I recently learned that Cod Liver Oil has too much Vitamin A, so we switched to Carlson's Fish Oil. But is even that a bad idea? Is fish oil immunosuppressive only if it's CLO with Vitamin A? Is it immunosuppressive only if you take too much? Or should fish oil not be used at all? I could definitely benefit from a stronger immune system!
The main rationale for fish oil being immunosuppressive isn't about fish oil per se, it's about omega-3 being anti-inflammatory. Chronic inflammation is, of course, very bad indeed, but acute inflammation is integral to the immune system. There must be some reason why we evolved inflammatory responses and it presumably wasn't so our bodies could kill us!
To confuse everything, I switched out fish oil for fermented CLO. I figured the Vitamin D would help boost my immune system. Sure enough, I haven't gotten sick this cold season. I don't plan on sticking with the CLO after it warms up though.
At low doses, this isn't a big problem. In my opinion, the risk of chronic inflammatory disease (heart disease, stroke, cancer, neurodegenerative diseases, autoimmune diseases) outweighs the risk of infection. You can limit the fish oil to a gram or so per day and if you are able to drastically restrict your n-6 PUFAs. Remember inflammation and immunity are two sides to the same coin. The result makes perfect sense.
Whether something is beneficial (usually anti-inflammatory) or harmful (usually immunosuppressive) depends on the person, the situation and the dosage of the agent in question. I said "usually" because sometimes immunosuppression is good, eg. after an organ transplant. I don't believe the "dose-response curve" of fish oil has been accurately worked out. I believe that fish oil supplements are beneficial at some lowish dose if you don't eat much fish, and that the risks/harms outweigh the benefits at some higher dose. Dr. Harris recommends 1 to 2 tsp. of CLO per day if you don't eat fish, and you're eating supermarket meat ( http://www.paleonu.com/get-started/ ). This is about 1 to 2 grams of O3 PUFAs per day.