How much Vitamin D do you really need?

Vitamin D is a hormone that helps maintain normal blood levels of calcium and phosphorus.  It is used, alone or in combination with calcium, to increase bone mineral density and decrease fractures because calcium helps to form and maintain strong bones.

Our bodies produce Vitamin D when struck by ultraviolet rays from the sun.  Curiously, very few foods found in nature contain it. The flesh of fatty ocean fish, such as salmon (447 IU per serving), tuna (154 IU) and mackerel (388 IU), as well as fish liver oils (1 Tbsp has 1,360 IU) are considered to be the best sources.  Beef liver, cheese, and egg yolks are other sources which contain small amounts. Vitamin D in these foods is primarily in the form of vitamin D3 and its metabolite 25(OH)D.  Certain mushrooms contain vitamin D2 in variable amounts. While other mushrooms are enhanced with ultraviolet light to increase their levels of vitamin D2.

There is a Vitamin D deficiency epidemic in our country.  Researchers at Albert Einstein College of Medicine of Yeshiva University found that seven out of ten children in the United States are deficient in Vitamin D.  Dr. Melamed, the lead researcher in the study said, “It would good for them [parents] to turn off the TV and send their kids outside. Just 15 to 20 minutes a day should be enough. And unless they burn easily, don’t put sunscreen on them until they’ve been out in the sun for 10 minutes, so they get the good stuff but not sun damage.”  This deficiency is connected to pediatric infections.  While, another study shows that low levels of Vitamin D are associated with lower respiratory infections in infants. 

The higher incidence in respiratory infections with people with lower levels of Vitamin D is not confined to infants.  Finnish men serving on a military base who had serum levels of Vitamin D less than 40 nmol/L were shown to have greater rates of respiratory infections.  Another study of 18,000 people showed that lower levels of 25(OH)D have higher rates of upper respiratory infections

Other studies showed lower levels of Vitamin D were associated with higher rates of cancer, multiple sclerosis, and even death.  520,000 Western Europeans in one large study found that higher levels of 25(OH)D are correlated with lower rates of colorectal cancer.  Another study of 57,000 participants showed that low levels of Vitamin D in the body were associated with higher mortality.  At the 23rd Meeting of The European Neurological Society a paper was presented which demonstrated that low levels of Vitamin D were correlated with Multiple Sclerosis

Vitamin D can cause adverse effects if too much is taken.  It also found that 50,000 IU per week was a safe level of supplementation (which is a little over 7,000 IU per day) for the 44 patients in the study of supplementation in MS patients.  No evidence of overdose of Vitamin D was found.  This paper found that 10,000 IU per day is the limit, another study shows that 40,000 IU would be the upper limit as this would cause hypervitaminosis D.

The best test for determining your levels of Vitamin D is the serum 25(OH)D  This graph shows that levels below 60 nmol/L would indicate low levels of Vitamin D.  60-200 nmol/L is the sufficient range for Vitamin D levels in the blood.  Toxicity would be determined by over 500 nmol/L  Other studies show that 75 nmol/L prevents fractures in older adults.  3800-5000 IU per day have been suggested to reach that level.  Another set of guidelines is seen at this link.

It should also be noted that people with darker skin and especially those whose ancestors were from Africa are more at risk for having Vitamin D deficiencies.  Those who have Northern European ancestry metabolize Vitamin D from sun exposure with greater ease.

So, how much Vitamin D do you need?  There is only one way to know for sure.  Ask your doctor or health care provider to order a serum 25(OH)D test.  That way you will know for sure what your levels are and how much Vitamin Dyou really need.  Don’t guess, and don’t take supplements without knowing what you really need.

Eric Waltemate, DC, LAc (IN)
14 Park Place Suite A

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