Omega-3 Oils Keep the Swelling Down

DHA and EPA help with inflammation

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Inflammation occurs with many chronic and acute diseases. Fish oil, a source of omega-3 fatty acids, may help curb this painful symptom.

A recent review of studies looking at the effects of omega-3 fatty acids has shown that including them into treatment plans can be beneficial.

The trials showed benefits for both healthy people and for those suffering from conditions like heart disease, kidney failure and sepsis.

"Ask your doctor about omega-3 supplements."

This review was authored by Oscar D. Rangel-Huerta, a researcher with the Department of Biochemistry and Molecular Biology Molecular, Institute of Nutrition and Food Technology and Jose Mataix Biomedical Research Centre at the University of Granada in Spain.

The review examined 26 clinical trial studies by Asian, European, Canadian, Australian and American researchers on the effects of two types of fish oil omega-3 fatty acids: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Rangel-Huerta and his colleagues found that DHA and EPA have the ability to reduce markers for inflammation across a wide range of people.

Inflammation is a necessary process that the body goes through when presented with harmful stimuli. This stimulus causes the body to make chemicals called eicosanoids, which control the inflammatory process. Examples of these chemicals include prostaglandins, prostacyclins and thromboxanes.

Cells in the body incorporate omega fatty acids into their cell walls. When inflammation is triggered, enzymes turn these fatty acids into eicosanoids. Different fatty acids produce eicosanoids and omega-3 fatty acids make a specific series of eicosanoids called series 3 eicosanoids, which cause significantly less inflammatory effects than the more common series 2 eicosanoids.

Rangel-Huerta found more trials regarding fish oil and cardiovascular disease to include in the review than any other disease. Though there was some debate on the ideal dosage, fish oil proved to have positive effects in six out of the eight clinical trials dealing with cardiovascular disease.

Sepsis, commonly known as a blood infection, is inflammation resulting from a systemic infection that is most often bacterial. Many of the most detrimental symptoms are cause by inflammation. The review authors included 3 studies showing that intravenous parenteral administration of EPA and DHA lessened the damage of the septic inflammatory response and strengthened the immune response to the infection.

Two studies in the review covered renal disease and both found fish oil improved inflammation marker levels compared to placebo. Fish oils also benefit renal disease patients by reducing certain cardiovascular disease risks.

Two studies on the effects of fish oil on Alzheimer’s patients found opposed results. The first study found that fish oil helped reduce inflammatory immune responses and the second study found no effects. This was probably due the dosage, which was roughly three times less DHA and EPA than the first study.

Rangel-Huerta and his colleagues found ten trials that studied the inflammatory response effects of fish oil on healthy users. A majority of the studies on healthy subjects found that fish oil had no effect on inflammatory marker levels compared to placebo.

However, three of the ten studies on healthy subjects found reductions in the patient’s inflammatory biomarker compounds.

A greater dose of the omega-3 was associated with better anti-inflammatory results, both for one test on healthy subjects and for the successful trial on Alzheimer’s. Both of these trials used higher dosages and had more success.

Only two of the studies in this review had more than 100 subjects, so these studies suffer in general from low participation. Understanding of proper dosage levels is also a problem with research into omega-3 fish oil that will have to be addressed with further research.

Because of the positive effects fish oil can provide for many disease conditions, Rangel-Huerta and his colleagues encourage both the use of this supplement and further research that focuses on the different effects of different doses.

The available evidence indicates that there are at least some benefits in healthy people supplementing with fish oil, though a person should always consult a doctor before taking a new supplement.

There were no mentions of any adverse events or side effects resulting from the fish oil. Even though it was fairly safe during the trials, users of fish oil should never exceed maximum dosage because fish oil can cause vitamin A toxicity.

This review of clinical trials was published in the June issue of BMJ. Funding was partially provided by the Instituto de Salud Carlos III, which is a part of the Spanish Ministerio de Ciencia e Innovación.

Reviewed by: 
Review Date: 
July 9, 2012
Last Updated:
October 1, 2012