diff --git a/README.md b/README.md
index 4695439..050377f 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,11 @@ rollup({
 }).then(...)
 ```
 
-All options are as per the [Babel documentation](https://babeljs.io/), except `options.externalHelpers` (a boolean value indicating whether to bundle in the babel helpers), `options.include` and `options.exclude` (each a minimatch pattern, or array of minimatch patterns), which determine which files are transpiled by Babel (by default, all files are transpiled).
+All options are as per the [Babel documentation](https://babeljs.io/), except the following:
+
+   * `options.externalHelpers`: a boolean value indicating whether to bundle in the babel helpers
+   * `options.include` and `options.exclude`: each a minimatch pattern, or array of minimatch patterns, which determine which files are transpiled by Babel (by default, all files are transpiled)
+   * `options.externalHelpersWhitelist`: an array which gives explicit control over which babelHelper functions are allowed in the bundle (by default, every helper is allowed)
 
 Babel will respect `.babelrc` files – this is generally the best place to put your configuration.
 
diff --git a/src/index.js b/src/index.js
index 864f022..f93572f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -26,8 +26,12 @@ export default function babel ( options ) {
 	if ( options.externalHelpers ) externalHelpers = true;
 	delete options.externalHelpers;
 
+	let externalHelpersWhitelist = null;
+	if ( options.externalHelpersWhitelist ) externalHelpersWhitelist = options.externalHelpersWhitelist;
+	delete options.externalHelpersWhitelist;
+  
 	let warn = msg => console.warn(msg); // eslint-disable-line no-console
-
+  
 	return {
 		name: 'babel',
 
@@ -43,7 +47,7 @@ export default function babel ( options ) {
 			if ( id === HELPERS ) {
 				const pattern = new RegExp( `babelHelpers\\.(${keywordHelpers.join('|')})`, 'g' );
 
-				const helpers = buildExternalHelpers( null, 'var' )
+				const helpers = buildExternalHelpers( externalHelpersWhitelist, 'var' )
 					.replace( pattern, 'var _$1' )
 					.replace( /^babelHelpers\./gm, 'export var ' ) +
 					`\n\nexport { ${keywordHelpers.map( word => `_${word} as ${word}`).join( ', ')} }`;