

Saturday, September 5, 2009

A fish a day keeps the doctor away

Is it true that there can be too much of a good thing? In the case of inflammation, the answer is certainly YES. Inflammation can be seen as the familiar red puffiness around a healing wound or the unseen swelling of an injured organ. Inflammation is the result of the immune system responding to dangerous pathogens, such as bacteria or parasites. Without it, our bodies would fail to heal wounds and fight off infections. When inflammation goes unchecked, however, serious tissue damage can result. Imagine a scraped knee. A little soap and water can do a lot to prevent infection, while non-stop scrubbing of the wound will eventually do more harm than good. Inflammation is a similar scenario, only at the molecular level. Artherosclerosis, rheumatoid arthritis, fibromyalgia, shoulder tendinitis, inflammatory bowel disease, to name just a few, are all associated with inflammation.

The human immune system is a compilation of cells that circulate around the body to recognize, attack, and eliminate foreign invaders. The lining of cells, known as the membrane, contains fats and proteins that regulate immune system activity. During microorganism invasion, these fats and proteins in the membrane help the immune system soldiers navigate through our organs towards the microscopic enemy. The immediate immune response to foreign matter is known as acute inflammation. To prevent unwanted chronic inflammation, different proteins in the cell’s membrane will stop the immune system from continued combat.

To date, quite a few groups have reported an association between dietary omega-3 fatty acids and decreased inflammatory related diseases. From these studies, omega-3 fatty acids were given the all-important name “anti-inflamatory” agents. This is turn prompted many health agencies and doctors to recommend increased intake of omega-3 fatty acids. No one actually understood, however, why omega-3 fatty acids prevented inflammation (Am I the only one who finds blind recommendations a little scary?)! How many pills and supplements do you take without understanding what they do in your body? Sadly, those who recommended them in the first place might not understand either.

Not to worry, Samantha P. Tull from the University of Birmingham in the United Kingdom recently reported a possible link between EPA, the type of omega-3 fatty acid found in fish, and anti-inflammation. Tull’s team studied endothelial cells, the type of cell that lines the inside of blood vessels and the very layer that separates the immune system from our organs. Additionally, Tull examined the neutrophil, a front-line soldier activated in an immune system response.

Tull’s group exposed endothelial cells to EPA and found that membranes readily incorporated the new fatty acid. Upon close observation, Tull found that endothelial cells that were not exposed to EPA allowed neutrophil passage through the cell layer, while EPA-treated endothelial cells opposed neutrophil passage. Additional experiments showed that EPA acts in the membrane to block proteins that are used to help neutrophils migrate through the endothelial cells.

Tull’s data supports the idea that omega-3 fatty acids serve as anti-inflamatory agents. One might hypothesize that this essential nutrient treats inflammatory-related diseases by stopping neutrophil migration from the blood stream into inflamed tissues. Without migration of neutrophils through blood vessels into organs, the inflammation process cannot be sustained and eventually subsides.

Although Tull’s study is convincing, her experiments were performed in a petri dish. To validate her interpretation of the data, a look at the effect of omega-3 fatty acids in a mammalian model, such as mouse or rat, is warranted. Regardless, it is quite satisfying to have a potential explanation as to why omega-3 fatty acids are anti-inflammatory.

The bottom Line: EPA, a type of omega-3 fatty acid found in fish, potentially acts as an anti-inflammatory agent by stopping excess migration of cells from the immune system into our organs. Perhaps I’ll have fish for dinner tonight!

Reference: Tull SP, Yates CM, Maskrey BH, O'Donnell VB, Madden J, et al. 2009 Omega-3 Fatty Acids and Inflammation: Novel Interactions Reveal a New Step in Neutrophil Recruitment. PLoS Biol 7(8): e1000177. doi:10.1371/journal.pbio.1000177

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