Sorry it has taken awhile to answer the questions about Brewers
yeast/chromium and insulinoma treatment.  I had a computer problem, but
I am back up and running again.
 
Seems like there are 3 basic questions:
1) is chromium good to give to insulinoma ferrets(no),
2) is chromium safe to give to healthy ferrets(yes), and
3) can chromium possibly prevent insulinomas in healthy ferrets(maybe).
 
I will try to clear up some of the general information first, then answer
those 3 questions.  Brewers yeast is a common ingredient in pet foods
because it provides some of the B vitamins (esp. Thiamine B-1) and
chromium.  Thiamine is a very important B vitamin that is needed by
ferrets and most mammals.  Chromium is the part that causes the confusion.
 
1) Chromium is NOT a good thing to give an insulinoma ferret because it
actually lowers blood glucose levels.  Chromium also has some insulin like
properties.  Clearly we do not want to lower an insulinomas already low
blood glucose level.  Nor do we want to give something that acts like
insulin when there is already to much insulin being produced by the
insulinoma.  Chromium is a good thing to give to diabetic people and pets,
but diabetes is rare in ferrets.
 
2) Yes chromium is safe to give to ferrets without insulinomas.  Again
brewers yeast has a lot of the needed B vitamin thiamine.  Chromium does
not cause problems in the healthy ferret.
 
3) Can chromium prevent insulinomas?  This is a good question that needs
further research.  Since chromium helps to lower the post meal glucose
surge, it may help to prevent stimulation of the pancreas that occurs after
eating a meal with carbohydrates in it.  It is this overstimulation of the
pancreas after eating carbohydrates (sugary treats, rice, etc.) that cause
an insulinoma to form.  If we had a ferret diet with a low carbohydrate
level (10%) instead of the 20-30% carbohydrate diets that we currently
have, If we had a diet with carbohydrates that produced lower post meal
glucose peaks (sorghum, corn, barley) instead of rice that produces the
highest post meal glucose peak, If we had a diet with enough chromium to
lower the post meal glucose peak, then we might prevent insulinomas from
occurring in ferrets.  Again this is an area that needs further research.
Based on what we currently know, chromium is a good thing for healthy
ferrets, but a bad thing for ferrets with an insulinoma.
 
Hope that clears up the confusion,
Jerry Murray, DVM
[Posted in FML issue 3446]