Google+ Api get user email

I am creating a Sign Up With Google+ API. When inserting data into my Users table, I want to get the user's email. I get an error when trying to do that. My code looks like this:

var API_KEY = 'A*****';         

plus.people.get({
    auth: API_KEY,
    userId: req.body.userID
}, function (err, user) {
    if( err ) { res.json( JSON.stringify( err ) );  return; }
    console.log(user.emails);

    User.find({ where:{ social_id:req.body.userID, type: 2 } }).then( existingUser =>{              
    if( existingUser ) throw new Error('social_user_existing');
    if(!existingUser){
    User.build({
        username: user.displayName,
        social_id : req.body.userID, 
        social_token :req.body.token, 
        type : 2
        }).save();                      
    }                          
    }).then(function( new_g_user ){                 
        return res.json( rs.success({ username: user.displayName, user_id: user.id, jwt: new_g_user.getJwt() }) );
    }).catch(function(err){
        res.json( rs.errorCode(err.message) );
    });   
});     

I tried to get the email of the user with user.emails and user.emails[0].value to get at least the value of the first email. Each time, the response was 'undefined'. I mention that user.kind is 'plus#person', not "plus#personOpenIdConnect". Can this cause the response I get? Thank you!

via Emanuela colta