Vitamin D helps keep the bones and muscles healthy. Omega-3 fatty acids support a healthy heart and improve the function of the immune system. Combining the supplements may help reduce inflammation and manage certain health conditions.
Some studies suggest that vitamin D supplements may help reduce cancer pain and muscle pain, especially in people with low vitamin D levels. Omega-3 has been found to stop pain from worsening.
Taking vitamin D and omega-3 together can help prevent and manage chronic pain due to their inflammation-lowering effects. A 2022 study found that taking both supplements together reduced pain more effectively than taking either one alone.
However, not all studies support the use of omega-3 fatty acids and vitamin D for pain reduction. A 2020 study observed that U.S. adults with chronic knee pain who took both omega-3 and vitamin D for more than five years did not see any significant decrease in pain.
Studies show that taking about 1 gram of omega-3 per day may slow down biological aging by up to four months. However, researchers have found that taking omega-3 and vitamin D together has even greater benefits for biological aging. Biological aging reflects the state of your organs and tissues and can predict your risk of diseases like Alzheimer’s and stroke.
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.
If you are considering taking supplements for this purpose, consider talking to your healthcare provider. Taking omega-3 or vitamin D might be more beneficial than taking both, especially if you have an underlying condition.
Vitamin D helps reduce inflammation in the brain and may help enhance cognition and mood. Omega-3 is also a brain food 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 cause of depression.
Studies suggest that vitamin D can significantly improve sleep quality, especially in older adults and pregnant people. Omega-3 has also been found to improve sleep quality.
A 2021 study found that taking magnesium and omega-3 together helped improve sleep quality in women. However, there is not enough evidence to recommend taking omega-3 and vitamin D together to improve sleep quality. If you are concerned about your sleep quality, talk to your healthcare provider about supplement recommendations and other possible solutions.
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.
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 (weak and brittle bones).
Taking vitamin D and omega-3 fatty acids together may help enhance bone health and reduce fractures.
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). However, omega-3 is not recommended in pregnancy without first talking to your healthcare provider.
Combining omega-3 fatty acids and vitamin D is likely 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.
Do not take omega-3 and vitamin D without talking to your healthcare provider 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
