Ester-C, a patented vitamin C compound composed of ascorbic acid and calcium, was developed in the 1980s and is now widely available as a dietary supplement. The supplement's manufacturers say it's more easily absorbed and less readily excreted from the body than standard vitamin C.
Uses: Ester-C can be used as a replacement for standard vitamin C tablets, which are often taken to boost immunity and fend off ills.
Dose: Supplement makers recommend 100 to 1,000 milligrams of Ester-C daily. The daily recommended intake for vitamin C is 60 milligrams.
Precautions: Ester-C, like vitamin C, is generally considered safe in large doses.
Research: Animal studies in the 1980s showed that rats absorbed Ester-C better than pure ascorbic acid and were less likely to develop scurvy when given Ester-C compared with ascorbic acid. But later studies in dogs and humans showed no significant difference in absorption rates between the different forms of the vitamin.
Dietary-supplement makers are not required by the U.S. government to demonstrate that their products are safe or effective. Ask your health-care provider for advice on selecting a brand.
-- Elena Conis