I have calcium, magnesium, and zinc altogether in one pill. it says to take 1 to 3 caplets daily with a meal. can i take all three at once, instead?

Med Directions: if it says 1-3 daily, then it means all at once. If it were to say take 1 tablet three times a day then it would mean exactly that. If it said to take one tablet up to three times a day then it would be how your are interpreting the directions. According to what you said the correct way is the first, 1-3 tablets all at once, one time a day.