Vitamins?!

I assume by low carb, you're shooting for ketosis? If so, you're going to be tired for a while. You'll eventually get used to it, but how quickly you get used to it is different for each person.

Frankly, I don't think vitamins will help with the fatigue. You're tired because your body wants glucose. So you either need to cave and give your body glucose, or you need to push through the tired until your body gives and accepts that you're now a carnivore.

However, if you want vitamins, any good mulit-vitamin should have what you need. You don't need to go hog-wild on any of them. If you eat more vitamins than your body needs, you'll pee/poop out the water-soluble ones and store the fat soluble ones. The fat soluble ones can cause health problems if you take too many. Fat soluble vitamins are: A, D, E, and K. You can OD on some vitamin Bs too (they're not fat soluble), but that's pretty hard to do. Actually, you have to work to OD on the fat soluble ones too. A daily multi-vitamin won't do it. Just don't go taking 5000 times the recommended daily amount.

You're probably good on iron if you're eating red meat. But... you could take an iron pill too if you wanted. If your anemic at all (which can cause fatigue), then the iron will help.

This is all my semi-educated, non-professional opinion as someone who works in a health related field and who's tried a ketogenic diet before deciding to do something else. I felt sick on the ketogenic diet.