Kidney Coach

Fish Oil & Omega 3 & Its Use In Kidney Disease

Fish oil and Kidney Disease

Omega-3 fatty acids are incredibly important and have numerous documented health benefits, they’re key to the structure of every cell wall you have and help your heart, lungs, blood vessels, brain and immune system work the way they should. But are they beneficial in kidney disease? Read on to find out.  

Omega-3s: What They Are 

Omega-3s are part of the family of polyunsaturated fatty acids (PUFAs). They are classified as essential fatty acids (EFAs), because they are essential for our health but can’t be made by the body. This means you must either get them from your diet or alternatively take them as a supplement.

There are three main omega-3 fatty acids:

  1.     Alpha-linolenic acid (ALA)
  2.     Eicosapentaenoic acid (EPA)
  3.     Docosahexaenoic acid (DHA)

ALA is found in plant oils while EPA and DHA are found in fish and other seafood. ALA can be converted into EPA and then to DHA but the conversion (which occurs mainly in the liver) is very limited (less than 15%). Therefore, consuming EPA and DHA directly from foods and/or supplements is the only practical way to increase levels of these fatty acids in the body.


Health Benefits of Omega-3 Fatty Acids

  • Can fight depression and anxiety
  • Can improve eye health- getting enough omega-3 is linked to a reduced risk of macular degeneration
  • Promote brain health during pregnancy and early life
  • Reduce the risk of cardiovascular disease
  • Can reduce symptoms of metabolic syndrome
  • Can fight inflammation
  • Can help prevent and treat autoimmune diseases
  • Can fight age-related mental decline and Alzheimer’s Disease
  • It May help prevent cancer
  • Can help prevent and treat Non-alcoholic fatty liver disease (NAFLD)

Fish oil and CKD

Today I specifically wanted to discuss the benefits and uses of fish oil supplementation in people with CKD. 

If there’s one thing that fish oil is best known for, it would be its anti-inflammatory actions, and this is where many of its benefits come from. Chronic inflammation is involved in the development and progression of most chronic diseases including heart disease, high blood pressure, diabetes, cancer, neurodegenerative diseases, autoimmune disease and of course kidney disease.

Inflammation and inflammatory reactions can change or interfere with blood flow both to and within the kidneys and can cause kidney damage which can enhance CKD progression. Systemic or intrarenal inflammation also contributes to the production of reactive oxygen species that contribute to damage of kidney tubules and nephron death.

Fish oils induce a series of chemical changes in the body that ultimately exert an anti-inflammatory action, they also suppress the production of inflammatory molecules and reduce the expression of genes that upregulate inflammation. Fish oil also increases the activity of two of our key antioxidant enzymes- Super Oxide Dismutase (SOD) and Glutathione Peroxidase (GPx) which means that as well as having anti-inflammatory actions, fish oil also helps to reduce oxidative damage within the body and the kidneys. 

Because of its anti-inflammatory effects, fish oil is particularly beneficial when kidney inflammation is present, in autoimmune kidney diseases and when kidney disease is caused by glomerulonephritis. 

Autoimmune Kidney Disease

Fish oil has been well studied in the management of autoimmune diseases, largely because of its anti-inflammatory properties. Inflammation is a key factor in all autoimmune conditions and contributes to the immune dysregulation at the centre of autoimmune disease. Chronic inflammation is a common symptom for people with autoimmune diseases and leads to damage that causes problems specific to each separate disease.

There are a number of studies looking at the use of fish oil in the management of IgA nephropathy. Supplementation with fish oil has been shown to reduce inflammation within the kidneys, significantly reduce proteinuria (protein loss in the urine), and haematuria (blood in urine), slow the progression of kidney disease and reduced the number of patients who developed end-stage renal disease (ESRD) when compared to placebo.

Some of the other benefits of fish oil in people with CKD

Reducing inflammation and the damage inflammation causes within the kidneys isn’t the only benefit of fish oil. Studies have also shown the following benefits:

Reduced proteinuria- Protein doesn’t generally pass into urine because protein molecules are too big to fit through the tiny filtering units of the kidneys. When the kidneys are damaged or not working properly, proteinuria can develop. The process of these large protein molecules getting through the tiny kidney filters causes further damage to the kidneys, increasing the progression of kidney disease. Reducing proteinuria can help to prevent further damage to the kidneys.

Reduced risk of vascular access graft thrombosis in patients on dialysis.

Improvement in uraemic pruritus- uraemic pruritus is chronic skin itching which is a common and distressing problem in the later stages of kidney disease.

Reduced erythropoietin (EPO) requirements- when you have kidney disease, your kidneys are less able to make EPO. Low EPO levels cause your red blood cell count to drop and anaemia to develop. EPO injections are often given to people in the later stages of kidney disease as a treatment of anaemia. Fish oil supplementation has been shown to reduce the frequency of EPO injections.

May increase albumin levels- albumin is the most abundant protein in the blood and its role is to keep fluid from leaking out of blood vessels, helps to repair tissues and carries hormones, vitamins, drugs and minerals throughout the body, Symptoms of low albumin include swelling in the face, hands or legs, fatigue, weakness, loss of appetite and nausea.

Improved bone density in osteoporosis.

