For many other nutrients, you'd have to increase the adequate intake many times before reaching risky levels. Then, too, hypercalcemia, as toxicity of the mineral is called, can aggravate kidney stone formation, particularly for people who have had a stone in the past. High-calcium diets reduced zinc balance. While such problems have been rare until now, the plethora of calcium-fortified items now on supermarket shelves raises the threat of their becoming more common. Not that Wood thinks calcium-fortified foods are a bad thing.
Average intakes are much, much lower than the recommendations.
To be sure, women 20 to 29 years old average only about 700 milligrams of calcium a day, when they should be consuming 1,000 milligrams. And women 65 and older, who should be getting 1,200 milligrams, are taking in only about half that amount. It's a similar story for men, although the gap for them is often more on the order of 200 to 300 milligrams. Others agree that calcium-fortified foods are a reasonable option. And unlike Wood, he's not particularly concerned about anyone's going overboard.