Thomas_Aquinas_by_Fra_Bartolommeo Denys Turner on St. Thomas, Eucharist and matter:
Herein is the reason why the Eucharist appeals so directly to Thomas. It connects with such immediacy and force to the driving energy of his theology, to what I have called his “materialism.” For Thomas, if you are looking for meaning you will find it in matter, and no more strikingly could this methodological principle be embodied than in the theology of the Eucharist. The Eucharist reveals something unexpected there in the meanings we achieve by eating and drinking together which, without the
Eucharist, we could not know at all. And so what Thomas says about the relation of the Eucharist to food is this: you do not fully understand the
human meaning of food until you understand its Eucharistic depth: lurking within the quotidian business of meals is a mysterious dimension, waiting to be disclosed. The Eucharist discloses it (237).
As Turner continues about the seemingly surprising claims of Thomas’s Eucharistic theology,
You wouldn’t have known that mere bread and wine could bear such weight of meaning, for basic human food is the last place you would guess to be the point of entry into the mystery of the world’s creation out of nothing and its trajectory through history to its final end in the eternal love that created it. For Thomas it is all there in the meaning of eating and drinking. And it should not surprise us that all the meaning of all the world is contained and hidden in that holy hiddenness. If it is a cause of surprise that theology should culminate there, in Christ’s followers eating and drinking together, then there is still something to learn from Thomas (267-268). 

A.A. has much of importance to offer in the way of meaningfulness, too, I should add - but it doesn't really have this speculative aspect.   Perhaps this is because its only Sacrament is talking - which, like marriage, is highly dependent on the persons involved, and doesn't lend itself as well to philosophical elaboration.

Maybe I'll talk about that sometime, in fact....