Mangoes contain high levels of water, so they are considered a high volume of fruit.  As a high volume fruit, they provide a large volume of food for a relatively low calory count. 
 
Mangoes are known for having:
 
Potassium
Vitamin A
Betacarotene
Vitamin C
Calcium
Phosphorus
Magnesium 
A rich source on enzymes (ideal for tenderizing and marinades)