I would take the claims made in this article with a big grain of salt.
There is no attempt to give the actual papers, volume, year etc from Diabetes Care. The only one I did find was a Dr Petersen gave vitamin D to obese teenagers who were Vitamin D deficient and noted a lowering of their insulin resistance.
The 20 year old paper about fish is presumable there somewhere but given how inaccurately the vitamin D paper seems to have been read I have my doubts.
Huckleberries apparently grow in North America and someone in Perth Australia cultivates them. They look like a large blueberry with a tart taste. There are used in cooking and as a traditional medicine. Who knows where the claim about use in diabetes comes from ???
Cumin, tested by which British scientists, in which journals and how well regarded are these bods?
And who says cheese and peanut butter 'rev' insulin sensitivity ?
I think all the magazine wishes to achieve is increased sales by publishing bunkum for the masses.