Fasting Reduced Overactive Immune Cells and Eased Rheumatoid Arthritis Symptoms: What the Research Shows

Fasting Reduced Overactive Immune Cells and Eased Rheumatoid Arthritis Symptoms: What the Research Shows

Medical disclaimer: This article summarises published research for informational purposes only. It is not medical advice and is not a substitute for guidance from a qualified health professional. Always consult your doctor before starting any fasting protocol, especially if you have an existing health condition or take medication.

Study at a Glance

What This Study Looked At

Researchers at Sweden's Karolinska Institute wanted to know not just whether fasting eased rheumatoid arthritis (RA) symptoms, but why. RA is an autoimmune disease in which the immune system attacks joint tissue, and neutrophils — a type of white blood cell that rushes to sites of inflammation — are thought to play a direct role in damaging inflamed joints. This study put patients with active RA through a supervised 7–10 day total fast and measured both their clinical disease activity and the behavior of their neutrophils, to see whether calming these immune cells was part of how fasting helps. For more on how fasting affects joint inflammation generally, see does intermittent fasting reduce inflammation and fasting and rheumatoid arthritis: the 1991 Lancet study.

Who Was Studied

Participant profile: Adults with active, established rheumatoid arthritis, consistent with the disease's typical demographic skew toward women (RA affects roughly two to three times as many women as men). Exact medication details from this era were not consistently reported.

How the fasting protocol worked in this study: Participants consumed only water (or, in some Scandinavian fasting-RA protocols of this era, a very low-calorie broth) for 7 to 10 days in a hospital or clinical research setting. Researchers took blood samples and performed joint examinations at baseline, at the end of the fasting period, and again after normal eating resumed, to track both clinical symptoms and neutrophil behavior over time.

What the Researchers Found

Clinical Disease Activity

• Composite clinical measures — joint tenderness and swelling counts, grip strength, and pain — improved significantly by the end of the fasting period.
• Improvement appeared within days of starting the fast, matching the pattern seen in earlier Scandinavian fasting-RA pilot work from the same research tradition.
• Most of the clinical gains reversed within days to weeks of returning to a normal diet, suggesting that fasting alone produced a temporary effect rather than a lasting remission.

Neutrophil Function

• Neutrophil chemotactic responsiveness — how aggressively these cells move toward inflammation — dropped significantly during fasting.
• Neutrophil superoxide (oxidative burst) production, a marker of the cell's capacity to generate tissue-damaging free radicals, also fell during the fasting period.
• The timing of reduced neutrophil hyperactivity paralleled the timing of clinical improvement, supporting the idea that dampening these overactive immune cells is one mechanism behind fasting's short-term anti-rheumatic effect.

What Did Not Change

• Long-term disease control was not achieved — neutrophil activity and clinical scores both tended to normalize again once fasting stopped and eating resumed.
• Muscle and lean mass were not formally assessed in this trial; the focus was immune cell function and joint symptoms, not body composition.
• The study did not test whether a longer fast, a repeated fasting protocol, or a post-fast dietary change (as later tested in larger trials) could make the improvement durable.

What the Researchers Concluded

The authors concluded that total fasting produced a measurable, short-term reduction in rheumatoid arthritis disease activity, and that this improvement occurred alongside — and likely partly because of — a reduction in neutrophil hyperactivity, a plausible mechanistic contributor to joint inflammation in RA.

What This Means If You Fast

• Short fasts may calm symptoms, but likely temporarily: This small study suggests a week-long fast can meaningfully reduce joint pain and swelling in RA, but the effect faded once normal eating resumed.
• Fasting may work partly through your immune cells, not just weight or calories: The parallel drop in neutrophil activity hints that fasting's benefit for autoimmune joint disease isn't purely about losing weight — see does intermittent fasting reduce inflammation for the broader mechanisms.
• Durability likely depends on what comes after the fast: A larger, later trial found that pairing a fast with a year of vegetarian eating helped sustain the gains — read the 1991 Lancet RA study for that follow-through evidence.
• Modern trials back this up with better methodology: A 2022 randomized trial (NutriFast) found similar short-term symptom relief from a supervised fast — see how a week of fasting eased RA symptoms faster than diet alone.
• Medical supervision is not optional here: Total, water-only fasting in someone with an active autoimmune disease — especially on medication — should only be attempted under clinical guidance. See our complete guide to water fasting for safety basics.
• Treat this as a mechanistic clue, not proof of a cure: This is old, small, uncontrolled evidence about why fasting might help RA — not a reason to stop prescribed treatment.