Reduced blood pressure- high blood pressure is one of the primary causes of CKD and also contributes to the progression of kidney disease. Multiple studies have shown that fish oil can help lower blood pressure, by doing this it doesn’t just protect the kidneys from damage but also the rest of the blood vessels throughout the body. 

Benefits following kidney transplant- in a study involving patients after kidney transplant, fish oil had a beneficial effect on kidney blood flow and on blood pressure. Those in the fish oil group had significantly fewer rejection episodes than the control group and there was a trend to increased graft survival in the fish oil group.

Improves blood flow throughout the body including to the kidneys- any interruption or reduction in blood flow can cause kidney dysfunction or damage and if long-standing can also cause increased blood pressure.

Reduced risk of cardiovascular disease and sudden death.

That last point is so important that I wanted to discuss it in a bit more detail.

Benefits of Fish Oil for Cardiovascular Health

Fish oil in cardiovascular disease


People with CKD are at an increased risk of developing CVD and vice versa, in fact, people with CKD are more likely to die from CVD than they are from their kidney disease. For this reason, it’s super important to look after your cardiovascular health if you have kidney disease.

Fish oil has been shown to decrease the risk of cardiovascular disease, it reduces heart attacks, strokes, coronary artery disease, sudden cardiac death and may reduce total mortality by as much as 20-50%. 

Here are some of the ways fish oil reduces the risk of cardiovascular disease:

  • Improves cholesterol levels- specifically fish oil has been shown to lower triglycerides, very-low-density lipoproteins (VLDL) and total cholesterol and increase HDL (protective cholesterol). Not only that but fish oil reduces the oxidation of cholesterol which is the real problem child when it comes to cholesterol.
  • Reduce and possibly reverse atherosclerosis (‘hardening of the arteries’)- fish oil may also incorporate into atherosclerotic plaques making them more stable and less likely to rupture which reduces the risk of heart attacks and strokes.
  • Reduce inflammation and oxidative stress- inflammation and oxidative stress both contribute to the development and progression of CVD.
  • Reduces blood pressure
  • Improves endothelial function- the endothelium is a thin membrane that lines the inside of the heart and blood vessels. Endothelial cells release substances that control blood vessel relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet adhesion. Endothelial dysfunction precedes the development of atherosclerosis and has been shown to be of significance in predicting strokes and heart attacks. Endothelial dysfunction occurs in CKD and increases the risk for developing CVD.
  • Antithrombotic and Antiplatelet- fish oil can reduce the stickiness of blood and formation of blood clots which both reduces the formation of plaque in blood vessels and reduces the risk of heart attack and stroke. 
  • Improves blood flow throughout the body- fish oil helps to relax blood vessels, improving the delivery of blood and oxygen to the heart, the brain and throughout the rest of the body.

Supplementing with Fish Oil 

Fish oil is made from, surprise surprise- fish! This means it shouldn’t be taken by anyone allergic to fish and may not be appropriate for vegans or vegetarians. In these circumstances there is an alternative, algae oils are another source of omega-3s however they contain a lower dose than most fish oil supplements so people may need to take more of them to get an equivalent dose.

The other thing to be aware of is that like most supplements, not all fish oil supplements are created equal. Quality is super important when we’re talking about any herbal or nutritional supplement, but this is particularly the case when it comes to fish oil.  

Firstly, choose a fish oil that is thoroughly tested for environmental contaminants such as heavy metals and other toxins. Secondly, be aware of oxidised or rancid fish oil. 

Fresh fish oil has no fishy taste or smell, if it does, it has started to oxidize and go rancid. Rancid fish oil is likely toxic and has been shown to have a pro-inflammatory effect on the body. To work out whether your fish oil supplement is rancid, break open the capsule to taste and smell the oil inside, fresh, non-oxidised fish oil shouldn’t smell or taste fishy. You can also measure an oil’s rancidity level by looking at its oxidation values.  

Therapeutic Dose: 3gm to 8gm a day

To determine the appropriate dose of fish oil for you we do recommend discussing this with your naturopath or doctor and we don’t recommend taking high doses of fish oil unless under supervision by a healthcare provider. 


Because of fish oil’s antiplatelet actions, there is a theoretical concern that it may increase the risk of bleeding if used alongside anticoagulant or antiplatelet drugs. While there have been some individual case reports of increased bleeding in people taking fish oil alongside warfarin, multiple larger studies have been conducted where fish oil has been administered alongside warfarin and other anticoagulant or antiplatelet medications which do not reflect this risk. 

Despite the lack of evidence of a safety concern, it still pays to be mindful of this theoretical risk if taking fish oil alongside blood thinning medication and to continue to monitor INR if taking fish oil alongside warfarin.

Summing it all up

So, to sum things up:

  1. We need omega-3 fatty acids for our body to function properly
  2. Fish oil has important anti-inflammatory actions
  3. Fish oil has a variety of benefits when it comes to kidney disease but is particularly useful in autoimmune kidney disease and when kidney inflammation is present
  4. Fish oil is important in the prevention and treatment of CVD which is more common in people with CKD

Hopefully, you’ve found this overview of fish oil useful. If you have, I’d love you to let me know by clicking the ‘SHARE’ button below or leaving a comment on our Facebook page

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