The prefect of the Congregation for Divine Worship and the Sacraments, Cardinal Robert Sarah made the announcement in a letter issued to diocesan Bishops on behalf of Pope Francis.
In that letter, Cardinal Robert Sarah said the bread can be low-gluten and made from genetically modified organisms. However, there must be sufficient protein in the wheat to make it without additives.
According to the Vatican, the new rules have been introduced because the bread now sold is available in supermarkets and on the internet
The letter states: "The bread used in the celebration of the Most Holy Eucharistic Sacrifice must be unleavened, purely of wheat, and recently made so that there is no danger of decomposition.
"It follows therefore that bread made from another substance, even if it is grain, or if it is mixed with another substance different from wheat to such an extent that it would not commonly be considered wheat bread, does not constitute valid matter for confecting the Sacrifice and the Eucharistic Sacrament."
In a ruling set to affect a total of 1.2 billion Catholics globally, the instructions also specified that the wine used must also be "natural, from the fruit of the grape, pure and incorrupt, not mixed with other substances".
According to Roman Catholic doctrine, bread and wine served at the Eucharist are converted into the body and blood of Christ through the process of transubstantiation.