A: Major brands are selling orange juice with about 350 milligrams of calcium and 100 international units of vitamin D added to each 8-ounce serving. Many Americans don't get enough vitamin D, so I am happy to see the addition of vitamin D. I have some concerns about the additional calcium.
A reasonably well-balanced American diet provides about 300 mg of calcium a day. Calcium is an essential nutrient, and we certainly need some for healthy bones and other critical functions. But beyond about 800 mg a day — and it might be as little as 400 to 500 mg — there doesn't appear to be much additional benefit, except, perhaps, some slight protection against colon cancer. And in large amounts, calcium may cause some harm. Studies have found an association between calcium supplements and kidney stones. Other research has linked large amounts of calcium in the diet to an increased chance of heart attack or stroke. I am not totally convinced that there's a causal connection, but you don't have to be totally convinced to be cautious.
In general, I think we should just let orange juice be orange juice and not load it up with other chemicals even if they are essential nutrients. Also, we need to be cautious about even 100 percent natural juices because of the calories (more than 100 per 8-ounce serving of orange juice) and the sugar (more than 20 grams).