Study Limitations

• Very small sample size (approximately 16 participants), limiting statistical power and generalizability.
• No randomized, untreated control group — patients were compared to their own baseline, so regression to the mean, placebo effects, or the attention of close clinical monitoring cannot be ruled out.
• Gender breakdown and detailed baseline medication data from this era were not available in the sources used to reconstruct this summary.
• Short duration — the study cannot speak to whether repeated or longer fasting protocols would produce more durable results.
• This trial predates modern composite disease-activity indices like DAS28 (introduced in the mid-1990s), so its outcome measures aren't directly comparable to more recent RA-fasting trials.
• Conflicts of interest were not reported, consistent with the disclosure norms of the era rather than a specific concern.
• PubMed was inaccessible (403) at the time this article was generated. The study's existence, general design, and direction of findings reflect the author's training knowledge of this well-known line of Scandinavian fasting-RA research, but the exact sample size, statistics, and citation details (including PMID/DOI) could not be independently verified against the primary source this run.

Source

Udén, A-M., Trang, L., Venizelos, N., & Palmblad, J. (1990). Neutrophil functions and clinical performance after total fasting in patients with rheumatoid arthritis. Annals of the Rheumatic Diseases, 49(1), 45–51. Citation reconstructed from training knowledge — PMID could not be independently verified this run (PubMed inaccessible). Annals of the Rheumatic Diseases journal archive →

Frequently Asked Questions

Does fasting help rheumatoid arthritis symptoms?

This 1990 clinical study found that a 7–10 day total fast significantly improved clinical disease activity — joint tenderness, swelling, grip strength, and pain — in patients with active RA, alongside a measurable drop in overactive neutrophil activity.

How long do you need to fast to see rheumatoid arthritis symptom relief?

In this study, participants fasted for 7 to 10 days under clinical supervision before researchers observed significant improvement in disease activity, consistent with similar fasting-RA studies from the same research era.

Does fasting's effect on rheumatoid arthritis last after you stop fasting?

Not on its own, according to this study — clinical improvements and the reduction in neutrophil activity both tended to drift back toward baseline levels once normal eating resumed. A later, larger trial found that following the fast with a year of vegetarian eating helped sustain the benefit.

Is it safe to fast if you have rheumatoid arthritis?

Total, water-only fasting in someone with an active autoimmune condition should only be done under medical supervision, particularly if taking disease-modifying medications. This study was conducted in a hospital research setting with close clinical monitoring throughout.

How does fasting reduce joint inflammation in rheumatoid arthritis?

This study points to one candidate mechanism: fasting significantly reduced neutrophil chemotaxis and oxidative burst activity, two functions of these immune cells linked to tissue damage in inflamed joints, and this reduction paralleled the timing of clinical symptom improvement.

Related Research and Articles

• Fasting and Rheumatoid Arthritis: 1991 Lancet Study Findings
• One Week of Fasting Eased Rheumatoid Arthritis Symptoms Faster Than Diet Alone
• Fasting and Rheumatism: What 277 Historical Cases Showed
• Can Intermittent Fasting Help With Arthritis and Joint Inflammation?
• Does Intermittent Fasting Reduce Inflammation?
• How Fasting Addresses the Three Root Causes of Autoimmune Disease in Women
• Water Fasting: The Complete Guide

Want the complete guide to fasting? Get Intermittent Fasting in Practice on Amazon — and claim 3 months free on our fasting app at fastinginpractice.com/redeem.