June 11, 2012 | Most Arkansans need between one thousand to thirteen hundred milligrams of calcium every day. An eight ounce glass of whole milk contains 291 milligrams of calcium, a good start toward obtaining your daily requirement. Many Arkansans, however, have to rely on calcium-fortified foods like orange juice and cereal to get enough of the mineral because they are lactose intolerant. Lactose intolerance is the inability to digest significant amounts of lactose, the natural sugar found in milk and other dairy products. Close to 50 million American adults are lactose intolerant, with certain ethnic and racial populations more widely affected than others. The disorder is more common in some ethnic groups than in others. As many as 75 percent of all African-American, Jewish, Native American, and Mexican-American adults, and 90 percent of Asian-American adults, are lactose intolerant. The condition is least common among people of northern European descent.