Monday, February 6, 2012

Vitamin D Do-Daa!

Let's talk about the infamous sunshine vitamin, Vitamin D! Vitamin D is an important and powerful nutrient in our bodies. It's cool because not only can we get it from the foods we eat but our body can make it with adequate exposure to sunlight. WOW, right?
   
*Note: Sunlight must be in a specific wavelength range in order for our bodies to be able to use it to make    Vitamin D. This range occurs daily in the tropics, however only during the spring and summer months in most of the United States. So during the winter if you don't have a UV light to sit in front of, you must consume Vitamin D to get it in adequate amounts.
So where can you get Vitamin D?
Vitamin D is a fat soluable vitamin, so most of the time it is found in certain fatty foods such as milk, fish, egg, beef liver, cod liver oil, and for vegans in irradiated mushrooms and yeast. There are also many products available in stores that have Vitamin D fortification such as milk or orange juice. However, there are also supplements on the market that come in a variety of amounts, flavors, and even forms. I personally think the D3 liquid drops are the easiest to use, but have heard that many people like the flavored forms as well.
Another way to get some (but not all of your daily intake) Vitamin D is from sunlight exposure, however during the winter months sun exposure isn't in the correct range for Vitamin D benefits. Most people only need 10-30 minutes of sun exposure 2-3 times per week for adequate sun exposure for Vitamin D benefits, however this is with skin exposure with NO sun screen. Alternately, UV lights can be used indoors during the winter months to get your daily intake. If you have a family history or increased risk of skin cancer, you should talk to your doctor first before using sunlight or UV lights as a Vitamin D method.

How much is enough? 
There is a lot of controversy on how much your daily value of Vitamin D should be, due to new research that is showing that Vitamin D has protective effects against cancer and other health conditions and in deficient amounts can exacerbate conditions such as obesity, glucose/insulin dysfunction, and even cause diabetes. The best way to determine if you are getting enough Vitamin D is to have your doctor do a serum blood test for 25- hydroxyvitamin D or 25(OH)D. Levels of 50 ng/mL or 125nmol/L or higher reveal beneficial effects, however current thresholds are outdated with levels at 30ng/mL being adequate. If the standard threshold was raised today, 90% of Americans would be Vitamin D deficient!

Currently the United States Institute of Health (by dietary intake only) recommends the values in the tables below, however many health care and nutritional advocates recommend double to triple that amount for real benefits. Generally speaking, Vitamin D intake needs to increase based on body mass and thus a better guideline might be obtained by using the daily maximum (Tolerable Upper Intake Levels) as an amount not to exceed for your age group. I usually recommend 1000 to 2000 IU/day for most of my patients, however you need to consult your doctor before beginning a regiment.

**The below values were obtained from the Institute of Health, but some medications can cause interactions so consult your doctor before taking any new supplements.


Recommended Dietary Allowances (RDAs) for Vitamin D 
AgeMaleFemalePregnancyLactation
0–12 months*400 IU
(10 mcg)
400 IU
(10 mcg)
  
1–13 years600 IU
(15 mcg)
600 IU
(15 mcg)
  
14–18 years600 IU
(15 mcg)
600 IU
(15 mcg)
600 IU
(15 mcg)
600 IU
(15 mcg)
19–50 years600 IU
(15 mcg)
600 IU
(15 mcg)
600 IU
(15 mcg)
600 IU
(15 mcg)
51–70 years600 IU
(15 mcg)
600 IU
(15 mcg)
  
>70 years800 IU
(20 mcg)
800 IU
(20 mcg)
  

* Adequate Intake (AI)
Tolerable Upper Intake Levels (ULs) for Vitamin D 
AgeMaleFemalePregnancyLactation
0–6 months1,000 IU
(25 mcg)
1,000 IU
(25 mcg)
  
7–12 months1,500 IU
(38 mcg)
1,500 IU
(38 mcg)
  
1–3 years2,500 IU
(63 mcg)
2,500 IU
(63 mcg)
  
4–8 years3,000 IU
(75 mcg)
3,000 IU
(75 mcg)
  
≥9 years4,000 IU
(100 mcg)
4,000 IU
(100 mcg)
4,000 IU
(100 mcg)
4,000 IU
(100 mcg)


Why do I need Vitamin D?
Vitamin D deficiency has been linked with higher mortality rates, increased incidence of low bone mass and falls, immune system dysfunction, higher rates of multiple sclerosis, higher rates of certain cancers,  higher rates of vascular disease, higher rates of autoimmune disorders such as rheumatoid arthritis, Parkinson's disease, Alzheimer's Disease, and many other health conditions.
Vitamin D is responsible for calcium absorption from the intestine, maintenance of calcium and phosphorus levels in the blood, maintenance of bone health and bone cell support, adrenal function and health, cell function and differentiation, immune system support, and many other actions that aren't fully understood by scientists yet. As you can tell, Vitamin D is important to maintain your body's health and function but also to help prevent many health conditions and aging processes.