You shouldn't need to supplement if you eat a decent diet and have no underlying condition. Of course if you do have a condition or have an illness then taking supplements can help. Or, if you're an athlete or sportsman that regularly depletes his/her body's reserves owing to recovery, then yes, supplements have their place.
However, they are "supplements", i.e. they supplement a diet not replace it. I'd address your diet/food first. Getting your "5 a day" (which is unnecessary in my research and view but that's another discussion) is easy, eating oily fish and getting omega 3 is easy - you just have to want to do it. If you don't, then of course take supps, but wouldn't you rather just have a healthy lifestyle without them?
Remember a lot of "research" is funded by companies wanting to sell you these items too. Remember also I did say there is a place for supps, but just don't go using them just because. In the small doses these things come in they may not affect you adversely, but my concerns are that so many people are shunning a good diet over eating rubbish and using supplements. It's a daft way to do it.