Vitamin D and Omega-3 Trial at Brigham and Women’s Hospital in Boston. In this case, the amount of free vitamin D that this woman received from her diet or exposure to sun may have been sufficient to develop her bones and keep them alive. | “The amount of vitamin D that is needed may vary by organ,” said Dr. JoAnn Manson, an endocrinologist and principal investigator of the Vitamin D and Omega-3 Trial at Brigham and Women’s Hospital in Boston. In this case, the amount of free vitamin D that this woman received from her diet or exposure to sun may have been sufficient to develop her bones and keep them alive. |
And there’s still a question of exactly how much vitamin D our bodies need, although some recent research suggests that the dose of vitamin D might not matter much for bone mineral density, fractures or falls for the elderly. | And there’s still a question of exactly how much vitamin D our bodies need, although some recent research suggests that the dose of vitamin D might not matter much for bone mineral density, fractures or falls for the elderly. |
“I don’t think this makes a strong case for the need for less vitamin D, but simply how well the body can adapt to limited vitamin D binding protein,” said Ellen Fung, director of the Bone Density Clinic at Children’s Hospital Oakland Research Institute in California, “although ultimately it caught up with her.” |
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