[The Squatter of Amon Rûdh]

It's interesting that Tolkien acknowledges but does not explicitly confirm one critic's equation of Lembas with the viaticum.

Another [critic] saw in waybread (lembas)=viaticum and the reference to its feeding of the will (vol. III, p. 213) and being more potent when fasting, a derivation from the Eucharist. (That is: far greater things may colour the mind in dealing with the lesser things of a fairy-story.)

Letters #213 (25 October 1958)

I'd certainly hesitate to equate Lembas with the viaticum, although it's not too much of a stretch to compare it with the communion host. There is something more to waybread than simple nutrition, though.

Originally Posted by JRRT

[Lembas] also has a much larger significance , of what one might hesitatingly call a 'religious' kind. This becomes later apparent, especially in the chapter 'Mount Doom' (III, 213 and subsequently).

Letters #210 (June 1958)

By this second comment, I assume Tolkien to mean that there is a spiritual element to the nourishment provided by the elven waybread; one which has a universally beneficial effect. There is no evidence that the elven rope or the lembas actually injure Sméagol, but he finds them hard to endure. I think that Gollum's reaction is intended to be typical of the fallen characters - those furthest from the service of the Valar. Perhaps the message is intentional that the further one progresses into evil the more distasteful become the means and products of good, until eventually they become impossible to endure. This suggests how great an effort of will it would take for Sméagol to be healed: he finds those things that will cure him painful to touch. When we compare LR to Carcharoth's swallowing of the Silmaril in the Silmarillion, we can see a more extreme example of the same process: evil things are burned by the most wholesome objects, although Sméagol is not so far gone that he is physically burned by the painful touch of elven artifacts.

Frodo's insight does not have to be conferred by the Ring. Of the hobbits he is the eldest, best educated and most thoughtful, so it would be natural that he would come to an understanding of Sméagol's plight with or without the influence he could feel from the Ring. I'm not suggesting for a moment that there wasn't a particular affinity between the two that stemmed from their bearing of the Ring, but it's not necessary for an understanding of his comments under discussion.