Understanding WordPress Menu Items | http://www.ibenic.com/understanding-wordpress-menu-items/

sample_page.php

<?php

function ibenic_custom_menu( $menu_item ) {
  // If we are in the admin area, skip this function
	if ( is_admin() ) {
		return $menu_item;
	}

	// If this isn't a Sample Page menu item, skip this function
	if ( $menu_item->title != "Sample Page" ) {
		return $menu_item;
	}

	if( !is_user_logged_in() ){
		$menu_item->_invalid = true;
	}
	
	// If there is no url, don't render it
	if ( empty( $menu_item->url ) ) {
		$menu_item->_invalid = true;
	} 
	return $menu_item;
}

add_filter( 'wp_setup_nav_menu_item', 'ibenic_custom_menu', 10, 1 );

wp_post_object.php

<?php

// Sample Page Menu Item
WP_Post Object ( 
  [ID] => 161 
  [post_author] => 1
  [post_date] => 2016-03-26 17:59:07 
  [post_date_gmt] => 2016-03-26 17:59:07 
  [post_content] => 
  [post_title] => 
  [post_excerpt] => 
  [post_status] => publish 
  [comment_status] => closed 
  [ping_status] => closed 
  [post_password] => 
  [post_name] => 161 
  [to_ping] => 
  [pinged] => 
  [post_modified] => 2016-04-06 14:09:26 
  [post_modified_gmt] => 2016-04-06 14:09:26 
  [post_content_filtered] => 
  [post_parent] => 0 
  [guid] => http://localhost/wordpress/?p=161 
  [menu_order] => 2 
  [post_type] => nav_menu_item 
  [post_mime_type] => 
  [comment_count] => 0 
  [filter] => raw 
  [db_id] => 161 
  [menu_item_parent] => 0 
  [object_id] => 2 
  [object] => page 
  [type] => post_type 
  [type_label] => Page 
  [url] => http://localhost/wordpress/sample-page/ 
  [title] => Sample Page 
  [target] => 
  [attr_title] => 
  [description] => 
  [classes] => Array ( [0] => ) 
  [xfn] => 
  )