The others are right - it is the high starch, high sugar diets that are a trigger for laminitis. Many, many years ago it was suspected that high protein was the trigger (because feeds such as spring grass and cereals were both high starch/sugar and high protein) but it has now been proved not to be the case. Read any up to date information on laminitis and it will tell you this.
Soaked hay and straw is good, but I would only give a Laminitis Trust approved chaff such as Happy Hoof or Hi Fi Lite, as some chaffs are highly mollassed and therefore high in sugar. Personally, I would cut out the bran unless that has been specifically recommended by the vet, as I suspect that bran has a higher starch content than would be safe for a potential laminitic.
She's just had her first injection. Now i need to monitor her closely for any sighns of lami. The vet said to check her twice a day but i think it will be a few more times than that!