Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (640 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Unctuous combustible substances that are liquid or easily liquefiable on warming, and are soluble in ether but insoluble in water. Such substances, depending on their origin, are classified as animal, mineral, or vegetable oils. Depending on their behavior on heating, they are volatile or fixed. (Dorland, 28th ed)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Where it fits in the MeSH classification
- Broader topics
- Lipids
- Narrower topics
- Fish Oils; Oils, Volatile; Plant Oils
Research landscape
PubMed indexes 110,606 records tagged with the MeSH heading “Oils” (counts retrieved 2026-10-31). 28,358 of them (25.6%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 38,185 records.
Reviews account for 10,403 records (9.4%) and meta-analyses for 1,038. Randomized controlled trials number 6,614 (6.0%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 23,891 |
| 2000-2009 | 20,172 |
| 2010-2019 | 38,185 |
| 2020 onward | 28,358 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 10,403 | 9.4% |
| Meta-analyses | 1,038 | 0.9% |
| Randomized controlled trials | 6,614 | 6.0% |
Method: PubMed query "Oils"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in drugs and chemicals
Studies of a chemical or drug can answer very different questions: what it is and how it behaves in cells and animals, how the body handles it, and whether it changes outcomes in people. Laboratory and animal findings often do not carry over to patients, and observational studies of exposures are confounded by who uses a substance and why. Nothing on this page is a recommendation to use, avoid, start or stop any substance or medicine; talk to a qualified clinician or pharmacist about your own situation. Check the dose, the species, the comparison group and whether a patient-relevant outcome was measured.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| CNS target engagement of high-dose DHA supplementation in older adults at risk for dementia: a randomised, double-blind, placebo-controlled trial | 2026 | Randomized controlled trial Design not recorded in structured metadata | 2 | cc by PMID 42315445 · DOI · PMC13347776 |
| Tubular Omega-3 Fatty Acid Receptor FFAR4 Deficiency Aggravated Renal Aging and Chronic Kidney Disease | 2026 | Research article Design not recorded in structured metadata | 2 | cc by PMID 42175992 · DOI · PMC13239551 |
| Feasibility, Safety and Preliminary Efficacy of 1:1 THC:CBD Cannabis Oil for Fibromyalgia Symptoms: Results From a Randomised, Double-Blind, Placebo-Controlled Pilot Trial | 2026 | Randomized controlled trial Design not recorded in structured metadata | 2 | cc by PMID 42142029 · DOI · PMC13179683 |
CNS target engagement of high-dose DHA supplementation in older adults at risk for dementia: a randomised, double-blind, placebo-controlled trial [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundAPOE ε4 carriers have increased Alzheimer's disease risk and altered omega-3 metabolism.
- Closing excerpt
- FundingNational Institute on Aging (R01AG057684) and the ADDF (GC-201711-2014197).
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (186 words)
BackgroundAPOE ε4 carriers have increased Alzheimer's disease risk and altered omega-3 metabolism. No large-scale prevention trials have tested high-dose docosahexaenoic acid (DHA) supplementation specifically in non-demented APOE ε4 carriers with low baseline omega-3 intake for early intervention.MethodsWe conducted a phase IIa 24-month, randomised, double-blind, placebo-controlled trial (NCT03613844) at the University of Southern California between September 2018 and May 2024. Participants aged 55-80 years without dementia, low dietary DHA intake (FindingsOf 739 screened individuals, 365 participants were randomised (181 LP arm, 184 no-LP arm). Mean age was 66.4 years (SD 5.7), 210 (58%) were female, 142 (39%) were Hispanic, 173 (47%) were APOE ε4 carriers. DHA supplementation increased CSF DHA/AA ratio at 6 months vs placebo (0.17 [95% CI 0.15-0.18] vs -0.02 [95% CI -0.04 to -0.0004]; difference 0.19 [95% CI 0.16-0.21]; p InterpretationHigh-dose DHA achieved CNS target engagement in non-demented older adults with low baseline omega-3 intake, independent of APOE ε4. Despite biochemical target engagement, no differences in cognition or brain structure were observed over 24 months. Future research should prioritise brain DHA metabolism over further supplementation trials.FundingNational Institute on Aging (R01AG057684) and the ADDF (GC-201711-2014197).
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42315445 · DOI · PMC13347776
Tubular Omega-3 Fatty Acid Receptor FFAR4 Deficiency Aggravated Renal Aging and Chronic Kidney Disease [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Aging leads to renal function decline and increases the risk of chronic kidney disease (CKD).
- Closing excerpt
- The study demonstrated a novel role of FFAR4 from senescent TECs on fibroblast activation via paracrine effects and highlighted the therapeutic effects of omega-3 PUFAs with their receptor FFAR4 as an attractive drug target against renal aging and CKD.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (197 words)
Aging leads to renal function decline and increases the risk of chronic kidney disease (CKD). Omega-3 polyunsaturated fatty acids (PUFAs) are essential fatty acids for humans, exerting their functions via free fatty acid receptor 4 (FFAR4). Clinical studies indicate that omega-3 PUFAs supplementation shows benefits for the elderly population and CKD patients, but these results remain controversial. Herein, we found that omega-3 PUFAs alleviated renal fibrosis and tubular senescence in aged mice, adenine diet-induced CKD mice, and unilateral ureteral obstruction (UUO) mice. Meanwhile, omega-3 fatty acid receptor FFAR4 expression in tubular epithelial cells (TECs) were down-regulated in the old population and CKD patients, positively correlated with renal dysfunction. Systemic or TEC-specific knockout of FFAR4 aggravated renal aging and CKD in mice. Mechanically, FFAR4 agonism increases the production of endogenous PPARγ activator 15-deoxy-∆12,14-Prostaglandin J2 (15d-PGJ2), and improves PPARγ-dependent tubular epithelial cell senescence, which was indicated by anti-aging marker Klotho expression, senescence-associated β-galactosidase (SA-β-gal) activity, and profibrotic factor TGF-β1 secretion. The study demonstrated a novel role of FFAR4 from senescent TECs on fibroblast activation via paracrine effects and highlighted the therapeutic effects of omega-3 PUFAs with their receptor FFAR4 as an attractive drug target against renal aging and CKD.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42175992 · DOI · PMC13239551
Feasibility, Safety and Preliminary Efficacy of 1:1 THC:CBD Cannabis Oil for Fibromyalgia Symptoms: Results From a Randomised, Double-Blind, Placebo-Controlled Pilot Trial [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Fibromyalgia is a chronic disorder characterised by widespread pain and other symptoms that substantially impact the quality of life.
