Fat improves vitamin D absorption
Vitamin D is fat-soluble and absorbs better with dietary fat. Taking with omega-3 fish oil provides the fat needed for optimal vitamin D uptake.
Take vitamin D with omega-3 or fatty meal.
Take together with food
Fat improves vitamin D absorption. Take vitamin D with omega-3 or fatty meal.
Take together with food
This interaction is rated “Synergy” by Formulate. Vitamin D is fat-soluble and absorbs better with dietary fat. Taking with omega-3 fish oil provides the fat needed for optimal vitamin D uptake.
Studies from our registry that mention omega-3 or vitamin d. Each links to the primary source and the other Formulate pages citing it.
Mentions vitamin d · 2022
The D-Health Trial: a randomised controlled trial of the effect of vitamin D on mortality
Neale et al. · The Lancet Diabetes & Endocrinology
D-HEALTH trial (n=21,315). Monthly 60,000 IU vitamin D did not reduce all-cause mortality over 5 years.
Mentions omega-3 · 2020
Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events (STRENGTH)
Nicholls et al. · JAMA
STRENGTH trial (n=13,078). High-dose EPA/DHA did not reduce cardiovascular events — contradicts REDUCE-IT finding.
Mentions omega-3 · 2019
Omega-3 Fatty Acids for the Management of Hypertriglyceridemia: A Science Advisory From the American Heart Association
Skulas-Ray et al. · Circulation
AHA science advisory on triglyceride-lowering effects of 2–4g/day EPA+DHA — typically a 20–30% reduction.
Mentions vitamin d · 2019
Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease
Manson et al. · New England Journal of Medicine
VITAL trial (n=25,871). 2,000 IU/day D3 did not significantly reduce cancer incidence or cardiovascular events in a generally replete population.
Mentions omega-3 · 2019
Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia (REDUCE-IT)
Bhatt DL, Steg PG, Miller M, et al. · New England Journal of Medicine
Double-blind RCT (n=8,179) found high-dose EPA (4g/day) reduced ischemic events by 25% vs placebo in patients with elevated triglycerides on statins — the most convincing cardiovascular benefit data for omega-3s.
Mentions omega-3 · 2019
Efficacy of omega-3 PUFAs in depression: a meta-analysis
Liao et al. · Translational Psychiatry
EPA-dominant formulas (≥60% EPA) were significantly more effective for depression than DHA-dominant ones.
Roundup
Best Omega-3 Supplements 2026, Ranked by Clinical Evidence
Learn to decode EPA+DHA labels, absorption forms, and oxidation scores. We ranked 8 omega-3 supplements using clinical evidence — no guesswork.
Roundup
Best Vitamin D Supplements 2026: Ranked by Clinical Evidence
42% of adults are deficient. Learn which D3 form, dose, and brand actually raises blood levels — with cofactor guidance and lab-verified picks.
Review
Vitamin D3 vs D2: The Science Behind the 87% Gap
D3 raises blood levels 87% more effectively than D2 — and your prescription vitamin D might be the inferior form. Here's what to know.
Other interactions to know
Fish oil may increase bleeding risk with warfarin
Fish oil adds to aspirin's antiplatelet effect
Vitamin D and K2 work synergistically
Vitamin D enhances calcium absorption
Fat improves curcumin absorption
Magnesium needed for vitamin D activation
Boron extends vitamin D half-life
Vitamin E protects omega-3 fats from oxidation
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Medical disclaimer. This page is for educational purposes only and does not replace advice from a qualified healthcare provider.
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