Olive oil has to be one of the best and most versatile things going.Seem to remember reading about it as good for being anti inflammatory mainly
And here's one of hundreds of links.
We actually use olive rather than cod liver oil- basically because we live in olive producing region and you see the old boys and girls here having a real degree of mobility despite having had really hard lives. Another anecdotal issue is that I've seen chronic arthritis sufferers seemingly benefit from a mediterranean diet rich in olive oil whilst living over here. Like I say it seems to work for Old Harry.