- Closing excerpt
- Trial Registration: Australian New Zealand Clinical Trials Registry: ACTRN12623000345684.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (257 words)
Fibromyalgia is a chronic disorder characterised by widespread pain and other symptoms that substantially impact the quality of life. This double-blind, randomised, placebo-controlled trial primarily assessed feasibility (procedures and intervention adherence) and safety/tolerability of a 1:1 delta-9-tetrahydrocannabinol:cannabidiol (THC:CBD) cannabis oil (10 mg/mL each) in 24 adults with fibromyalgia, with secondary, preliminary assessment of efficacy across symptom domains. Participants completed a 4-week dose titration followed by 12 weeks of stable dosing. Of 77 prescreened individuals, 24 were randomised, yielding a screening-to-enrolment ratio of approximately 3:1 (31.2%). Recruitment reached 66.7% of the target (24/36); the shortfall was mainly due to geographic and legal barriers. Retention was 91.7% (22/24) and adherence was high, with all participants taking ≥ 90% of the prescribed doses. The study medication was well tolerated in this small sample, with adverse events mostly mild and no serious events observed. Secondary outcomes suggested medium to large between-group effects favouring cannabis for pain reduction, improved sleep quality, and reduced fibromyalgia impact (FIQR), but findings should be interpreted cautiously given the small sample. Clinically meaningful FIQR improvement (predefined MCID 45.5%) occurred in 40% of the cannabis-treated participants versus 10% with placebo. For pain, 70% of the cannabis group reported ≥ 30% reduction post-titration and at Week 12 (Placebo 20% and 40%, respectively). Fatigue and anxiety/depression showed no significant changes. A randomised trial of 1:1 THC:CBD oil appears feasible with excellent retention and adherence, though recruitment barriers need addressing. Preliminary safety and efficacy signals warrant confirmation in larger, adequately powered trials. Trial Registration: Australian New Zealand Clinical Trials Registry: ACTRN12623000345684.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42142029 · DOI · PMC13179683
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Efficacy of omega-3 PUFAs in depression: A meta-analysis [4]
- Research article Omega-3 fatty acid addition during pregnancy [5]
- Research article Marine Omega-3 Supplementation and Cardiovascular Disease: An Updated Meta-Analysis of 13 Randomized Controlled Trials Involving 127 477 Participants [6]
- Research article Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease [7]
- Research article Dietary n-3 PUFA, fish consumption and depression: A systematic review and meta-analysis of observational studies [8]
- Research article Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials [9]
References
- Yassine HN, Pour SG, Juarez M, Arrelanas IC, Ali N, Dikeman D, et al.. CNS target engagement of high-dose DHA supplementation in older adults at risk for dementia: a randomised, double-blind, placebo-controlled trial. . 2026. PMID 42315445 · DOI · PMC13347776
- Yang L, Tang L, Li J, Liu D, Hu C, Guo F, et al.. Tubular Omega-3 Fatty Acid Receptor FFAR4 Deficiency Aggravated Renal Aging and Chronic Kidney Disease. . 2026. PMID 42175992 · DOI · PMC13239551
- Kurlyandchik I, Tiralongo E, Lauche R, Tracey G, Ng J, Schloss J. Feasibility, Safety and Preliminary Efficacy of 1:1 THC:CBD Cannabis Oil for Fibromyalgia Symptoms: Results From a Randomised, Double-Blind, Placebo-Controlled Pilot Trial. . 2026. PMID 42142029 · DOI · PMC13179683
- Liao Y, Xie B, Zhang H, He Q, Guo L, Subramanieapillai M, et al.. Efficacy of omega-3 PUFAs in depression: A meta-analysis. Transl Psychiatry. 2019. PMID 31383846 · DOI · PMC6683166
- Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. Omega-3 fatty acid addition during pregnancy. Cochrane Database Syst Rev. 2018. PMID 30480773 · DOI · PMC6516961
- Hu Y, Hu FB, Manson JE. Marine Omega-3 Supplementation and Cardiovascular Disease: An Updated Meta-Analysis of 13 Randomized Controlled Trials Involving 127 477 Participants. J Am Heart Assoc. 2019. PMID 31567003 · DOI · PMC6806028
- Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, et al.. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2020. PMID 32114706 · DOI · PMC7049091
- Grosso G, Micek A, Marventano S, Castellano S, Mistretta A, Pajak A, et al.. Dietary n-3 PUFA, fish consumption and depression: A systematic review and meta-analysis of observational studies. J Affect Disord. 2016. PMID 27544316 · DOI
- Bernasconi AA, Wiest MM, Lavie CJ, Milani RV, Laukkanen JA. Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials. Mayo Clin Proc. 2021. PMID 32951855 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.