We learned that breast milk is a hot bed for bacteria. 

Researchers in Spain have tracked the bacterial make-up of human breast milk and found that it has over 700 species of bacteria. 

But before you buy formula for your child, researchers say these colonies of bacteria are crucial to a baby’s health.   The bacteria in a mother’s breast milk help the infant develop normal flora (good bacteria) in his or her own body and that builds up the immune system.

Interestingly, the heavier the mother is, the fewer species of bacteria she’ll have in her breast milk.