Vitamin D is a fat soluble vitamin that is produced primarily from sun exposure on the skin. It plays a critical role in the absorption of calcium from the digestive tract. Calcium is extremely important for maintaining bone mass but also plays an important role in every cell in the body. However, we also know that Vitamin D influences over 1000 genes in the body and is being considered a “hormone” by many in the medical community.
What is low? Per the medical literature, vitamin D levels in the blood < 20 are “deficient”, < 30 is “insufficient” and optimal is somewhere between 60-100 Consider these statistics:
- having levels over 40 reduces your risk or all cancers by 35%
- having levels over 50 reduces your risk of breast cancer by 83%
- having levels over 44 reduces your risk of colon cancer by 70%
- having levels over 52 reduces your risk of diabetes by 66%
- having levels over 50 reduces your risk of fracture by 50%
- having levels over 54 reduces your risk of multiple sclerosis by 54%
Typically when I check 25-OH Vitamin D levels on patients who are not supplementing with Vitamin D they are in the 28-38 range (and I live in Southern California where the sun shines 360 days per year) Why is this the case? People simply do not spend enough time in the sun because of work, fear of skin cancer or they just hate to take their shirt off in public. I started supplementing with Vitamin D 5000IU per day last year and my levels were still only 46.
Can you get vitamin D in food? Yes, but it is very difficult to get adequate amounts. On whole egg has 20 IU, fortified milk (1 cup) 100 IU, 3 ounces of salmon has 360 IU. Consider that to bring your levels above 60 you may need to take 5000-10,000 IU/day it is almost impossible to get there with food. 3 ounces of herring and one TBSN of cod liver oil have approximate 1300 IU.
The sad truth is that in residency training, very little time is given to checking vitamin D levels. In fact, I don’t think I ever checked a vitamin D level in my internship period. To me that is sad because so much of being a good doctor is in preventing disease. Unfortunately we get very good at treating disease, but terrible at preventing it.
Here is the bottom line for those of you that want the cliff notes version: have your doctor check your vitamin D levels (25-OH Vitamin D) and supplement daily if less than 60.