Vitamin supplements?? WTF! A colony of humans couldn't survive on Mars by taking vitamin supplements. Literally all of their food would have to be shuttled from earth on an ongoing, regular basis; something that would result in the price of a cup of coffee being worth the equivalent of $10,000,000. Now apply that cost to the actual, basic sustenance that these people would have to consume on a daily basis to meet their minimum nutrition and calorie requirements.