Two other aspects of oatmeal that have been mentioned in previous posts -- there was a thread on this several months back -- were: that oatmeal is also high in iron, and therefore especially helpful for moms who have had a major blood loss, or for other reasons dropped their Hgb and Hct; and that oatmeal is also a comfort food, perhaps not making more milk, but allowing more relaxation and therefore increased letdown, as well as perhaps, increased supply.
Chanita, San Francisco