According to a research conducted by UC Irvine and Mayo Clinic researchers, vitamin D levels in Americans is highest in the month of August and lowest in the month of February.
Vitamin D is an essential nutrient for healthy bones and is produced in the skin upon exposure to ultraviolet B rays from the sun. This nutrient helps bones absorb calcium, which is known to strengthen the bones. Vitamin D also acts as protection against osteoporosis and also protects the body from seasonal aliments like flue. Lack of Vitamin D in the body is known to affect the "innate immunity" of a person's body, which is the first line of defense against germs.
Basking in the sun in summers is the best way to attain adequate amounts of Vitamin D, food items like egg yolks and oil-rich fish like mackerel, salmon, sardines, herring, milk and cereal are also good sources of Vitamin D.
"Even with food fortification, vitamin D levels in the population show a high level of seasonality due to the influence of sunlight," said Amy Kasahara, a UC Irvine graduate student in public health and first author of the paper in a press release. "The exact biochemical pathways from UVB rays to vitamin D were discovered in the 1970s. In this study, we have shown that vitamin D levels lag the solar cycle, peaking in August and troughing in February."
The conclusion of the study was derived after researchers analyzed the level of Vitamin D in 3.4 million blood samples collected weekly in the United States between July 2006 and December 2011.
Andrew Noymer, associate professor of public health and senior author of the article concluded that though the correlation between seasons and levels of Vitamin D in the body has been known for some time now, this new study puts "a lot more precision on the estimates of vitamin D seasonality."
