There are few alternatives to the mandatory beverage in the National School Lunch Program.
Khalil Beckwith has never been formally diagnosed with lactose intolerance. He just knows that drinking milk makes him feel lousy.
"When I drink milk with nothing else ... finishing the carton can be a nauseating endeavor," said Beckwith, a senior at King College Prep High School in Chicago.
Like millions of other American children, when Beckwith takes a meal through the federal school lunch program, milk is the only beverage available. Usually he avoids drinking it, but sometimes he said he feels pressure to take the milk. Then he either throws it away or winds up feeling queasy.
People with lactose intolerance lack the enzymes needed to digest lactose, resulting in bloating, cramping, nausea and diarrhea after milk consumption. The condition is common among African-Americans like Beckwith, as well as Hispanics, Asians and American Indians.
Schools participating in the National School Lunch Program -- including those in the Twin Cities -- must serve milk, and school officials say the only way a student can receive a substitute drink is for a doctor to say he or she has a milk allergy. That is a different condition, which qualifies as a disability.
In Minneapolis public schools, students may be served lactacid milk with a parent's signature, but if a student wants rice or soy milk, the student needs to present a medical doctor's signature. A doctor's note is required because of reimbursement requirements from the state of Minnesota, said Syreeta Wilkins, a Minneapolis schools spokeswoman.
The U.S. Department of Agriculture (USDA), which runs the lunch program, says it is acceptable to give students an alternative (such as lactose-free milk, soy milk or almond milk) if a parent submits a simple request.
"USDA provides schools with the flexibility to offer milk substitutes that meet federal nutrition requirements to accommodate students' nondisabling allergies, culture, religion or ethical beliefs," a spokeswoman said.
Estimated rates of lactose intolerance among minority groups range from 50 to 100 percent, though a national conference on the topic in 2010 concluded that good data on prevalence remain elusive. Even the lowest estimates, however, suggest that millions of children in the federal lunch program could experience gastrointestinal problems after consuming milk.
And although the USDA allows schools to provide a substitute, those products tend to be more expensive, discouraging officials from publicizing the option. In Minneapolis public schools, milk is the only beverage offered at lunch.
"No juice is available for students," Wilkins said.
The lack of choices worries parents and health advocates who believe it will leave lactose-intolerant students feeling sick and contribute to massive waste. An audit at one Chicago school found that a third of the milk taken at lunch was thrown away.
"If they are required to take milk during lunchtime and actually drink it, how are they going to feel after lunch sitting in that classroom?" said Amy Lanou, an assistant professor of nutrition at the University of North Carolina in Asheville. "Are they going to behave? Are they going to be focused on their studies?"
Lactose-intolerant students got some federal help last year, when the USDA began requiring schools to provide free drinking water in all lunch service locations.
"There are drinking fountains in the [Minneapolis] lunchrooms, and students can ask for a cup and drink from that," Wilkins said.
The USDA says milk is a required part of the lunch program because it provides "children with the calcium and vitamin D, as well as protein, needed to develop strong bones, teeth and muscles." In most districts, students don't have to take milk with lunch, but it must be offered.
In addition, the USDA will not reimburse schools for a lunch unless it contains a certain number of food items. So if a student reaches the end of the cafeteria line with, say, a meat patty and broccoli, the lunch worker is likely to suggest adding milk to complete the meal.
"We do not force kids to take milk, but we do suggest that they take it for breakfast and lunch," Wilkins said.
Staff writer Alejandra Matos contributed to this report.