That is a great question!
In my experience, the last thing people want to do is lug a big bag of supplements on holiday or vacation. (See my previous post, Am I Taking Too Many Supplements?) And there is some evidence that we respond better to supplements if we pulse them, in other words, take supplements, then stop for a while, then resume taking them. If this is true then why not take a personal holiday combined with a supplement holiday?
On a more serious note, there are some important supplements that I would recommend if you are traveling to a less developed area of the world. In these places you will be undoubtedly exposed to various "bugs" that, while harmless to indigenous people, may make you sick. I find the best preventative measures include avoiding organ meats, raw shellfish, undercooked foods and of course local water sources. But, even if you are just going to grandma's for a few days, a good preventive measure is to supplement your gut and help you balance the good flora with the stress of traveling and unfamiliar food.
Supplements to Take When Traveling: