Are supplements necessary?

[Stovo]

I'm diving down the nutritional rabbit hole and it appears pretty much all vitamins & minerals can easily be obtained from diet, other than Vitamin D in winter. 

For reference I eat a balanced diet primarily of 7-8 portions of fruit & Veg per day, lots of fish, lots of meat, some milk, oats, rice, sweet potatoes, but I avoid wheat as gluten doesn't match well with me, no seed oils. Only exceptions are when I eat out it isn't always possible to stay this strict. 

I remember seeing one of Leo's videos years ago when he had all these food supplements, can this be healthy if I can just get them from my diet?