Is Fish Oil Good for Your Liver and Kidneys?

October 16, 2025 •

4 min read

Chronic kidney disease affects more than 10% of the global population, while non-alcoholic fatty liver disease (NAFLD) impacts about 25% of adults in the U.S.. With such high prevalence, many people question if fish oil is good for your liver and kidneys, and research shows promising results in supporting these organs due to its anti-inflammatory properties and role in fat metabolism.

Quick Summary

This article examines the evidence supporting the benefits of fish oil's omega-3 fatty acids for liver and kidney health, focusing on inflammation reduction, fat metabolism, and potential risks, highlighting dietary sources versus supplements.

Key Points

Supports Liver Health: Omega-3s reduce liver fat and inflammation associated with non-alcoholic fatty liver disease (NAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD) by influencing fat metabolism and reducing pro-inflammatory molecules.
May Protect Kidneys: Observational studies link higher intake of marine omega-3s with a lower risk of chronic kidney disease (CKD) and a slower decline in kidney function.
Beneficial for Specific Conditions: Fish oil supplementation has been shown to slow kidney disease progression in patients with IgA nephropathy and may benefit dialysis patients by improving some lab markers.
Anti-Inflammatory Effects: The EPA and DHA in fish oil are potent anti-inflammatory agents, which can benefit both organs by reducing chronic inflammation and oxidative stress.
Potential for Risks: Taking certain amounts of fish oil may increase the risk of bleeding. Individuals with existing liver disease or on blood-thinning medication should be particularly cautious.
Source Matters: Research suggests that omega-3s from seafood sources (EPA and DHA) are more effective for kidney health outcomes than plant-derived ALA.
Consult a Doctor: It is essential to speak with a healthcare provider before beginning fish oil supplementation, especially for those with pre-existing conditions affecting the liver or kidneys.

The Role of Fish Oil's Omega-3s

Fish oil is rich in omega-3 polyunsaturated fatty acids (PUFAs), primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are essential for various bodily functions and are known for their potent anti-inflammatory effects. While the typical Western diet contains an unbalanced ratio of omega-6 to omega-3 fatty acids, increasing the intake of marine omega-3s is a strategic way to address this imbalance. The potential health benefits of omega-3s, and therefore fish oil, are attributed to their ability to modulate metabolic processes and reduce systemic inflammation.

Fish Oil and Liver Health

Targeting Non-Alcoholic Fatty Liver Disease (NAFLD)

NAFLD, now often referred to as metabolic dysfunction-associated steatotic liver disease (MASLD), is a condition marked by excess fat accumulation in the liver. A key mechanism by which fish oil can benefit the liver is through its ability to improve lipid metabolism. Omega-3s inhibit the genes involved in fatty acid synthesis and storage while promoting those that increase fatty acid oxidation. This helps to prevent or reduce the buildup of fat in liver cells.

Combating Liver Inflammation and Oxidative Stress

Chronic inflammation is a significant contributor to liver diseases, including the more severe non-alcoholic steatohepatitis (NASH). EPA and DHA in fish oil can help lower the production of pro-inflammatory cytokines, reducing the overall inflammatory load on the liver. This anti-inflammatory action also helps mitigate oxidative stress, which further protects liver cells from damage. A meta-analysis published in Frontiers in Nutrition found that fish oil supplementation improved triglycerides and aspartate transaminase (AST) levels in patients with MASLD.

Fish Oil and Kidney Health

Potential Benefits in Chronic Kidney Disease (CKD)

Observational studies have associated higher levels of seafood-derived omega-3 fatty acids with a lower risk of developing chronic kidney disease (CKD). The anti-inflammatory and vascular benefits of omega-3s are thought to be particularly protective for kidney function over time. However, randomized controlled trials are still needed to establish a definitive cause-and-effect relationship and understand appropriate use for the general CKD population.

Supporting Transplant Patients and Specific Conditions

For specific kidney conditions, fish oil has shown more targeted promise. For example, in patients with IgA nephropathy, a condition causing kidney inflammation, dietary fish oil has been shown to slow the decline of kidney function. Additionally, some studies have shown that fish oil may be beneficial for kidney transplant recipients who take calcineurin inhibitor-based immunosuppressive drugs, which can be toxic to the kidneys. A small study from June 2025 found that omega-3 supplementation improved BUN and creatinine levels in hemodialysis patients, although longer and larger studies are needed.

