In the normal state, blood has no business anywhere except in the confines of the heart and blood vessels and in the sinusoids of the marrow, liver, and spleen. Of the average 5 L of blood, only 2.25 L, or 45%, consists of cells.
Take-away: Calcium and magnesium may best be taken in the evening with food or before nighttime sleep. Since zinc should not be taken with calcium and apart from iron, it is most useful if taken earlier in the day either slightly before/after food. Iron should ideally be taken on an empty stomach and separately from other multivitamin/multimineral combinations.
Zinc, if taken within 24 hours of the first sign of cold symptoms, reduced the duration and severity of the common cold in otherwise healthy adults and children. This was the case if adults used lozenges and children used zinc syrup. For children, one study showed that zinc sulfate syrup in a dose of 15 mg of zinc per day may prevent colds while 30 mg of zinc per day given at the first signs of symptoms may modestly treat a cold [2]. Zinc can be toxic so a pediatrician should be ...