Medically reviewed by Lindsay Cook, PharmD
Why this matters: Taking omega-3 and vitamin D together may improve absorption and offer added health benefits.
What you can do: Ask your doctor whether taking omega-3 and vitamin D together is right for you.
The payoff: Combining these supplements may support healthy aging, brain function, and stronger bones.
Omega-3 and vitamin D are both popular supplements, but they may offer additional benefits when taken together. Because vitamin D is fat-soluble, taking it with omega-3 fatty acids may improve its absorption. Research has explored how combining these supplements could benefit health, though the evidence is mixed.
1. It Might Slow Biological Aging
The supplement combo may help lower your biological age, which reflects your health status, compared to your chronological age.
Studies show that taking about 1 gram of omega-3 per day may slow down biological aging by up to four months. A 2025 study found that daily vitamin D supplementation of about 2,000 international units (IU) per day can reduce biological aging, with or without omega-3 fatty acids.
However, researchers have found that taking omega-3 and vitamin D together has even greater benefits for biological aging.
2. Mood Disorders May Improve
Vitamin D helps reduce inflammation in the brain and may help enhance cognition and mood. Omega-3 also supports brain function and can help boost cognition. In addition, omega-3’s inflammation-reducing properties may stabilize the nervous system and improve mood.
Taking both vitamin D and omega-3 supplements together may improve depression and anxiety. Both supplements work together to ease depression by reducing inflammation and balancing brain chemicals.
However, if you live with depression or anxiety, talk to your healthcare provider, as supplements do not help treat the underlying causes of depression.
3. Your Heart Health May Improve
Vitamin D can reduce the risk of heart attack in patients with heart disease. Omega-3 helps lower triglyceride levels and reduce platelets from sticking together, which can help keep you healthy and protect your heart against stroke.
There are mixed results on the heart health benefits of taking both supplements together. Some studies suggest taking both vitamin D and omega-3 together may help reduce the risk of health disease-related deaths in patients with heart attack, stroke, or heart failure. Other studies have not found a significant benefit of taking both supplements together in preventing heart disease.
4. Your Bones Might Get Stronger
Omega-3 fatty acids may help enhance bone formation and prevent bone from breaking down. Vitamin D helps your body absorb calcium, which can help you maintain strong bones.
Both omega-3 and vitamin D may help reduce the risk of osteoporosis. Taking vitamin D and omega-3 fatty acids together may help enhance bone health and reduce fractures.
5. Your Blood Sugar May Go Down
Some research has shown that taking omega-3 fatty acids and vitamin D together can help lower blood sugar levels. A 2021 study found that taking vitamin D and omega-3 fatty acids for about six weeks effectively reduced blood sugar in women with gestational diabetes, a type of diabetes in pregnancy.
Who Should Avoid Taking Omega-3 and Vitamin D Together?
Combining omega-3 fatty acids and vitamin D is generally safe when used at recommended doses. However, this supplement combination may not be best for everyone, especially people living with certain conditions or taking certain medicines.
Talk to a healthcare provider first if you:
Have severe fish or shellfish allergies, as many omega-3 supplements are made with fish oil
Have kidney or liver disease
Take medications that increase your risk of bleeding (e.g., warfarin), as omega-3 can increase your bleeding risk
Take medications like statins (atorvastatin or simvastatin) and thiazide diuretics (Hygroton and Microzide)
Are pregnant or breastfeeding
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