diff --git a/lib/dao.js b/lib/dao.js
index 4ed71b3e..00fbf18c 100644
--- a/lib/dao.js
+++ b/lib/dao.js
@@ -1175,6 +1175,10 @@ DataAccessObject.prototype.updateAttributes = function updateAttributes(data, cb
             // Convert the properties by type
             inst[key] = data[key];
             typedData[key] = inst[key];
+            if (typeof typedData[key] === 'object' 
+              && typeof typedData[key].toObject === 'function') {
+              typedData[key] = typedData[key].toObject();
+            }
           }
 
           inst._adapter().updateAttributes(model, getIdValue(inst.constructor, inst),