sorry if you dont like what i am about to say and excuse my brashness...but centrum vitamins are some of the worst vitamins you can possibly take..you might as well swallow some rocks..they are garbage and save your money and forget about it...however you may take them during the fast yes...but they wont do ya any good...if you really wanna feel good off some vitamins...switch to a whole food supplement you mix with water...your body assimilates that much better....I am using Dr Schulzes SUPERFOOD ...there are many green food drink powders on the market...there are also different kinda whole food supplements...most vitamins and what not sit like rocks in your body calcifying your body cannot process it...ONE A DAY and CENTRUM are the top 2 worst multi vitamins ...ask anyone who knows.. but sure as much support as you can give your body to aid its fasting the better...poke around curezone for better alternatives.....hehe good luck on the fast