Chromium polynicotinate has been involved in helping to maintain the amount of glucose in the body to constant and control blood sugar levels and diabetes. It help to lose weight and reducing cholesterol levels in the body by role to increase HDL as well.
This is straight from my IFA personal trainer reference book: chromium helps to lower blood sugar, reduce body fat and cholesterol levels. It is also used to suppress appetite. In diabetic and overweight individuals, chromium reduces triglyceride levels by almost 20%, improves glucose tolerance and normalizes insulin levels. Deficiencies can result in insulin resistance. Typical dosage is 50-200 mcg daily. An ounce of brewers yeast provides aprox 100-200 mcg of chromium.
HEALTH HAZARDS: in picolinate form, may cause DNA damage, which can result in genetic mutation and cancer. Possible anemia, blood abnormalities, liver dysfunction and renal failure.
So in closing, chromium is beneficial through brewers yeast but hazardous while in picolinate form.