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The Importance of Vitamin D

MDCustomRx - Quality Matters

Vitamin DBy Krista Borowski, RPh
Vitamin D is a fat-soluble vitamin that has several important functions, including regulating the absorption of calcium and phosphorous for proper development of strong bones and teeth. If your body doesn’t get enough vitamin D, you are at risk of developing bone abnormalities such as soft bones (osteomalacia)or fragile bones (osteoporosis). Vitamin D has other roles in the body and may help to:

  • Support cardiovascular health and lung function
  • Regulate insulin levels and aid in diabetes management
  • Reduce inflammation and modulate autoimmune disorders
  • Support the health of the immune system, brain and nervous system
  • Lower cancer risk

Vitamin D is produced when UVB rays from the sun convert cholesterol on the skin into vitamin D3, which is then converted into 25-hydroxyvitamin D3 in the liver. The kidneys then convert this into the active form of vitamin D, called calcitriol. There are varying guidelines on how much sun exposure one needs for vitamin D production. The Vitamin D Council recommends exposing as much skin as possible to the sun for half as long as it takes to turn pink. This could be 15 minutes for a very fair skinned person, or a couple of hours or more for a dark skinned person.

Lifestyle and environmental factors that may affect your ability to get enough vitamin D through sunshine alone include the use of sunscreen, time spent indoors, amount of skin exposed, time of day, cloud cover, smog and skin melanin content. These factors may lead to a vitamin D deficiency. Symptoms of vitamin D deficiency in adults may be vague but can include overall feeling of malaise, possibly accompanied by general aches and pains.  A blood test to measure 25-hydroxyvitamin D can be done to determine if you are getting enough vitamin D. The following are Vitamin D 25(OH)D guidelines of various organizations according to the Vitamin D Council:



Vitamin D Council Endocrine Society Food and Nutrition Board Testing Laboratories
Deficient 0-30 ng/ml 0-20 ng/ml 0-11 ng/ml 0-31 ng/ml
Insufficient 31-39 ng/ml 21-29 ng/ml 12-20 ng/ml  
Sufficient 40-80 ng/ml 30-100 ng/ml >20 ng/ml 32-100 ng/ml
Toxic >150 ng/ml      

The following are recommended daily intakes taken from the Vitamin D Council:

  Vitamin D Council Endocrine Society Food and Nutrition Board
Infants 1,000 IU/day 400-1,000 IU/day 400 IU/day
Children 1,000 IU/day per 25lbs of body weight 600-1,000 IU/day 600 IU/day
Adults 5,000 IU/day 1,500-2,000 IU/day 600 IU/day, 800 IU/day for seniors

The Vitamin D Council suggests that a level of 50ng/ml is the ideal level to aim for and recommends that adults take 5,000 IU/day of vitamin D supplement in order to reach and stay at this level. The Endocrine Society recommends taking a vitamin D supplement of around 2,000 IU/day to reach and stay above a level of 30ng/ml.

Lastly, the Food and Nutrition Board recommends 600 IU/day of vitamin D supplement because they believe 20ng/ml is the ideal level to aim for.

If you are low in vitamin D, your provider will likely want you to take a vitamin D supplement. As stated, it is not easy for everyone to get sufficient amount of daily sunshine and unlike other vitamins, it is very difficult to get the necessary amount of vitamin D from food sources. It is important to work with a knowledgeable health care professional in order to choose the best supplement for you, as there are a few medications and medical conditions that interfere with vitamin D. A healthcare professional will also know when to recheck a vitamin D level to make sure it is in the optimal range.  The pharmacists at MD Custom Rx can help you with Vitamin D testing and supplementation – Talk with us today!

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