By Giuseppe Monno
1. What is Transubstantiation?
Transubstantiation is the complete conversion of the substance of bread and wine into the substance of the Body and Blood of Jesus Christ, while the appearances (species) of bread and wine remain unchanged (color, taste, weight, and form). This doctrine was solemnly defined by the Catholic Church at the Fourth Lateran Council (1215) and reaffirmed at the Council of Trent (1545–1563).
2. What is the biblical foundation of the Eucharist?
The Eucharistic doctrine is founded upon the words of Jesus at the Last Supper and upon the discourse on the Bread of Life:
“This is my body.”
“This is my blood.”
(Matthew 26:26–28; Mark 14:22–24; Luke 22:19–20; John 6:51–58)
These words form the basis of the Catholic faith in the Real Presence.
3. What happens during the consecration?
During the Mass, the priest, by pronouncing the words of consecration and invoking the Holy Spirit, makes Christ truly present under the species of bread and wine.
Words of consecration:
Over the bread:
“Take this, all of you, and eat of it, for this is my Body, which will be given up for you.”
Over the wine:
“Take this, all of you, and drink from it, for this is the chalice of my Blood, the Blood of the new and eternal covenant, which will be poured out for you and for many for the forgiveness of sins. Do this in memory of me.”
4. In what way is Christ present in the Eucharist?
Christ is present truly, substantially, and wholly with his Body, Blood, Soul, and Divinity. This is called the Real Presence, because Christ is present truly and not merely symbolically or spiritually. He is entirely present in each species and in every smallest part of them.
5. What do “substance” and “accidents” mean?
Substance: what a thing truly is in its deepest reality.
Accidents: the properties perceptible to the senses (color, taste, weight, form).
In the Eucharist the substance of bread and wine is transformed into Christ, while the accidents remain those of bread and wine.
6. Who can validly consecrate the Eucharist?
Only a validly ordained priest can consecrate the Eucharist, acting in persona Christi, that is, in the very person of Christ.
7. What determines the validity of the Eucharistic celebration?
The validity depends on four elements:
1. Minister: a validly ordained priest.
2. Matter: bread made from wheat (in the Latin Church unleavened bread) and natural grape wine.
3. Form: the words of consecration pronounced in their essential form.
4. Intention: the priest must intend to do what the Church does.
8. Does the holiness of the priest affect the validity of the sacrament?
No. Even if the priest is in a state of sin, the sacrament remains valid, because it operates ex opere operato: its efficacy depends on the power of Christ, not on the personal holiness of the minister.
9. Is the Eucharist merely a symbol?
No. The bread and wine are not simple representations of Christ: they truly become his Body and Blood. The presence is real and substantial, not merely symbolic.
10. Do Catholics practice cannibalism?
No. Eating biological human flesh would be cannibalism. In the Eucharist one consumes the sacramental species of bread and wine while receiving Christ sacramentally and substantially, without chewing biological flesh.
11. In what sense does one “eat” the Body of Christ?
There are three levels:
1. Material: bread and wine are consumed.
2. Substantial: Christ is received.
3. Spiritual: grace is received.
What is perceived is bread and wine; what is truly received is Christ; the effect is spiritual nourishment for the soul and natural nourishment for the body.
12. Does the Eucharist also nourish the body?
Yes. The Eucharistic species retain the natural properties of bread and wine and therefore nourish the body, while grace nourishes the soul.
13. How long does the Real Presence of Christ remain?
Christ remains present as long as the sacramental species of bread and wine remain. When these cease to exist, the sacramental presence also ceases.
14. Does Christ end up in the sewer after digestion?
No. Christ’s presence is not material in a biological sense. When the sacramental species dissolve, the sacramental presence ceases, but Christ is neither degraded nor transformed into material substance.
15. Why are there hosts for people with celiac disease?
The substance is transformed, but the accidents remain unchanged. For this reason, low-gluten hosts exist for those with celiac disease. Those who suffer from severe gluten intolerance and cannot receive gluten may receive Holy Communion under the species of wine alone. Hosts completely without gluten would constitute invalid matter according to Canon Law.
16. If one receives only the wine, does one receive the whole Christ?
Yes. According to the doctrine of concomitance, Christ is entirely present in each species. Even a small sip of wine or a fragment of the host is sufficient to receive Christ whole and entire.
17. Is the Mass a new sacrifice?
No. The Mass sacramentally re-presents the sacrifice of Christ on the Cross:
On the Cross it occurred in a bloody manner.
In the Eucharist it occurs in an unbloody manner.
It is the same and unique sacrifice, not another.
18. Who offers the sacrifice of the Mass?
The principal subject is Christ himself. The Mass is offered by Christ, by the priest acting in persona Christi, and by the Church: the faithful, the angels, and the saints.
19. For whom are the fruits of the Eucharist beneficial?
The spiritual fruits benefit the faithful on earth and the souls in Purgatory.
20. Was the Eucharist prefigured in the Old Testament?
Yes. The manna in the desert and the nourishment given by God to his people prefigure the Eucharistic gift.
21. Why do we adore the Eucharist?
Because in it the Lord, living and glorified, is truly present and worthy of adoration under the species of bread and wine.
22. What is the deepest meaning of the Eucharist?
It is the real presence of Christ, the sacrifice made present, communion with God, nourishment for the soul, and a foretaste of eternal life. It is the supreme gift of divine love that unites heaven and earth.
23. What are the most common errors in explaining transubstantiation?
– Saying that bread becomes biological flesh
– Saying that one eats material flesh
– Reducing the Eucharist to a symbol
The correct formulation is:
“The substance of bread and wine is converted into the substance of the Body and Blood of Jesus Christ, while the accidents remain those of bread and wine.”
24. How can science analyze a consecrated host?
It cannot detect Christ, because science studies only material and physical properties (the accidents). The substance has become Christ, but the accidents remain bread and wine. The transformation is sacramental and substantial, not chemical or biological.
25. How can accidents exist without a substance?
Normally accidents cannot exist without a substance. In the Eucharist the accidents of bread and wine remain without their natural substance, sustained directly by the power of God. This is the permanent miracle of the Eucharist.
26. How can Christ be entirely present in many hosts simultaneously in different places?
Christ is present sacramentally, not materially. He does not occupy physical space but is present according to his substance.
He is entirely present in every host, even in the smallest fragment.
He is present simultaneously in many places.
He is neither divided nor multiplied.
The accidents remain sustained by the power of God, as taught by Saint Thomas Aquinas.
27. What is miraculous about the persistence of the accidents?
It is an invisible miracle: the entire substance of bread and wine is converted into the substance of the Body and Blood of Jesus Christ, while the accidents remain those of bread and wine.
28. What happens in Eucharistic miracles such as the one at Lanciano?
The accidents are visibly transformed into flesh and blood.
29. Is the visible flesh and blood in Eucharistic miracles the glorified Body of Christ?
No. They are a sensible sign of his real presence in the Eucharist.
30. Why do these miracles make the presence of Christ perceptible?
Because they reveal what normally remains hidden under the species of bread and wine.
31. How can the mystery of Transubstantiation be summarized?
The accidents remain bread and wine.
The substance is converted into Christ.
The faithful truly receive Christ.
The effect is grace and divine life.
32. How can Transubstantiation be explained in one simple sentence?
Under the species of bread and wine there is the living and substantial reality of Christ, perceived by the senses as bread and wine but received by the soul as the Body and Blood of the Lord.