Subpar levels of vitamin D a global problem
(NaturalNews) Although researchers are becoming increasingly aware of just how important vitamin D is to human health, deficiency and insufficiency remain common, according to a global survey conducted by Dutch researchers and published in The Journal of Steroid Biochemistry and Molecular Biology in 2010.
Researchers have long known that vitamin D is essential for the formation and maintenance of healthy bones and teeth. In recent years, however, study after study has confirmed a critical role for vitamin D in regulating the immune system and other important bodily processes. Studies have also shown that levels sufficient to protect against rickets might still lead to chronic diseases such as cancer, cardiovascular disease, diabetes and autoimmune diseases such as type 1 diabetes, multiple sclerosis or rheumatoid arthritis. In contrast, higher vitamin D intake can help prevent or even possibly cure such conditions.
Sunlight is key
In the 2010 review, the researchers note that 50 to 90 percent of a person's vitamin D is produced in their skin upon exposure to ultraviolet radiation from sunlight. The rest comes either from the diet or from supplements. The researchers concluded that the major variables affecting vitamin D blood levels are latitude, time spent in the sun, skin pigmentation (darker skin absorbs vitamin D more slowly) and ultraviolet-blocking behaviors such as covering the skin with sunblock or clothing. The researchers surveyed levels of vitamin D deficiency and insufficiency around the world and sought to explain them using these variables.
They found that deficiency is "very common" in the Middle East and correlates highly with the practices of avoiding sun exposure or wearing highly covering clothing. Likewise, they found that moderate or poor vitamin D status is "common" in Africa and speculated that this may be due to darker skin tones and cultural avoidance of sun exposure.
Although numerous studies have described vitamin D deficiency in North America as widespread, the Dutch researchers described the situation there as "much better" than in other regions, largely due to fortification of milk and high levels of supplement consumption.
In Europe, the researchers found notably less deficiency in northern countries than in Mediterranean ones and attributed this to difference in skin tones, sun-seeking behavior and cod liver oil consumption. Poor vitamin D status was more common among non-European immigrants, particularly pregnant women. In Australia and New Zealand, Asian immigrants were more likely to suffer from deficiency or insufficiency, as were children of vitamin D-deficient mothers.
Although vitamin D deficiency was described as "highly prevalent" in China and India (which the researchers did not explain), vitamin D status in Japan and southeast Asia was described as "better."
Overall, the best levels seem to have been found in Latin America, where the researchers described vitamin D status as "usually... reasonable."
The researchers concluded that in all parts of the world, vitamin D insufficiency and deficiency continue to be very common, particularly among high-risk groups including immigrants, pregnant women, young children and the elderly.
According to William B. Grant, director of the Sunlight, Nutrition, and Health Research Center (who was not involved in the study), the best way to improve your vitamin D status is to get more time in the sun. Grant says that people should expose "as much of the body as possible without sunscreen near solar noon, the time when one's shadow is shorter than one's height, for 10-30 minutes depending on skin pigmentation, being careful not to turn pink or red or burn."
"With whole-body exposure to the sun, one can make at least 10,000 IU/day in a short time," he said.