Vitamin D has always been a nutrient known for its role in bone health, helping promote calcium absorption. More recent research strongly suggests it also helps boost the immune system and reduce inflammation. Meaning, in addition to helping fight the cold and flu, research is looking into what role vitamin D may play in reducing risk of several types of cancer and autoimmune disorders. In the role of reducing inflammation, it may help reduce risk of heart disease and maybe even some forms of arthritis.
Where do we get vitamin D?
The most common source is the sun! We synthesize vitamin D in our skin. Lucky for us in New Mexico since we have over 300 days of sunshine a year. Despite Florida’s claim of being the “sunshine” state, we are the fourth sunniest state, following Arizona, California and Nevada, based on meteorological data. People who live north of the 42nd parallel don’t have enough UV energy between November and February to do the job. The “Big-I” in Albuquerque is at 35.10…degrees. Santa Fe Plaza is at 35.68…., Taos Plaza: 36.40…., Farmington: 36.70…, and Raton: 36.80. Latitudes south of the 35th parallel are good year-round. However, windows, sunscreen, clouds and clothing do block out the benefits of the sun when it comes to the vitamin D synthesis. [Pollution also blocks the benefits, but we don’t have much of that in New Mexico to make an impact.] So, in the winter let’s get outside regularly, even on our chilly days, and take advantage of that sunshine.
What about food sources? There aren’t many. Vitamin D is added to milk, some yogurt, breakfast cereal, and juices. As the vitamin D issue is becoming more prevalent, don’t be surprised to find it added to more foods. It is found naturally in egg yolks, liver, fatty fish (salmon, tuna, sardines) and in some mushrooms. The problem it that you can’t really know how much is in your food because it isn’t one of the nutrients required on Nutrition Facts labels.
Despite living in such a sunny state, when people have their vitamin D level measured, specifically serum (blood) hydroxyvitamin D [25(OH)D] concentration, they are finding they have low levels. Whether you get your vitamin D levels tested is between you and your primary care provider, but make sure you are getting enough vitamin D.
Vitamin D Recommendations
While New Mexico is a great source of vitamin D from the sun, if you aren’t outside on a regular basis, then you need to supplement. (In some cases, even if you are outside regularly, you could be low.) The current Adequate Intake (A.I) is: 200 I.U.* for everyone from birth to 50 years, 400 I.U. for 51-70 years, and 600 I.U. for 70+ years. This is admittedly low, and established in 1997 when all that was known about vitamin D was its role in bone health. A committee is currently reviewing the research and updating the national recommendations. Their findings and recommendations expected to be released in May 2010.
In November 2008, the American Academy of Pediatrics recommended that all children (from infants to adolescents) get 400 I.U. of vitamin D daily, as a supplement if necessary. For adults, it is generally recommended that one get 800 I.U. and 2,000 I.U. a day depending on the individual’s age, outdoor activity level, and their vitamin D test results if available. Clinical trials have found that upper limits of 10,000 I.U. /day can be consumed by people without harm (not being recommended here because I don’t know your health status).
Vitamin D is in multi-vitamins (I’ve found 600-1,000 I.U. in various multi’s), in calcium supplements (generally 400 – 500 I.U.). It is also available as a separate supplement to balance the amount in the multi-vitamin and/or calcium supplement to get the 800 – 2,000 I.U. needed. You cannot overdose from sun exposure.
*I.U. = International Units, the most common way vitamin D is sold and referenced.