Lookup column from SharePoint list returns limited values in Word.

Issue:

Document information panel (aka Ribbon) in word only lookup 30 items from SharePoint list which have around 500 items.

Solution:

Document Information Panel (aka the Ribbon) uses the default view list of a lookup column to determine how many items to show in a dropdown list

Parameter Item Limit in view settings need to be adjusted according to the number of items present in column of the list as shown below.

Courtesy:  http://www.brainlitter.com/2010/07/23/document-information-panel-ala-the-ribbon-uses-the-default-view-list-of-a-lookup-column-to-determine-how-many-items-to-show-in-a-dropdown-list/