CathInfo.com

From Tradition the fast was very strict, no food or water allowed from midnight the night before, not even a drop of water. This would of course, exclude some water swallowed in accidentally if one was cleaning their teeth.

Pius XII changed this to 3 hours for solid foods and 1 hour for non-alcoholic liquids.

and,

"The infirm, even if not bedridden, may take nonalcoholic liquids and that which is really and properly medicine, either in liquid or solid form, before Mass or Holy Communion without any time limit."

Vitamin D (unless it is really and properly a medicine - doctor prescribed) would not apply.

1957
https://www.papalencyclicals.net/pius12/p12fast.htm

The main thing to remember, is that all this lessening of the Eucharistic Fast was supposedly because of the clamor of bishops who wanted to have more afternoon/evening Masses.

Pius XII still exhorted the faithful who were able to observe the midnight fast:

1953
https://www.papalencyclicals.net/pius12/p12chdom.htm

Within he stated,

"The law of the Eucharistic fast from midnight continues in force for all of those who do not come under the special conditions which We are going to set forth in this Apostolic Letter. In the future it shall be a general and common principle for all, both priests and faithful, that natural water does not break the Eucharistic fast."

The real thing one should ask themselves is why did the Church preserve the midnight fast from food and drink for so many centuries? The answer is of course to foster greater devotion to the Blessed Sacrament. Christ is the sustenance of soul and body, He is the "Bread that came down from heaven". He is the "fountain of living water", etc. Mortifying the flesh through fasting draws the mind to heavenly things and makes us more fit to participate in the heavenly mysteries.

IMO, we must do the minimum (3 hr. food/1hr. drink), and we are "good", but, if possible, we should do the Traditional thing, and we are doing "better" by observing the midnight fast as called for by Pius XII.  In the end, it is us that wins out, because we are the poor beggars who need grace and God sees with what spirit we approach Him at the Altar and main thing is to have humility of heart - fasting helps foster this spirit if it done with that intention. Though it does take some getting use to.

It is there in the body of the text I already cited,

"The law of the Eucharistic fast from midnight continues in force for all of those who do not come under the special conditions which We are going to set forth in this Apostolic Letter. In the future it shall be a general and common principle for all, both priests and faithful, that natural water does not break the Eucharistic fast."

God bless you