SUPPLEMENTS UPDATE
The fish oil dose the trials actually used, and the turmeric cases that changed my advice
A follow-up to the May supplements deep dive, with the trial that defines a real fish oil dose and the liver signal that moved turmeric up my question list.
Week of August 14, 2026. Angelo Papachristos PT, ACPAC. RheumAcademy | Arthros Inc.
In early rheumatoid arthritis, fish oil at 5.5 grams a day of EPA plus DHA, added to standard triple therapy, roughly doubled the rate of remission and cut failures of triple therapy to about a quarter of the control rate. That is the Proudman trial, published in the Annals of the Rheumatic Diseases in 2015, and it is the strongest evidence any supplement has in inflammatory arthritis. It is also a dose almost nobody taking fish oil gets anywhere near.
Back in May I went through the whole supplement bag, from vitamin D to collagen powder, and that piece still stands (the May deep dive is here). This one goes narrower. Two questions kept coming back in clinic after it ran: what would fish oil look like if I took it properly, and is turmeric dangerous or just useless. Both have concrete answers, and the vitamin D file needs two additions from the same trial that produced the good news.
The fish oil trial worth knowing in detail
The design first. Proudman and colleagues took patients with rheumatoid arthritis of under twelve months' duration, none of whom had started disease-modifying therapy, and put everyone on triple therapy: methotrexate, sulfasalazine and hydroxychloroquine, adjusted to a treat-to-target algorithm. On top of that, patients were randomised two to one to fish oil delivering 5.5 grams a day of combined EPA and DHA, or a low control dose of 0.4 grams for masking.
The high-dose group failed triple therapy at roughly a quarter of the control rate and reached formal remission about twice as often. Side effects were no different, and average disease activity scores looked similar between the groups, so read this as a real shift at the remission end rather than a transformation for everyone. It is a treatment-course benefit. No trial has shown fish oil protecting joints on imaging, and nothing in this study touched the disease-modifying drugs themselves; every patient stayed on them.
Now the arithmetic, because this is where the supplement aisle quietly defeats the evidence. A typical 1000 mg drugstore capsule carries around 300 mg of combined EPA and DHA. The older positive trials clustered around 2.7 to 3 grams a day, which works out to nine or ten of those capsules, and Proudman used 5.5 grams. If you want to trial it, buy a product listing at least 600 to 800 mg of EPA plus DHA per capsule and read that line specifically, because the front of the bottle counts oil, and the trials counted EPA and DHA.
Timing matters as much as dose. The meta-analysis behind the symptom claims, Goldberg and Katz in the journal Pain in 2007, pooled seventeen randomised trials and found reductions in patient-reported joint pain, morning stiffness and NSAID use after three to four months of supplementation. Give it a full three months at a real dose before judging it. And park the heart claims: in the VITAL trial, the omega-3 arm did not reduce major cardiovascular events overall, so if fish oil earns a place, it earns it for your joints.
Vitamin D: the two null results I owed you
The May piece covered the interesting part. In VITAL, vitamin D supplementation lowered the rate of new autoimmune diagnoses by about 22 percent over five years of follow-up, a prevention finding in older adults who did not yet have autoimmune disease (Hahn, BMJ, 2022). Nothing since has turned that into a treatment for established lupus or rheumatoid arthritis, and the trials that tried have been disappointing.
What I did not give you in May were the parent trial's main results. VITAL randomised 25,871 adults to 2000 IU of vitamin D daily or placebo. It did not reduce cancer or major cardiovascular events (Manson, New England Journal of Medicine, 2019), and a later analysis found no reduction in fractures in adults who were not selected for deficiency or osteoporosis (LeBoff, New England Journal of Medicine, 2022). Correcting a low level is worthwhile. Pushing a normal level higher adds nothing, and sustained mega-dosing in the 10,000 IU a day range brings real risk, hypercalcemia and kidney stones included.
The unambiguous territory has not moved either. If you are on prednisone for three months or longer, vitamin D and calcium remain standard background alongside whatever bone-targeted treatment your fracture risk calls for, per the 2017 American College of Rheumatology guideline on glucocorticoid-induced osteoporosis. Ask for a serum 25-hydroxyvitamin D level, correct a deficiency into the normal range, and stop there.
Turmeric: from vague concern to named cases
In May I filed turmeric under small trials and mixed quality. The harm side has firmed up enough to deserve better than a passing line. The US Drug-Induced Liver Injury Network published ten adjudicated cases of turmeric-associated liver injury (Halegoua-DeMarzio, American Journal of Medicine, 2023): six enrolled since 2017, mostly a hepatocellular injury pattern, five patients hospitalised, and one death from acute liver failure. Chemical testing confirmed turmeric in all seven products tested, and three also contained piperine, the black pepper extract added to improve absorption.
