Answering your questions
For some time now I've been interested in studies looking at a possible relationship between low levels of Vitamin D and chronic pain. Admittedly, some of my interest has been spurred by my own chronic pain condition. Since I am extremely sensitive to heat, I get very little sun. As a result, I've always suspected that I am low in vitamin D. So I wasn't surprised to find that a number of clinical researchers have found that vitamin D may play a role in various chronic pain conditions. Below are some of the most frequently asked questions about vitamin D and chronic pain.
What kinds of chronic pain can be related to insufficient Vitamin D?
Following is a summary of some of the research done relating to vitamin D and different types of chronic pain:
Musculoskeletal Pain - The largest group of studies seemed to look at vitamin D's relationship to chronic musculoskeletal pain. Dr. Stewart Leavitt did a comprehensive review of 22 clinical investigations of vitamin D in patients with chronic musculoskeletal pain. The studies were conducted in a variety of countries and included approximately 3, 670 adult patients from diverse age groups and ethnic backgrounds. In the 22 studies, on average approximately 70% of patients with pain were found to be deficient in vitamin D.
Neuropathy - In a study of 51 patients with type 2 diabetes who had painful diabetic neuropathy, three months of supplementation with 2000 IU/day of vitamin D resulted in a nearly 50% decrease in pain.
Inflammation - Studies have shown that vitamin D supplementation decreases pro-inflammatory cytokines and increases anti-inflammatory cytokines, suggesting that vitamin D may help to improve some painful chronic inflammatory autoimmune conditions like inflammatory bowel disease that are influenced by excessive cytokine activity.
Migraine Disease - Case reports have shown that two months of supplementation with vitamin D combined with calcium reduced both the frequency and intensity of migraines in post- and pre-menopausal women. Migraine specialist Dr. John Claude Krusz says he tests the vitamin D levels of all of his patients because he and many of his colleagues have begun to see low vitamin D levels in people with headaches and Migraines.
How do I know if I need more Vitamin D?
The only way to know for sure if your vitamin D levels are low is by a blood test. The test measures the level of 25-hydroxyvitamin D - abbreviated 25(OH)D - which is a metabolite of vitamin D. The median level of 25(OH)D is 60 ng/mL. Less than 30 ng/mL is deficient. On the other hand, a level higher than 150 ng/mL is potentially toxic.
What should I do if my Vitamin D level is low?
Talk with your doctor about how much and what kind of vitamin D you should take. The most recent recommendation for replenishing vitamin D is 5,000 IU per day. I spoke with two doctors and one nutritional specialist and all three agreed that they generally recommend that patients take 50,000 IU of vitamin D3 per week (approximately 7,000 IU per day) to replenish their levels. However, it's important that you talk with your doctor before starting to take supplements because a number of things can influence how effective the vitamin D will be in individual patients. For example, several different medications can reduce the potency of vitamin D. St. John's wort, excessive alcohol and tobacco smoking may reduce the effects of vitamin D. And very high doses of vitamin D should be avoided if your taking digitalis/digoxin or thiazide diuretics because of the risk of hypercalcemia.
Can't I get enough Vitamin D from sunlight and food sources?
Very few foods contain any vitamin D - only a few types of fish and dairy products that have been fortified. As a result, you cannot get adequate amounts of vitamin D from food.
Exposure to sunlight is the primary natural source for vitamin D. I've always heard that if you get enough sunlight, your vitamin D levels will be fine. But I'm learning that's not always the case. One of the doctors I consulted about this article told me he gets a lot of sunlight, yet when he was tested, his vitamin D levels were deficient.
As I mentioned above, other factors can influence how well your body utilizes vitamin D. In addition, certain groups of people are at higher risk of vitamin D inadequacy:
• Adults over 50. As we age, the skin cannot synthesize vitamin D as efficiently and the kidney is less able to convert it to its active hormone form.
• People with limited sun exposure. If you're homebound, wear clothing that covers most of your skin, or live in northern latitudes that get little sunlight part of the year, it's unlikely that you get adequate amounts of vitamin D.
• People with dark skin. The pigment melanin, which results in darker skin, also reduces the skin's ability to produce vitamin D from exposure to sunlight.
• People who have fat malabsorption problems. Vitamin D is fat soluble and therefore requires some dietary fat in the gut for absorption. Some medical conditions associated with fat malabsorption include some forms of liver disease, cystic fibrosis and Crohn's disease.
• People who are obese. Greater amounts of subcutaneous fat sequester more of the vitamin D and alter its release into the circulation.
• People who have had gastric bypass surgery. Part of the upper small intestine where vitamin D is absorbed is bypassed, which may lead to inadequate levels.
What kind of pain relief can I expect from supplementing Vitamin D?
In most cases, it is unrealistic to expect complete pain relief. Rather, the evidence suggests a range of potential improvements. What you are more likely to experience includes: partial pain relief, reduced pain intensity, less frequent pain, a reduction in muscle soreness or stiffness, improvement in the effectiveness of pain medications, reduction in the amount of pain medications required, and/or improvement in mood or overall quality of life.
It's also not realistic to expect quick results. While there have been reported cases of improvements in a week or two, it's more likely to take a few months. Neuralgia and bone-related pain may take about three months to improve; and muscle pain, weakness and fatigue can take six months or longer. It's recommended that you allow six to nine months to fully assess how effective or ineffective vitamin D supplementation has been.
Can I overdose on Vitamin D?
Although there are no reports in medical literature of a single excessive dose of vitamin D that was toxic or fatal in humans, very high doses - particularly over a period of time - can be toxic, and occasionally fatal. The length of time high doses are taken seems to be the key factor. Researchers have noted that as much as 10,000 IU a day have been tolerated well for up to five months, but the same dosage for six months was implicated as toxic. Once again, it is important to consult your doctor before taking high doses of vitamin D. And if you take high doses for an extended period of time, be sure to be retested periodically to make sure you're not approaching toxic levels.
What is the overall assessment of Vitamin D and chronic pain?
Vitamin D is not suggested as a replacement for other pain management techniques. However, current evidence suggests that supplementing vitamin D may help many patients who have been unresponsive to other pain therapies. The risks are minimal, the cost of testing is reasonable and the supplements are inexpensive, making it a favorable benefit-to-cost ratio. If you have a chronic pain condition, it would certainly be worthwhile to have your vitamin D levels checked.
Leavitt, MA, PhD, Stewart B. (2008).Vitamin D for chronic pain. Practical Pain Management, (July/August), [24-42].
"Dietary Fact Sheet: Vitamin D." Office of Dietary Supplements. 11 Sept 2009. National Institutes of Health.
© 2009 Karen Lee Richards