Kitten with heart murmur

Question
I placed a kitten with a loving family and have just learned that kitty was diagnosed with a heart murmur, rated as "1".  It was so faint that it wasn't discovered until kitty's 5th vet visit.  He is now 5 months old and has no other health issues and has never been ill although I did treat him with clavamox a couple months ago as a precentative measure.  Another kitten showed signs of a developing cold so I took the litter to vet and chose to treat them all, just in case.  

One thing I have read is that foods can sometimes cause or clear up murmurs.  Kitty was on a high quality natural food (petguard)  and I believe his new family changed his food right away.

Any insight?  Thank you so much.

Answer
There are many people and kitties with mild heart murmurs that are of no significance.

In cats, the most common reason for symptomatic heart murmurs is cardiomyopathy.  One type of cardiomyopathy (dilated) will respond to foods high in an amino acid called taurine, which is added to most commercial cat foods.  The other type of cardiomyopathy (hypertrophic) is a genetic problem and will not respond to changes in the food.