DEAR PEGGY: Every physician I've seen has told me how much calcium I need in milligrams, but food labels list it in percent daily value. This is confusing because all people likely don't need the same amount of calcium. How can I calculate calcium in milligrams based on food labels? —B.S., Gainesville, Florida
You're right. Different age groups and people with certain health conditions need different amounts of calcium, so having one general daily value can be confusing. The percent daily values on food labels show whether a food is high or low in a nutrient. They're meant to help you make healthful decisions, but they don't offer a perfect system.
The calcium listed on food labels is based on 1,000 mg per day. With that know-how, you can calculate the percentage into milligrams.
For example, a food with calcium listed at 7% DV would be calculated this way: .07 x 1,000 mg = 70 mg calcium per serving.