Flu Susceptibility and Anti-Inflammatory Fish Oil

Omega-3 Oils Reduce Inflammation, but May Increase H1N1 Infection Risk

The goal seems to be to reduce inflammation and reduce disease, but it isn’t that simple. Inflammation is not bad. Chronic inflammation is the problem for degenerative diseases. After all, inflammation is just what we call the mobilization of our immune system to fight infection. The problem is that inflammation needs to be properly controlled to be invoked only when needed, to be kept localized and to be brought to a proper conclusion.

A recent article extended studies of fish oil and various types of infections, to influenza. It used a mouse model that focused on the local, lung aspects of flu infection. Some mice were fed fish oil in a 4:1 ratio to corn oil (fish group) and the controls were just fed corn oil (corn group), as the lipid part of the diets.

Both fish oil and corn oil groups got sick when exposed to flu virus. The lungs of the fish treated group were less inflamed, but there was more virus and an increased death rate. The fish oil effectively reduced inflammation, but the inflammation in the corn oil, inflamed, mouse was useful in controlling the spread of the virus. Does this mean that chronic dietary inflammation is protective?

How close does this mouse system model human H1N1 infections? A lot can be learned from animal models, but not all aspects of the human disease are reflected in this model. There is no single H1N1 strain, for example. Flu viruses mutate thousands of times faster than even the most variable bacteria. Thus, people in various parts of Asia may be experiencing a different H1N1 than people in South America. Some H1N1 infections involve organs other than the lungs and cytokine storms can also be deadly.

If H1N1 is raging, is fish oil a good idea? It would be prudent to reduce other sources of inflammation, by eating an anti-inflammatory diet and getting plenty of exercise. The answer would seem to be to use only enough fish oil to reduce remaining symptoms of chronic inflammation, e.g. aching joints. The mouse model may have reduced the ability to produce an inflammatory response beyond elimination of chronic inflammation.

Most people who eat a high carb diet, with the typical inclusion of vegetable oils, starch and high fructose corn syrup would probably benefit from fish oil supplements, even in the context of influenza risk. It would take a lot of fish oil to compensate for the other inflammatory parts of their diet. Obesity is both a symptom of dietary inflammation and a source of chronic inflammation. Reluctance to engage in physical activity is another indicator of inflammation.

It would be helpful if epidemiologists studying the H1N1 swine flu pandemic would determine if chronic inflammation is a risk or benefit in surviving the disease. It would also be helpful to know what simple dietary or other interventions, e.g. nicotine, caffeine, would be helpful for various symptoms of the disease.

ref:
Schwerbrock NM, Karlsson EA, Shi Q, Sheridan PA, Beck MA. Fish Oil-Fed Mice Have Impaired Resistance to Influenza Infection. J Nutr. 2009 Jun 23. [Epub ahead of print]