Potential Risks and Considerations

While fish oil offers potential benefits, there are important considerations, especially for individuals with pre-existing liver or kidney conditions. Some studies suggest that certain amounts of fish oil might increase the risk of bleeding, particularly for those on blood-thinning medications or with existing liver scarring. Cod liver oil, unlike standard fish oil, contains high levels of vitamin A and D, and excessive intake could lead to liver toxicity.


Feature	Effect on Liver	Effect on Kidneys
Anti-Inflammatory Action	Reduces inflammation in NAFLD/MASLD.	Protects against inflammation-induced damage.
Fat Metabolism	Decreases liver fat accumulation.	Indirectly supports kidneys by managing associated metabolic conditions.
Cardiovascular Support	Improves cholesterol and triglyceride levels, reducing strain.	Lowers blood pressure, a key factor in CKD progression.
Detoxification	Enhances liver function by improving cell membrane integrity.	No direct impact, but healthy liver function supports overall organ health.
Potential Risks	May increase bleeding risk in those with liver scarring with certain amounts.	Some amounts may increase bleeding risk; effects in some advanced diseases still unclear.

Conclusion

Based on current research, fish oil, particularly its omega-3 fatty acids, presents a compelling case for supporting liver health, primarily by reducing liver fat and inflammation associated with NAFLD. For kidney health, the evidence is supportive but warrants careful consideration, especially for specific conditions like IgA nephropathy and patients on dialysis, where some benefits have been observed. The general population may see indirect benefits through cardiovascular improvements and inflammation reduction. However, it is crucial to consult a healthcare provider before starting any fish oil supplementation, especially for those with pre-existing conditions, to ensure appropriate use and avoid potential side effects like increased bleeding risk. A balanced diet rich in omega-3s from food sources remains a safe and effective strategy for promoting overall health.

Recommended Sources of Omega-3s

Fatty Fish: Salmon, mackerel, sardines, and herring are excellent sources of EPA and DHA.
Plant-Based Options: Flaxseeds, chia seeds, and walnuts provide ALA, which the body can partially convert to EPA and DHA.
Algal Oil: For vegetarians and vegans, this supplement provides a direct source of EPA and DHA.

Healthy Lifestyle Practices for Organ Support

Maintain a healthy weight and BMI.
Engage in regular physical activity.
Control blood pressure and blood sugar levels.
Limit alcohol consumption.
Ensure a diet rich in fruits, vegetables, and whole grains.
Consider supplementation only under medical supervision.

Frequently Asked Questions

Fish oil cannot reverse advanced fatty liver disease (NAFLD/MASLD) on its own, but research indicates that the omega-3s in fish oil can help reduce liver fat accumulation and inflammation, particularly when combined with diet and lifestyle changes.

While general population studies show a link between marine omega-3s and lower CKD risk, results for existing CKD patients are mixed. Some specific conditions like IgA nephropathy and hemodialysis may see benefits, but large, long-term studies are still needed.

There is no universally typical amount for liver and kidney support. For general health, a common amount of combined EPA and DHA is sometimes noted. Therapeutic amounts can be higher, but should only be determined by a healthcare provider due to potential risks.

Yes, fish oil can interact with certain medications. Certain amounts may increase the risk of bleeding, especially for those on blood thinners. It can also potentially interfere with blood pressure or blood sugar control in some individuals.

Within typical use, fish oil is generally considered safe. Higher amounts can increase bleeding risk, particularly with pre-existing liver scarring. Excessive intake of specific liver oils (like cod liver oil) can lead to vitamin A toxicity and liver damage.

Incorporating whole food sources like fatty fish is generally considered a good way to get omega-3s and other nutrients. Supplements can be an option for those who don't eat enough fish, but quality varies. Purified supplements may help reduce contamination risks.

Omega-3s, specifically EPA and DHA, reduce inflammation by lowering the body's production of pro-inflammatory substances like cytokines and inflammatory eicosanoids, while increasing anti-inflammatory compounds.