diff --git a/src/ItemHydrator.php b/src/ItemHydrator.php
index 8f948c0..4089140 100644
--- a/src/ItemHydrator.php
+++ b/src/ItemHydrator.php
@@ -48,7 +48,7 @@ public function hydrate(ItemInterface $item, array $attributes): ItemInterface
      */
     protected function fill(ItemInterface $item, array $attributes = null)
     {
-        $item->fill($attributes);
+        $item->fill(array_diff_key($attributes, array_combine($item->getAvailableRelations(), $item->getAvailableRelations())));
     }
 
     /**
diff --git a/src/Items/EloquentItem.php b/src/Items/EloquentItem.php
index dacd280..203b60a 100644
--- a/src/Items/EloquentItem.php
+++ b/src/Items/EloquentItem.php
@@ -119,7 +119,7 @@ public function getAvailableRelations(): array
      *
      * @return \Swis\JsonApi\Collection
      */
-    public function getIncluded()
+    public function getIncluded(): Collection
     {
         $included = new Collection();
 
@@ -128,12 +128,14 @@ public function getIncluded()
                 if (!empty($relation->getType()) && null !== $relation->getId()) {
                     $included->push($relation->toJsonApiArray());
                 }
+                $included = $included->merge($relation->getIncluded());
             } elseif ($relation instanceof IlluminateCollection) {
                 $relation->each(
-                    function (ItemInterface $item) use ($included) {
+                    function (ItemInterface $item) use (&$included) {
                         if (!empty($item->getType()) && null !== $item->getId()) {
                             $included->push($item->toJsonApiArray());
                         }
+                        $included = $included->merge($item->getIncluded());
                     }
                 );
             } else {
@@ -141,6 +143,10 @@ function (ItemInterface $item) use ($included) {
             }
         }
 
-        return $included;
+        return $included->unique(
+            function (array $item) {
+                return $item['type'].':'.$item['id'];
+            }
+        );
     }
 }
diff --git a/src/Items/JenssegersItem.php b/src/Items/JenssegersItem.php
index 6cf5cb5..ae91eb2 100644
--- a/src/Items/JenssegersItem.php
+++ b/src/Items/JenssegersItem.php
@@ -183,7 +183,7 @@ public function getRelationships(): array
      *
      * @return \Swis\JsonApi\Collection
      */
-    public function getIncluded()
+    public function getIncluded(): Collection
     {
         $included = new Collection();
 
@@ -192,17 +192,19 @@ public function getIncluded()
                 continue;
             }
 
-            if ($relationship->getIncluded() instanceof ItemInterface) {
-                $item = $relationship->getIncluded();
-                if (!empty($item->getType()) && null !== $item->getId()) {
-                    $included->push($item->toJsonApiArray());
+            $includedFromRelationship = $relationship->getIncluded();
+            if ($includedFromRelationship instanceof ItemInterface) {
+                if (!empty($includedFromRelationship->getType()) && null !== $includedFromRelationship->getId()) {
+                    $included->push($includedFromRelationship->toJsonApiArray());
                 }
-            } elseif ($relationship->getIncluded() instanceof Collection) {
-                $relationship->getIncluded()->each(
-                    function (ItemInterface $item) use ($included) {
+                $included = $included->merge($includedFromRelationship->getIncluded());
+            } elseif ($includedFromRelationship instanceof Collection) {
+                $includedFromRelationship->each(
+                    function (ItemInterface $item) use (&$included) {
                         if (!empty($item->getType()) && null !== $item->getId()) {
                             $included->push($item->toJsonApiArray());
                         }
+                        $included = $included->merge($item->getIncluded());
                     }
                 );
             } else {
@@ -210,7 +212,11 @@ function (ItemInterface $item) use ($included) {
             }
         }
 
-        return $included;
+        return $included->unique(
+            function (array $item) {
+                return $item['type'].':'.$item['id'];
+            }
+        );
     }
 
     /**