Where oh where did my Vitamin D go?

As I look out my window, I see snow falling from cloud covered skies. There is a peacefulness that surrounds snowfall. There is a quiet contentment that each of us experiences when it snows. Our worlds are forced to slow down and for a change we relax.

A few months ago, I would have been excited to see the snow. But today, when I woke up to snow falling, I was sad. I didn't like it. After two months of wintry weather, I was tired of the clouds and tired of the snow. Something seemed like it was missing. I wanted to see the sun.

We all experience a boost of mood and energy when we see the sunlight and feel its warmth on our skin. It is now known that this boost is often the result of the vitamin D our body produces from being in the sun.

The main symptoms of vitamin D deficiency are fatigue and depression, especially in the winter months. Recent research has demonstrated that most individuals living in the US are deficient in vitamin D. Although many foods are now fortified with vitamin D, the majority of vitamin D we receive is through sunlight. Individuals living in higher latitudes have less sun exposure and therefore are more susceptible to deficiency. In addition, those people living in sunnier locations may still be vitamin D deficient since the application of sunscreen prevents the conversion of active vitamin D. So what are we to do? In most cases, taking a vitamin D supplement becomes the fastest and most effective way to increase levels of vitamin D.

It appears that vitamin D functions more like a hormone than a vitamin. The main functions of vitamin D involve calcium absorption from the intestines and maintaining serum calcium and phosphorous levels. It is now known that vitamin D plays many more roles in the body as well. Vitamin D has been shown to enhance immune function, reduce inflammation, protect against cardiovascular disease, prevent autoimmune conditions, and control the way cells multiply and transform. Therefore, vitamin D may be beneficial for several conditions including colds/flu, asthma, cancer, multiple sclerosis, cardiovascular disease (heart disease, high cholesterol), stroke, high blood pressure, depression, chronic pain, osteoporosis, rheumatoid arthritis, inflammatory bowel disease, and diabetes.

Blood testing for 25(OH) D (a vitamin D precursor in our blood) is the best indicator of vitamin D status. This marker should be the only one used to diagnose vitamin D deficiency. Close monitoring through blood testing of 25(OH) D levels should be done at least two to three times per year to ensure adequate supplementation and avoid toxicity. These levels should be at least 40 ng/ml but not exceed 70 ng/ml year round for optimal health benefits.

Research has shown that healthy individuals use about 3000-4000 IU of vitamin D daily, leaving the recommended daily allowances far below what may be required. Optimal vitamin D dosage varies depending on several factors including age, sun exposure, gender, weight, and skin color. The current recommended daily allowance for vitamin D is 200 IU for those between the ages of birth-50, 400 IU for those 51-70 years, and 600 IU for those 71 years of age and older. In most cases, the RDA is enough to prevent frank vitamin D deficiency and rickets. However, it may not be sufficient to maintain optimal health. It is estimated that 20-30 minutes of sun exposure during the middle part of a summer day can produce between 10,000 and 50,000 IU of vitamin D! Many practitioners use doses of 2000–7000 IU per day as treatment for individuals shown to be deficient.

Two forms of vitamin D supplements are available – vitamin D3 (cholecaciferol) and vitamin D2(ergocalciferol). Vitamin D2 is not human vitamin D and is not normally found in humans. In addition, intake of vitamin D2 may produce metabolic by-products not normally present in humans. There is some controversy, however, as recent research has shown that vitamin D2 may be as effective as vitamin D3 at maintaining blood levels of vitamin D. Considering vitamin D3 is the human form of vitamin D, I believe that this form should be used over vitamin D2. However, more research is required to determine if one form is superior to the other.

Vitamin D can be toxic so it is important to talk to your doctor before beginning supplementation. I screen all of my patients for vitamin D deficiency especially before beginning treatment. Let your doctor know you want to have your vitamin D levels tested to see if you are deficient. Although there is no substitute for the sun, ensuring adequate vitamin D levels can make an immediate difference in your overall health and attitude.


-Dr. John