Vitamins

Vitamins can be called by a number of different names. Here are some for your MeSH, keyword-searching and Word-highlighting use:

Vitamin A:

Mesh: "Vitamin A"[Mesh] OR "Vitamin A Deficiency"[Mesh]

keywords: "vitamin a"[tiab] OR retinol*[tiab] OR tretinoin[tiab]

There also seems to be a connection to carotene: caroten*[tiab]


Vitamin B:
There are actually a whole bunch of Vitamin Bs, and apparently some of them are other vitamins as well (Vit G, H, and M). Because, you know, that's not confusing at all!

I recommend use of Ovid for this one so that you can use truncation.
Mesh: exp Vitamin B Complex/ or exp Vitamin B Deficiency/
keywords: (vitamin b* or cobalamin* or cyanocobalamin* or hydroxycobalamin* or riboflavin* or vitamin g or biotin or vitamin h or niacin or thiamin* or adenine or pantothenic acid or pantothenate or folic acid or folate or vitamin m).mp.

However, PubMed does have a Pharmacological Action for Vitamin B Complex, which might be useful as well.
Mesh: "Vitamin B Complex"[Mesh] OR "Vitamin B Complex"[Pharmacological Action] OR "Vitamin B Deficiency"[Mesh]

Vitamin C:

Mesh: "Ascorbic Acid"[Mesh] OR "Ascorbic Acid Deficiency"[Mesh]

Watch out for this one in Ovid. The mapping is broken and it maps to Vitamin D instead of Ascorbic acid. This has been reported to Ovid, but so far they have not been able to fix it. In PubMed it maps just fine.

keywords: "vitamin c"[tiab] OR "ascorbic acid"[tiab] OR ascorbate[tiab] OR ascorbium[tiab]

Vitamin D:

Mesh: "Vitamin D"[Mesh] OR "Vitamin D Deficiency"[Mesh]

"vitamin d"[tiab] OR cholecalciferol*[tiab] OR ergocalciferol*[tiab] OR dihydrotachysterol*[tiab] OR hydroxycholecalciferol*[tiab] OR "25 hydroxyvitamin d2"[tiab] OR "25 hydroxyvitamin d 2"[tiab]

Vitamin E:

Mesh: "Vitamin E"[Mesh] OR "Vitamin E Deficiency"[Mesh]

keywords: "vitamin e"[tiab] OR tocopherol*[tiab] OR tocotrienol*[tiab]

Vitamin F:

Mesh: "Arachidonic Acid"[Mesh]

keywords: "vitamin f"[tiab] OR "arachidonic acid"[tiab] OR arachidonate*[tiab] OR "eicosatetraenoic acid"[tiab] OR eicosatetranoate*[tiab]

Vitamin K:

Mesh: exp Vitamin K/ or exp Vitamin K Deficiency/

Once again, Ovid for the truncation:

keywords: (vitamin k* or phytomenadione* or menaquinone* or menadione* or phytonadione* or phylloquinone*).mp.

If you really need to use PubMed:
Mesh: "Vitamin K"[Mesh] OR "Vitamin K Deficiency"[Mesh]

keywords: "vitamin k"[tiab] OR "vitamin k 1"[tiab] OR "vitamin k1"[tiab] OR "vitamin k 2"[tiab] OR"vitamin k2"[tiab] OR"vitamin k 3"[tiab] OR"vitamin k3"[tiab] OR phytomenadione*[tiab] OR menaquinone*[tiab] OR menadione*[tiab] OR phytonadione*[tiab]

Vitamin U:

This one would be better in Ovid as well, for adjacency:

keywords: (vitamin u or methymethionine).mp. or (methylsulfonium adj3 methionine).mp. or (methylsulphonium adj3 methionine).mp.
Mesh: exp Vitamin U/

But if not, PubMed can do this for you:

Mesh: "Vitamin U"[Mesh]
keywords: "vitamin u"[tiab] OR "methymethionine"[tiab] OR ("methylsulfonium[tiab] AND "methionine"[tiab]) OR ("methylsulphonium[tiab] AND "methionine"[tiab])