What is true is that the Omega 3 in flax seed oil is different from that in fish
oil, and
flax seed oil contains more than just omega 3 oils, whereas most
fish oil is artificially purified to eliminate many other beneficial oils that would also be a fish. Since you can get cold processed organically grown flax, whereas fish are contaminated pretty much everywhere now, and for vegetarians, flax is a good source of oil, but for a diabetic, fish oil probably would be a good choice.