>The fact that foods such as sardines - which are rich in taurine, omega 3, calcium and vitamin D - have a clear protective effect against the onset of diabetes does not mean that taking these supplements in isolation will have the same effect.

The only way i can understand this statement it that Rizzolo doubts that anything in the sardines are actually affecting type 2 diabetes. So perhaps the oily taste is suppressing apatite for 'sweet' and decreasing the patients sugar intake (decreasing them cheating on their diet).

Anyway a 152 patients study is not very conclusive, in larger studies there may not be any effect there at all.