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And those chuckles you hear at the nurses station may have their origins in sufficient Vitamin D3 synthesis. According to reports in Science Daily, the study led by Rana Zadeh, assistant professor of design and environmental analysis, also determined that the nurses who had access to more natural light on the job "communicated more often with their colleagues, laughed more and served their patients in better moods than nurses who settled for large doses of artificial light."
A study published in the Journal of Obstetrics and Gynecology of India also praised the powers of increased vitamin D levels. It underlined benefits ranging from improved muscle performance that can help people avoid falls to ample Vitamin D being an "important factor in prevention/treatment of some forms of cancer, osteoporosis, rheumatoid arthritis, multiple sclerosis, hypertension, cardiovascular disease, obesity, psoriasis, and psychiatric diseases... The higher the Vit D level, the lower the risk of cancer."
Sadly, some nurses and workers with similar work schedules tend to be the most likely to be deficient in vitamin D3, according to Zadeh's study. "Although there is considerable variability among different findings, there is compelling evidence to suggest that shiftworkers and particularly those who work fixed night shift patterns, have a strong predilection toward vitamin D3 deficiency," it said.
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Other factors come into play, too, some of them having nothing to do with being a nurse. "People with darker skin are at greater risk of vitamin D deficiency because greater amounts of melanin in the skin reduce the skin's ability to produce vitamin D from sunlight," noted the Mayo Clinic. "Aging also decreases the efficiency of vitamin D synthesis. Sunscreen, clothing and other UV protective measures that block skin's exposure to the sun not only help prevent skin cancer, but also reduce production of vitamin D."
If you live in a place with significant air pollution, that can also work against you. As the obstetrics study out of India explained, "Synthesis in the skin epidermis takes place over several days; the quantity (intensity) and quality (appropriate wavelength) of sunlight are both important... The deficiency can occur because of fat malabsorption, anticonvulsant use, chronic kidney disease, and obesity and is seen in high-risk groups like ... people from areas with a thick layer of ozone... and people from urban areas."
And when nurses don't get enough natural light to synthesize that Vitamin D3? The personal health penalties can mount up quickly, with negative impact on bone health just the most obvious. "It has also been linked with many other illnesses including autoimmune conditions, metabolic function, some cancers, and also psychiatric disorders," according to Science Daily coverage.
There is also a link between not getting enough natural light and Seasonal Affective Disorder.
But if you can't get natural sunlight at work, there are a few easily-accessible solutions, even for those who work the night shift. (The British trade union GMB called for all night shift employers to provide free Vitamin D doses for employees, but that's probably not going to happen here in the U.S.)
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According to Australia's Hospital and Healthcare website, for example, "night shift workers should consider taking 2000-5000 IU/d vitamin D3 and raising serum 25-hydroxyvitamin D levels to 40-60 ng/ml. This may help to compensate for the effects on bone density of reduced sun exposure."
If you make a point of spending some time outside during daylight hours, you may be able to pump up your levels with minimal exposure to harmful UV rays. "The body can produce enough vitamin D with as little as 10 minutes of unprotected sun exposure per day," registered dietitian and certified dietitian nutritionist Justine Roth told Women's Health.
You probably won’t require a blood test to see if you’re deficient, according to the Mayo Clinic. It recommended jumping straight to taking a supplement instead. "Even 600 international units a day will correct a deficiency fairly quickly," it said.
But as you would with any supplement, don't go overboard. Enough is good, but there is such a thing as too much vitamin D3. It can "overly increase your absorption of calcium, leading to problems such as kidney stones and damage to your heart and blood vessels," Mayo cautioned. "The National Academy of Medicine recommends an upper limit of 4,000 international units a day to be safe."