Fighting Flu with Fish Oil

Fish oil is traditionally considered as a treatment option in inflammatory conditions such as pain, arthritis, cardiovascular disease, depression and mood disorders. However, it does have some scope for inclusion in treatment plans for cold and flu season.

“DHA-enriched fish oil can enhance B cell activation and select antibody production.”

A study published in the Journal of Leukocyte Biology suggested that consumption of DHA-rich fish oil may boost immune function by enhancing the function of immune B cells.[1]

Fish oil derived docosahexaenoic acid (DHA) is generally believed to suppress T lymphocyte function, however the effect of fish oil on B cell function had been relatively unexplored. Given the important role of B cells in immunity, researchers tested the hypothesis that DHA is incorporated into the cell membrane to alter lipid microdomain clustering and enhance B cell function.

The discovery was significant as it showed that fish oil does not necessarily reduce the overall immune response to lower inflammation, but may actually have immune enhancing properties that could benefit immunocompromised individuals.[2]

Study details

Investigating their theory, the science team used two groups of mice fed either a control diet or a diet supplemented with DHA-rich fish oil for five weeks. B cells were then harvested from several tissues and stimulated in culture. It was found that DHA-enriched fish oil enhanced B cell activation and select antibody production, which was suggested to aid immune responses associated with pathogen clearance while possibly dampening the totality of the inflammatory response.

“These results support the hypothesis and an emerging concept that fish oil enhances B cell function in vivo,” confirmed the researchers.

Antiviral effects

Meanwhile, Japanese scientists discovered an ability for protectin D1 (PD1), a compound derived from omega-3 polyunsaturated fatty acids, to treat influenza infection in mice.[3] Importantly, PD1 was found to be beneficial even at advanced stages of infection, during which existing antivirals were no longer effective.

“Given the potential for future lethal pandemics, effective drugs are needed for the treatment of severe influenza, such as thosse caused by H5N1 viruses,” said senior study author Yumiko Imai in a press release via EurekAlert.[4] “We’ve identified a novel therapeutic target for the treatment of severe influenza that is effective under conditions where known antiviral drugs fail to protect from death.”

In their study, Imai and collaborators found that PD1 was effective at inhibiting the replication of viruses, and furthermore, low levels of PD1 in the lungs of influenza-affected test animals was associated with severe infection and highly pathogenic viruses such as H5N1. More interestingly treatment with PD1 improved the survival and pathology of severe influenza in the animals.

“Our findings suggest that PD1 could serve as a biomarker as well as a much needed antiviral drug for severe and lethal influenza virus infections,” Imai stated.

These results identify the omega-3 derived lipid mediator PD1 as an innate suppressor of influenza virus replication that may protect against lethal influenza infection.


  1. Gurzell EA, Teague H, Harria M, et al. DHA-enriched fish oil targets B cell lipid microdomains and ex vivo and in vivo B cell function. J Leukoc Biol 2013;93(4):463-470. [Full Text]
  2. Science news. Nothing fishy about it: fish oil can boost the immune system. ScienceDaily, 1 Apr 2013. [Link]
  3. Morita M, Kuba K, Ichikawa A, et al. The lipid mediator protectin D1 inhibits influenza virus replication and improves severe influenza. Cell 2013;153(1):112-125. [Full Text]
  4. O’Leary MB. Fatty acids could lead to flu drug. EurekAlert! Public release date, 7 Mar 2013. [Link]


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