That linked article goes in to way too much depth to really paste anything useful here but he basically says that while there are short term benefits to fish oil, it could actually be quite harmful to take it in the long term.
In one issue they could say that drinking a beer a day in moderation can prevent certain cancers and taking too much health supplements can cause irreversible, long-term damage to your liver. Then six issues later they could say to get the dream abs you've always wanted, you must take these same health supplements every day and cut out all beer.
They can provide facts and statistics to sell you any nutritional scare story, and the whole game is this: they want you to think that you NEED them, so that you will continue to buy their magazine. Most people take one story or more from this type of scare tactic and run with it. Every diet has its secret. Every nutritionist has his angle to keep you living for longer or to get results in the gym faster. No wants makes money on the obvious: eat equally from every food group and without bias, exercise regularly (cardiovascular and weight training) and most importantly - have a bit of luck on the way - and you'll be fine.
Still, from what I read, effects show up only long-term. I might get impotent because of these plastic altering stuff, which makes plastic softer (ie bottles) but this stuff leaks into the fluid/food - alter genes, increase cancer risk, and act like estrogen.
For example he says that fish oil has toxic effects on the liver and cites Ritskes-Hoitinga, et al., 1998. The actual paper says that fish oil may have hepatoxic effects in herbivorous animals and that therefor when using herbivorous animals to study the effects of fish oil on atherogenesis, the effects on these animals livers may need to be excluded (because it's not observed in other animals).
I was particularly intrigued by his discussion of how different fats impair or are required for mitochondrial functioning, but I barely understood it.