Estimada amiga,
Gracias por su mensaje y por el interés demostrado por nuestros productos. En relación a su consulta, le informamos que Nestea no contiene glúten ni derivados del glúten, y que por lo tanto creemos podría ser adecuados para pernonas celíacas.
No obstante, siempre recomendamos que sea el médico quien autorice el consumo de los mismos.
Reciba un cordial Saludo
Servicio de Atención al Consumidor
Coca Cola España
Yes, I know... It is in spanish...

Here is the translation:
Dear friend
Thank you for your message showing your interest in our products. In relation with your request, we inform you that NESTEA does not contain any gluten. Therefore, we think it could be appropriated for Celiacs.
Even though, we always recommend that your doctor authorizes the use of the previous mentioned products.
Kind Regards,
Consumer´s Assistance Service
Coca Cola España
They answered in just one day after my request...
What do you think about it?
Love,
Tessa.