These days, vitamin D is a hot topic. It’s in all of the health magazines and front and center on health food shelves. Most doctors are testing us for it, and most of us are turning up low on this hormone. (Yes, hormone…)
So, what DOES vitamin D do? What do we need to know about deficiencies and supplementing vitamin D?
What is vitamin D?
It is a fat soluble vitamin that is actually a steroidal hormone that is made when the fat in your skin is exposed to UV rays from the sun. There are 2 types of vitamin D. D2 and D3. Vitamin D2 is more commonly found in plant foods, while vitamin D3 is found in fatty fish and animal products.
Who is at risk for deficiency?
Older women, infants, obese individuals, people who live in colder and northern exposure areas, people who do not consume fish in their diets regularly, those who wear sunscreen while in the sun, and people with higher levels of melanin in their skin. Incidence rates for vitamin D deficiency is >80% in black communities and 75% in hispanic communities!
How is a deficiency diagnosed and what are the symptoms?It is diagnosed by a blood test. In my clinic, I test for vitamin D and parathyroid hormone (PTH). Since there is such a high incidence of vitamin D deficiency, this will be reflected in the reference ranges, since reference ranges are only statistical norms and NOT optimal ranges! This means that while a typical reference range may by 20-100 nmo/L, optimal ranges that have been shown to prevent disease is actually 50-70 nmo/L. So, just because testing falls within the reference range does not indicate that there is optimal vitamin D!The symptoms that people who are deficient in vitamin D may experience include:
- Bone pain or muscle twitching or muscle weakness
- Frequent illness, especially of a respiratory nature
- Stress fractures
There are risks to deficiencies that are published in the medical literature that may not be well known. These include:
- Intestinal lining junction permeability leading to food sensitivities and systemic inflammation
- Increased risk of developing autoimmune diseases such as MS, fibromyalgia, type 1 diabetes.
- Increased severity of symptoms in people with an autoimmune disease
- Lowered immunity to viral illness.
- Worsened severity of viral illness. Multiple studies show worse outcomes with severe flu and COVID in those with low vitamin D levels.
- Increased rates of heart disease
- Osteopenia, osteoporosis, and fracture.
And one more benefit! … Adequate vitamin D levels may support weight loss! In one study, people on a diet AND taking vitamin D supplements lost more weight than the diet group alone. Another study looking at people taking vitamin D and calcium supplements had similar results.
Should you supplement?
If someone has a suboptimal vitamin D level, in my practice, I recommend supplementation. I typically recommend vitamin D3 at 5,000 IU per day to treat a deficiency and 2,500 Iu per day to maintain levels.
I do not typically recommend the prescription vitamin D2 50,000 IU weekly supplement that can be covered by insurance for the following reasons:
- It is not converted to the usable form (D3) by a moderate amount of people and in this case does not raise levels.
- Very high bolus doses like this can cause hormonal imbalance symptoms such as hot flashes and poor sleep.
- It is difficult to titrate for a maintenance dose.
Can I just eat a vitamin D rich diet?
You should certainly plan to include more vitamin D rich foods in your diet, both to prevent and treat a deficiency. These foods include salmon, mackerel, sardines, cod liver oil, canned tuna, shrimp, egg yolk, beef liver, mushrooms, milk, and yogurt. Food alone is unlikely to treat a deficiency, especially in a bariatric patient with limited food volume intake.
The bottom line is that vitamin D has a huge role in our health and should be tested and supplemented if needed. The best absorbed vitamin D form is vitamin D3 taken in moderate daily doses.