Now that the holiday season is coming up, the daylight is beginning to fade earlier, the weather is getting colder, and people are more inclined to stay indoors with their families and loved ones. While that’s certainly well and good for this time of year, it can have a negative impact on one vitamin of particular importance to general health.
Vitamin D isn’t a particularly common vitamin in food sources unless they’ve been fortified such as in milk and orange juice. A notable exception to this is liver, as the liver is what stores vitamin D. Thankfully, our bodies are able to make our own vitamin D in the skin using ultraviolet light from the sun. Traditionally, this is the method people have gotten the vast majority of their vitamin D. However, since its creation is sunlight dependent, the short days, wanting to stay indoors, and the sunlight being more indirect when we do have it all contribute to reduced vitamin D production in many individuals during the winter months.
Why do we need to make sure we get enough vitamin D though? One of its main roles and the reason why it’s often fortified in milk or along with calcium in orange juice is that it allows our bodies for properly absorb calcium. A vitamin D deficiency can lead to early osteoporosis and osteomalacia in adults or rickets in children. There’s also some evidence that it prevents cardiovascular incidents such as heart attacks and strokes, as well as having some protective effects again certain types of cancer. Finally, and especially relavent considering the holiday season is also cold and flu season, vitamin D supplementation has been shown to reduce the occurrences and severity of colds and flus.
There are a few things one should know when it comes to vitamin D supplementation, however. First off, is when looking for vitamin D as a supplement, make sure to look for vitamin D3. There are other forms of vitamin D ranging from D1-D5, with D4 in particular also being common, but only D3 has been found to be active in the body. If you can’t find D3 anywhere on the label, assume that it isn’t as there’s plenty that will say it on the label, making it easy enough to find. Second is, of course, the dosage. The typical recommended daily dose for individuals aged 1 to 70 years of age is 600 IU while those less than one should have 400 IU and those above 70 should aim for at least 800 IU. Generally speaking, during the winter months, natural production is decreased and so higher levels may be warranted and still greater amounts in the case of a deficiency. 5000 IU is a pretty common and acceptable amount for adults past the age of 9, while 4000 IU is typically recommended. For children between 1 and 9 years 3000 IU is suggested and infants not more than 1000 IU. Unsafe amounts would require approximately 50,000 IU per day for an extended period of time.
I hope you all have a safe and enjoyable holiday season and remember to stay active.
--Joshua J. J. Jorde D.C.