Taking Calcium Supplements: What You Need to Know

Knowing when to take calcium supplements depends on many factors, including other supplements or medications you are currently taking, the type of supplement you intend to use, and the timing and amount of your dose. Using calcium supplements properly can mean the difference between getting the optimum amount of calcium for your needs or wasting what calcium you ingest. Taking calcium supplements at the wrong time or with the wrong foods can negate the effects of medications and other supplements, and can reduce your body’s ability to absorb sufficient levels of the mineral.

The type of calcium supplement you are taking directly affects when and how often it should be taken. Reading the label on your calcium supplement package will tell you if it is sourced from calcium citrate or calcium carbonate, the two most common forms of supplemental calcium. Calcium carbonate is best taken with food as stomach acid breaks down this type of calcium and helps in the absorption process. Calcium citrate can be taken alone, with or without food.

For either supplement, the time of day your dose is taken does not matter. However, because the body can only absorb up to 500 mg of calcium effectively at one time, higher doses should be split up and taken several times throughout the day - perhaps in the morning, afternoon, and evening. If you are eating calcium-rich foods, take your calcium supplement a few hours before or after your meal if the total amount of calcium will exceed 500 mg. If you are taking calcium carbonate, take it with your least calcium-rich meals to avoid topping the 500 mg level.

Calcium can interfere with the absorption of iron and magnesium. If you are taking an iron or magnesium supplement or are specifically eating iron-rich foods, take your calcium supplement at least two hours before or two hours after your iron or magnesium intake to avoid absorption problems with both nutrients.

Calcium can also interfere with prescription medications, including the antibiotic tetracycline. If you have been prescribed antibiotics, consult your pharmacist or family doctor about potential interactions between your medication and calcium supplements. In most cases, you will not need to interrupt your calcium supplementation, but you may need to adjust the time you take your daily supplement to prevent your body from attempting to absorb both your medication and your supplement together. It is always important that your pharmacist and doctor are both aware of any medications and nutritional supplements you are taking.