Vitamin D

I haven't written too much on nutrition lately, so here's a little info on one of my favorite vitamins!

Vitamin D is found in significant levels in numerous dietary sources such as fish, eggs, fortified milk, and cod liver oil (yum!). Daily sun exposure also contributes significantly to the daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. In fact, it is believed that the general fear of sun exposure and its accompanying skin cancer risk has led to an increasing rate of Vitamin D deficiency.

The major biologic function of Vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. Recently, research also suggests Vitamin D may provide protection from osteoporosis, hypertension, cancer, and several autoimmune diseases.

There are so many potential benefits to the consumption of Vitamin D, and so many risks associated with a deficiency of it, that I could write pages and pages on the subject. Hmmm, I may have a new idea for a book!

Vitamin D is included in most multivitamins, usually in strengths from 50 International Units (IU) to 1,000 IU as softgels, capsules, tablets, and liquids. The Adequate Intake (AI) levels have been established by the U.S. Institute of Medicine of the National Academy of Sciences.

Recommendations are:

• 5 micrograms (200 IU) daily for all individuals--males, female, pregnant/lactating women--under the age of 50 years-old.
  
• For all individuals from 50-70 years-old, 10 micrograms daily (400 IU) is recommended.
  
• For those who are over 70 years-old, 15 micrograms daily (600 IU) is suggested.

Some authors have questioned whether the current recommended adequate levels are sufficient to meet physiological needs, especially given our society's general lack of fitness and "outdoorsmanship".

The upper limit (UL) for Vitamin D has been recommended as 2,000 IU daily due to toxicities that can occur when taken in higher doses.

Whenever possible, I opt to consume any nutrients, vitamins, et al from whole foods. For a list of foods highest in Vitamin D, click HERE.

Now, if it isn't too late, go get in that swim you've been avoiding all day. Hopefully there's still a little sunlight left. If not, enjoy your cod liver oil tonight!