Vitamin D, inflammation and rheumatoid arthritis: what’s the link?

Should I take vitamin D if I have rheumatoid arthritis? Does vitamin D aggravate or cause inflammation in the body in general?

Physiotherapist, I answer these questions based on the studies published on the subject!

♻️ Last update: 5 October 2024.
👩‍⚖️ Declaration of financial interests: none directly related to the subject. My complete declaration of interest is in the legal notice section.
Written by Nelly Darbois, physiotherapist and scientific editor

What kind of inflammation are we talking about here?

Inflammation is the name given to our body’s natural response to aggression, infection, injury or irritation. It is there to protect and repair damaged tissues.

Inflammation is generally a short-term reaction, although it can sometimes become chronic.

In this article, I’m going to focus on a very specific type of chronic inflammation: that occurring in people with rheumatoid arthritis.

But I also deal more generally with chronic inflammation, because I know that many Fonto Media readers are interested in it!

Common causes of inflammation

Here are the most common causes of inflammation.

Acute (lasting up to 3 months):

1. Bacterial, viral or fungalinfections . For example, sinusitis.
2. Injuries: cuts, sprains, operations, etc. Like inflammation after a knee replacement.
3. Allergic reactions.
4. Chemical irritants: such as inhalation of toxic gases.

Chronic (lasting more than 3 months or even “for life”):

1. Autoimmune diseases: such as rheumatoid arthritis, lupus and multiple sclerosis.
2. Inflammatory bowel diseases (IBD): such as Crohn’s disease and ulcerative colitis.
3. Atherosclerosis: accumulation of plaque in the arteries.
4. Obesity: associated with chronic inflammation.
5. Cancer: cancer cells can release inflammatory signals, contributing to chronic inflammation.

Why focus on the link between vitamin D, inflammation and rheumatoid arthritis?

I became interested for 2 reasons:

• a few people around me (patients or family members) have already asked me questions about whether or not I should take vitamin D for rheumatoid arthritis;
• I’ve noticed that since the 2010s, there have been dozens of studies on the subject every year. And that there’s no website offering a complete but accessible overview.

Hence this article, which I hope is clear!

Here are these famous studies:

What do studies say about inflammation, rheumatoid arthritis and vitamin D?

To produce this article, I went to see what the best-quality studies on the subject had to say.

And I’m transcribing here what’s interesting for Mr. and Mrs. Everyman 🙂.

Studies on rheumatoid arthritis and vitamin D

Here’s what one of the main summaries of recent studies on the subject has to say:

Vitamin D deficiency, combined with genetic and environmental factors, can lead to the onset of rheumatoid arthritis.

Research into the potential role of VD supplementation in the treatment of RA has produced conflicting results; further large-scale pharmacological research is needed to determine the effects of increasing vitamin D during the treatment of polyarthritis.

Aslam 2019

In simpler terms:

• In some people, vitamin D deficiency is one of the triggers of rheumatoid arthritis ;
• It’snot yet known whether taking vitamin D supplements can relieve the symptoms of rheumatoid arthritis or slow down the disease.

Current research is trying to identify which people with rheumatoid arthritis might benefit from taking vitamin D: those with low vitamin D levels?

Studies on other chronic inflammations and vitamin D

The effect of vitamin D on chronic inflammation is mainly studied for polyarthritis.

There is even more uncertainty about the effects of vitamin D in other types of chronic inflammation. For example, in cases of chronic inflammatory bowel disease or diabetes.

On the other hand :

[in people with diabetes and covid-19] a strong rationale exists for the therapeutic administration of additional vitamin D to reduce COVID-19-related respiratory complications or to prevent, in the event of infection, a severe form of COVID-19.

Argano 2022

Source: Garcia 2020, Argano 2022

Should you take vitamin D for rheumatoid arthritis?

When I explain the results of these studies to people with rheumatoid arthritis , here’s what they decide.

Some decide not to pay particular attention to their vitamin D intake and sun exposure, since there is no evidence of vitamin D’s effect on polyarthritis.

They also tell themselves that taking too much vitamin D can have deleterious effects (nausea, vomiting, constipation, muscle weakness, loss of appetite and confusion).

They therefore prefer not to take vitamin D supplements or change their diet.

Others tell themselves that “a little extra vitamin D can’t hurt”. They tell themselves that if one day we learn that vitamin D is good for rheumatoid arthritis , they’ll be glad they took it.

In studies evaluating the effect of vitamin D on polyarthritis, the amounts given are often large: often at least 50,000 IU per week, or even much more and more often (Cochrane 2015).

Studies suggest that it’s better to take vitamin D regularly rather than one or 2 boluses a year, as this would limit the risk of side effects (Harrison 2019). Especially in elderly people at risk of falls.

What is the best position to adopt?

I don’t think I can go any further than presenting you with this information. It’s now up to you to make your choice based on this information, for yourself, according to what you like best!

Personally, I think that if vitamin D intake significantly improved polyarthritis, we’d already have data on this. Because it has already been tested on thousands of people, and studies tend to overestimate efficacy rather than underestimate?

Should I take vitamin D for inflammation in general?

My current knowledge leads me to believe not.

But as with polyarthritis, some people will take a different stance and decide to take it, based on the same study data.

I hope this article has provided you with a few pointers to help you make your own decision!