From healthcentral.com
Research has found people with psoriatic arthritis tend to be low in this essential vitamin—but the jury is out on whether a supplement can help
Psoriatic arthritis, an autoimmune disease fuelled by out-of-control inflammation, can cause symptoms like joint pain, fatigue, and swelling from head to toe, so it's no surprise that people might be looking for ways to get relief. And one option that has gotten some attention is vitamin D, which some consider to be one of the best supplements for psoriatic arthritis.
But in reality, the relationship between psoriatic arthritis and vitamin D is—as with a lot of supplements —a tricky one to figure out, since the science behind it is still unclear. What might be driving the correlation? Vitamin D is one of the most promising vitamins for psoriasis (a related but still separate condition that appears on the skin), so there’s reason to be optimistic. So, do psoriatic arthritis supplements like vitamin D merit a spot in your medicine cabinet? Here’s what the experts say.
The Relationship Between Vitamin D and Psoriatic Arthritis
The connection between vitamin D and psoriatic arthritis is more complicated than it seems. Vitamin D, for reference, benefits your body on several fronts. “It’s important for bone health and has roles in the immune system and in maintaining skin health,” says S. Louis Bridges, Jr., M.D., a rheumatologist and physician-in-chief and chair of the Department of Medicine at the Hospital for Special Surgery in New York City.
Research has found that vitamin D deficiency was especially common among people with PsA—and that the lower their vitamin D levels were, the more disease activity, indicated by a higher DAPSA (Disease Activity in Psoriatic Arthritis) score, they experienced. DAPSA is a measurement of PsA severity that takes into account the joints affected, pain levels, and levels of C-reactive protein, which is an inflammation marker.
But it’s unclear whether low vitamin D levels are the cause or the result of inflammation, according to Dr. Bridges. “When there is inflammation, serum levels of vitamin D decrease,” says Dr. Bridges. “Low levels of vitamin D are associated with a variety of inflammatory states.” In other words, it’s like which came first—low vitamin D, which contributes to the uptick in inflammation and DAPSA, or the inflammation, which stifles the levels of vitamin D? It’s hard to say.
Should You Take Vitamin D to Treat Your Psoriatic Arthritis?
Taking vitamin D could be helpful if you have psoriasis alongside your PsA. “Oral vitamin D supplementation may have some benefits in psoriasis,” says Dr. Bridges, though he notes that most research focuses on the efficacy of topical creams applied to plaques (versus oral supplements). “They work by slowing down the rapid skin cell turnover associated with psoriasis and have immunomodulatory effects.”
As for psoriatic arthritis, vitamin D may help ease symptoms—in theory. But “there are no studies that definitively show this, and much more work is needed,” says Dr. Bridges. “We also need studies to understand the role of vitamin D in the development and treatment of PsA, and the differences in vitamin D metabolism between patients with PsA compared to psoriasis without arthritis.”
What are the Best Sources of Vitamin D?
Sunlight is the primary source of vitamin D. “Vitamin D is made or synthesized in the skin from its precursor, a type of cholesterol,” says Shailendra Singh, M.D., a rheumatologist at White County Medical Center in Searcy, AK. “When you're exposed to the sunlight, that vitamin D precursor is formed in the skin—and once that is formed, that is converted into its active form in the liver and the kidneys.” But if you don’t spend a lot of time outside, then sunlight alone might not be enough to make the amount of vitamin D you need.
If that’s the case, you’ll need to get it from your diet—and, ideally, you should be eating your vitamin D rather than taking it through a supplement, according to Dr. Singh. “There are several foods which are enriched in vitamin D,” he says. “Most of the milk available in the market is enriched with vitamin D, as are yogurt and cheese.” You can also find vitamin D in fatty fish and fish liver oil.
How Much Vitamin D You Need With Psoriatic Arthritis
Besides infants, most people need 15 micrograms (mcg) of vitamin D a day, according to the National Institutes of Health (NIH). (A cup of milk has 2.9 mcg, while three ounces of salmon and trout each have over 14 mcg.) Even if you have psoriatic arthritis, that’s all our experts recommended. “I do not recommend routine vitamin D supplementation to treat psoriatic arthritis,” says Dr. Bridges.
The Risks of Too Much Vitamin D
Because it can increase calcium absorption, taking too much vitamin D can lead to hypercalcemia—literally, excessive calcium—which in turn leads to nausea, vomiting, and kidney stones. And while too much vitamin D alone can lead to kidney failure, it's extremely rare, according to the NIH. Really, it only tends to become a problem if you’re taking a lot of different vitamins, according to Dr. Singh. “Overdosing on vitamin D is very, very difficult,” he says.
And, even when you take it in an over-the-counter supplement, “that vitamin D needs to be activated inside the kidneys and in the liver to become active vitamin D—and our body will only produce as much active vitamin D as it needs,” he says. The rest gets excreted out.
Talk With Your Doctor
If you’re curious about supplementing with vitamin D, talk to your doctor—but manage your expectations accordingly. If your doctor checks your vitamin D levels and they’re low, they might recommend a supplement, says Dr. Singh. And if they’re normal, then supplementing with vitamin D won’t add any extra benefit for your psoriatic arthritis. And remember, it’s not a cure-all, and should at most be part of an overarching treatment plan overseen by your doctor.
https://www.healthcentral.com/condition/psoriatic-arthritis/psoriatic-arthritis-and-vitamin-d
