Milk, once considered nature's perfect food, has become the target of a vocal number of vegetarian groups and even some doctors who claim that it is responsible for a wide range of childhood diseases, from acne to juvenile diabetes.
The message has filtered down to parents, and many are worried. But many health experts say an even greater concern should be whether children are getting enough calcium.
The three charges leveled against cow's milk:
- Do the hormones in milk contribute to early puberty?
- Are the antibiotics given to cows making our children resistant to antibiotics prescribed by doctors for childhood diseases?
- Does milk make children susceptible to juvenile diabetes?
Because of worries about milk safety and the popularity of soda pop, milk consumption has plunged in recent years. For example, milk drinking among girls ages 12 to 19 dropped 38 percent and pop consumption soared 91 percent from 1978 to 1996, according to the U.S. Department of Agriculture.
"Families don't serve milk and kids don't drink it," said Sally Phillips, a dietitian at Children's Hospital Medical Center of Akron.
The switch from milk to soda pop has caused what some are calling a calcium crisis among the young. Lack of calcium in childhood can lead to osteoporosis in adulthood. Calcium also is important for nerve conduction, muscle contraction and blood clotting, and may help reduce the risk of high blood pressure and colon cancer.
In their crucial bone-formation years, healthy children ages 9 through 17 need 1,300 milligrams of calcium a day, about the amount in four cups of milk.
"The data is out there that says we need calcium in our youth to lay down bone mass. And the best and easiest source of calcium is milk," said Dr. Ellen Kempf, an Akron pediatrician and director of the pediatric primary-care network at Children's Hospital.
But other health professionals, including the late Dr. Benjamin Spock, disagree. In 1998, in the final edition of his revered child-rearing book, "Baby and Child Care," Spock urged parents to stop giving cow's milk to their children, period.
Milk is a "hormonal delivery system" that is sending children into puberty alarmingly early, said Robert Cohen, author of the 1998 book "Milk: The Deadly Poison."
Girls in the United States are developing breasts as early as 8 years old. Cohen said the reason is the growth hormones that are given to many dairy cows to boost milk production. The hormones certainly have affected cows, who can produce an average of 24 quarts of milk daily now, up from eight quarts in 1960.
Cohen concedes that no scientific studies have linked milk consumption to early maturation. That's because the link probably does not exist, other physicians and researchers say. Hormones are short-lived, so it is doubtful that they survive in milk until the carton reaches the grocer's shelf.
"It's very unlikely you will find a high concentration of hormones in milk or even meat," said Dr. Ines Guttman-Bauman, an endocrinologist at Children's National Medical Center in Washington, D.C.
Early puberty instead may be the result of chemicals in plastics, increased protein consumption or even obesity. "Fat tissue seems to produce substances that initiate early sexual development," Guttman-Bauman said.
She said research into all of these areas is just beginning. And whether early puberty is even occurring is debatable, she said.
In the last 40 years, there has been no change in the average age at which American girls get their first menstrual periods--about 12 1/2. Secondary sexual characteristics such as pubic hair and breast development may occur earlier than in decades past, but there's no data to back up the observation.
Americans are becoming more and more resistant to the antibiotics used to treat infections. Milk opponents say the reason is more and more antibiotics are being given to animals.
Dairy cows in particular are being given more antibiotics because of the increased problem of mastitis brought on by hormone-boosted milk output, said Dr. Colin Campbell, professor of nutritional biochemistry at Cornell University.
Traces of antibiotics fed to cows show up in about one-third of cow's milk products, contends the Physicians Committee for Responsible Medicine, a Washington group that promotes vegetarianism. The consumption of antibiotics in cow's milk then leads to antibiotic resistance in humans, the committee said.
"That's kind of National Enquirer stuff. It's not sound or scientifically based," said Kempf of Children's Hospital.
It is blatantly false, said Kathryn Boor, a microbiologist and associate professor of food science at Cornell. Since 1993, milk has been strictly tested for antibiotics and milk that tests positive is discarded. The Milk and Dairy Beef Residue Prevention program is overseen by the Food and Drug Administration and enforced by the FDA, the states and the milk industry.
"When the milk is picked up and goes to the plant, every single truckful is tested for antibiotics," Boor said. "For there to be antibiotics in the milk would be extremely rare."
That wasn't always the case. "This is something that has improved dramatically in the last decade," Boor said.
Milk opponents say juvenile diabetes is caused solely by consumption of cow's milk. Researchers have found that lactolbumin, a protein in cow's milk, causes humans to produce an antibody. The antibody destroys the lactolbumin. But sometimes it also turns on human beta cells, which manufacture insulin in the pancreas and closely resemble lactolbumin. When the beta cells are destroyed, juvenile diabetes results.
"What we know is that all kids with juvenile diabetes have these antibodies. Milk is the cause-- the only cause -- of these antibodies," said Amy Lanou, who has a doctorate in human nutrition and is nutrition director of the Physicians Committee for Responsible Medicine.
Even people with adult-onset (Type 2) diabetes could improve their health by cutting out milk, Cohen said.
"It's complete nonsense," Guttman-Bauman said. "Type 2 diabetes has nothing to do with milk."
Juvenile-onset diabetes may, though. Milk's link with diabetes began with a 1984 Scandinavian study that found that children who were breast-fed were less likely to develop juvenile-onset diabetes than children who were formula-fed.
More recently, Finnish researchers concluded that children who have siblings or parents with diabetes were less likely to develop diabetes themselves if fed a formula that wasn't based on cow's milk.
The study used a small sample and more tests are needed. "It may be that in people who are genetically at risk, consumption of milk may provoke diabetes," Guttman-Bauman said. Studies are under way, and the results should be known within a decade. Until then, the American Academy of Pediatrics recommends that no children younger than 1 be given cow's milk (this sentence as published has been corrected in this text).
In addition, Phillips said families with a history of diabetes should strongly consider nursing children younger than 1. After age 2, though, cow's milk is recommended for children by most major health groups and health professionals.
The American Dietetic Association recommends three servings a day of milk or dairy products for healthy children ages 2 to 11 who are not lactose-intolerant.
"`It is very difficult to meet children's calcium needs without a source of milk in the diet," the association wrote in a position paper on calcium.
The American Academy of Pediatrics in November increased its stress on milk by encouraging pediatricians to talk to children and their parents about dairy products, and urge that they be served daily to healthy children. The group also for the first time recommended calcium supplements for children 9 to 18 who cannot or will not get enough calcium from foods.
"Through the ages, the benefits of milk have been much higher than any of the side effects," Guttman-Bauman said. "It has protein. It has calcium. It's good food."