Chemotherapy May Be Impeded With Taking Fish Oils

There has been much debate over the effectiveness of chemotherapy treatments when coupled with the supplementation of fish oils.

Many chemotherapy patient’s first reaction to starting the treatment is to immediately switch to a healthy diet and begin taking a variety of food supplements in order to help keep their body as healthy as possible during their therapy.

In this article, we will delve deeper into this reasoning and reveal whether fish oils impede chemotherapy or not.

Chemotherapeutic Treatment

Chemotherapeutic drugs are designed to target rapidly dividing cancer cells and prevent them from replicating. Their main mission is to eliminate these cells and reduce the presence of any tumours in the patient’s body.

Benefits of Fish Oils:

Over the past years, fish oils have become an increasingly popular food supplement. Omega-3 is one of the most popular forms of fish oil due to its wide range of benefits that it gives when taken as a daily supplement.

It has been cited to provide many benefits when taken in normal circumstances. Some benefits include:

  • Lower blood pressure
  • Reduced buildup of plaque in the arteries
  • Decreases chance of cardiovascular issues such as strokes and heart attacks
  • May help with mental disorders
  • Aid weight loss
  • Supports eye health

There are many reported advantages to adding fish oil supplements to a healthy and balanced diet. However, several recent studies indicate that some forms of chemotherapy treatment may be adversely affected by fish oils being present in the diet.

Let’s dive deeper into the complications.

Possible Complications When Taken During Chemotherapy Treatment:

Some complications that have been observed during the research are as follows:

Increases in Plasma Levels in Fatty Acid

It has been reported that one of the main complications that fish oils present is increases in the plasma levels of the fatty acid.

The research, which was carried out by JAMA Oncology, found that the increased plasma levels of the fatty acid created chemoresistance in the mice it was tested on. This does not bode well for chemotherapy patients, specifically those who are suffering from tumours.

The fish oil is known to contain compounds that can reduce the anti-tumour properties of the chemotherapy treatment. This is a direct contradiction to what the treatment is trying to achieve.

Changing of Treatment Dosage

Another observed complication is how fish oil can unintentionally change the dose of chemotherapeutic drugs.

The fish oils can change how the drug is absorbed in the gastrointestinal system of the patient and alter the way the body receives the chemotherapy, making it more difficult for the doctors to regulate dosages.

Altering of Cell Membranes

The fish oil supplement can also affect the membrane of the fatty cells to make them ‘stiffer’ and more resilient to the chemotherapy.

This makes it harder for the treatment to penetrate these cells, which makes it more difficult for the treatment to travel around the body. This can reduce the effectiveness of chemotherapy.


From recent studies it seems that it would be wise for chemotherapy patients to avoid taking fish oils if possible.

Some researchers have warned patients against eating certain types of fish, such as herring and mackerel, because of their high concentration of the damaging fish oils. However, other fish such as salmon and tuna have been deemed safe for consumption.

These findings are not only restricted to fish oils. Recent studies have found that several other food supplements can affect chemotherapy treatment too.

Some other supplements that researchers have found to have adverse effects on chemotherapy treatment include; green tea, St. John’s wort, valerian root and garlic extract.

The best advice is to consult your doctor before taking any OTC (over the counter) supplements whilst on chemotherapy.