Absorption of other vitamins in the body. Some precautions to be taken into account when taking supplements are gastric bypass message:maxx test 300 Do not consume vitamin supplements with milk or its products, as this interferes with iron absorption.Do not consume calcium along with other vitamin supplements.Keep a space of two hours between the consumption of iron and calcium supplements or dairy products. What is vegan is all this Veganism is a stricter version of vegetarianism..