I saw some public TV shows while in the US by a chap called Dr Perricone. He's a dermatologist and big advocate for a diet rich in fish oil and fish. His programs were very interesting. For example he advocates wild salmon over farmed as it has higher levels of omega-3 (most tinned salmon is wild). The main thrust seemed to be that most/all disease involves inflammation and so eating things which reduced inflammation is a good thing. Being a dermatologist, there was a lot of stuff about dealing with skin related issues (aging/acne/blemishes/...).
He has several books out and a diet (excellent way to make money). Haven't read them but did skim through one, similar content but more detailed:
Perricone Prescription