"Drink Milk Every Morning?"

Although calcium can be obtained from foods other than milk, as well as from supplements, it is the main source of this vital nutrient for young Americans. Few children or adults consume enough cheese and nondairy calcium-rich foods, like collard greens or broccoli, to meet the daily calcium requirements.

Some people avoid milk because they are lactose-intolerant and experience flatulence or diarrhea when drinking the milk on an empty stomach.

The National Academy of Sciences says that children ages 4 through 8 should be consuming 800 milligrams of calcium daily and that teenagers 13 through 18 need 1,300. People 19 through 50 need 1,000 milligrams of calcium a day, and those 51 and older are urged to consume 1,300 milligrams, the academy says.

A national survey in the mid-1990`s, however, revealed that only 13.5 percent of girls and 36.3 percent of boys ages 12 to 19 consumed the recommended amount of calcium.

Such data, and especially the poor calcium intake among adolescent girls, prompted the institute to begin a public information campaign called "Milk Matters" to educate health professionals, parents and children about the importance of consuming enough calcium, particularly from milk and other dairy products like yogurt and hard cheese, to protect bone health.

In this month`s American Journal of Clinical Nutrition, researchers from Cincinnati Children`s Hospital reported that adult women who consumed less than a glass of milk a day during childhood had flimsier bones and a twofold greater risk of fractures than those who consumed a glass of milk or more each day as they were growing up.

Dr. Connie Weaver, who heads the department of foods and nutrition at Purdue University, points out that "adolescence is a critical time to optimize bone health" because about half of an adult`s skeletal mass is accrued during the teenage years.

"Current calcium intakes of adolescents are well below recommended levels," Dr. Weaver said. "Studies indicate that four to five servings a day of calcium-rich foods are needed to optimize peak bone mass during adolescence."

An eight-ounce serving of a calcium-rich food like milk or yogurt would provide at least 300 milligrams of calcium. Comparable amounts can be obtained from calcium-fortified soy milk and orange juice and a cup of cooked collard greens. Many breakfast cereals are now fortified with calcium. And even some milks have added calcium.

Emerging research is showing that the importance of calcium goes well beyond bones.

Calcium helps to lower blood pressure in about one-third of people with hypertension.

Researchers at the University of Wisconsin showed that hypertensive women who took 1,500 milligrams of calcium a day, in addition to their medication, for four years experienced a significant drop in blood pressure, while those who took just medication experienced an overall rise in blood pressure.

Calcium also improves blood lipid levels. In a study at the University of Auckland in New Zealand, researchers found that a daily 1,000-milligram dose of calcium citrate increased protective H.D.L. cholesterol levels and lowered harmful L.D.L. cholesterol, a change that could reduce the rate of cardiovascular problems by 20 percent to 30 percent.

Although the role of calcium in cancer is still being investigated, the latest study, which followed 135,000 health professionals for 10 to 16 years, found that total calcium intake in excess of 1,250 milligrams a day was associated with a nearly 30 percent lower risk of developing cancer in the lower colon.

(http://www.nytimes.com/2003/01/07/science/07BRDD.html)

corekim@donga.com