Turmeric in food is fine and always was. The concern sits with concentrated high-dose extracts, and it lands hardest if you are on methotrexate or another drug we monitor with liver blood tests, because an unlabelled second cause of liver injury makes that monitoring harder to read. This is now a supplement I ask about by name.
The interaction short list, with names
St John's wort stays at the top. It induces the liver enzyme CYP3A4 and can quietly drop blood levels of cyclosporine, tacrolimus, some JAK inhibitors and oral contraceptives far enough to matter. If you take it for mood while on any of those, tell your prescriber; that combination needs to come apart. High-dose fish oil has a mild blood-thinning effect, so raise it with your pharmacist if you are on warfarin or apixaban, and mention it before any planned surgery or procedure.
What to do, and the conversation to have
Bring the actual bottles, or clear photos of the labels with the doses visible, to your next appointment, including anything you take inconsistently. If you are on prednisone, have darker skin and live through a Canadian winter, or spend most of your time indoors, ask for a serum 25-hydroxyvitamin D level rather than guessing; if it comes back low, correct it into the normal range and hold there. If you want to trial fish oil for joint symptoms, buy a product listing at least 600 to 800 mg of EPA plus DHA per capsule, run it for three months at a studied dose, and then decide with your team whether it earned the shelf space. Stop St John's wort if you are on cyclosporine, tacrolimus or a JAK inhibitor, and name any concentrated turmeric product out loud, especially if your liver is being monitored. A pharmacist-led medication review covers all of this in one sitting; ask for one.
Questions for your care team
- Can we check my vitamin D level rather than assume it, and is my current dose set for correction or for maintenance?
- Against my prescription list, which of my supplements should stop, starting with St John's wort and concentrated turmeric?
- If I trial fish oil, what daily EPA plus DHA dose should I aim for, and when do we judge whether it worked?
- Should any of my blood monitoring change while I am taking these?
What this does not mean
Nothing here touches the treatment that changes the course of your disease. The fish oil benefit in Proudman happened on top of full triple therapy, in patients who stayed on their disease-modifying drugs throughout. Vitamin D corrects a deficiency and protects bone on steroids; it does not treat established lupus or rheumatoid arthritis. If a supplement plan involves stopping a prescribed drug, that is the moment to call your rheumatology team, before anything gets stopped.
References
Proudman 2015 - fish oil in early rheumatoid arthritis. Proudman SM, et al. Fish oil in recent onset rheumatoid arthritis: a randomised, double-blind controlled trial within algorithm-based drug use. Ann Rheum Dis, 2015. https://pubmed.ncbi.nlm.nih.gov/24081439/
Goldberg 2007 - omega-3 meta-analysis for inflammatory joint pain. Goldberg RJ, Katz J. A meta-analysis of the analgesic effects of omega-3 polyunsaturated fatty acid supplementation for inflammatory joint pain. Pain, 2007. https://pubmed.ncbi.nlm.nih.gov/17335973/
Manson 2019 - VITAL vitamin D primary results. Manson JE, et al. Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease. N Engl J Med, 2019. https://pubmed.ncbi.nlm.nih.gov/30415629/
Manson 2019 - VITAL omega-3 primary results. Manson JE, et al. Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer. N Engl J Med, 2019. https://pubmed.ncbi.nlm.nih.gov/30415637/
LeBoff 2022 - VITAL vitamin D and fractures. LeBoff MS, et al. Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults. N Engl J Med, 2022. https://pubmed.ncbi.nlm.nih.gov/35939577/
Hahn 2022 - VITAL vitamin D and incident autoimmune disease. Hahn J, et al. Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial. BMJ, 2022. https://pubmed.ncbi.nlm.nih.gov/35082139/
Halegoua-DeMarzio 2023 - turmeric-associated liver injury. Halegoua-DeMarzio D, et al. Liver Injury Associated with Turmeric: A Growing Problem. Ten Cases from the Drug-Induced Liver Injury Network (DILIN). Am J Med, 2023. https://pubmed.ncbi.nlm.nih.gov/36252717/
Buckley 2017 - ACR glucocorticoid-induced osteoporosis guideline. Buckley L, et al. 2017 American College of Rheumatology Guideline for the Prevention and Treatment of Glucocorticoid-Induced Osteoporosis. Arthritis Rheumatol, 2017. https://pubmed.ncbi.nlm.nih.gov/28585373/
This article is for education and is not a substitute for individual medical advice. Supplements, doses, and interactions depend on your specific diagnosis, medications, and blood work. Talk to your own rheumatology team and pharmacist before starting, stopping, or changing anything.
Angelo Papachristos PT, ACPAC. Advanced Practice Physiotherapist. Co-Founder, RheumAcademy. Co-Founder, Arthros Inc.