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Teen-agers and the calcium crisis.

TEEN-AGERS AND THE CALCIUM CRISIS

Kathy G., a biology major at theUniversity of North Carolina at Chapel Hill, noticed an interesting classified ad in the campus newspaper, the Daily Tar Heel: "Needed: college women between 18 and 22 for bone study." A subject in a research study--that would look good on her resume. She made an appointment.

Two days later, Kathy was interviewedby Dr. John Anderson, a graying, soft-spoken processor of nutrition in the university's schools of public health and medicine. She learned she was taking part in a first-of-its-kind, ongoing study of the eating habits and bone health of 1,000 college women. Thus far, more than 600 had been studied.

Dr. Anderson, a specialistin calcium research for 25 years, took careful notes on Kathy's dietary history back to her seventh-grade year. Some of his questions concerned her calcium consumption.

"Kathy, why did you'turn off' milk when you entered junior high?" Dr. Anderson asked.

Kathy shrugged. "Milkseemed babyish. Most of the kids drank soda with their meals. So I did, too. And I got in the habit."

"What about icecream? And hard cheese--like Swiss or Cheddar?"

"In the ninth grade,"Kathy said, "my friend Julie and I went on a diet. Ice cream and cheese were definitely on our 'no-no' list."

"And are they still?"

She grinned. "Having agood figures matters even more than ice cream. And I love ice cream!"

"Yogurt?" Dr. Anderson asked.

"Yuck!" Kathy said.

Later, in the student health center,her weight and height were measured, and skin-fold measurements were taken to estimate her body fat. (Kathy came out flabless.) As a final step, she sat before a single-photon bone densitometer: a heavy, compact, portable machine, which, the technicial explained, would measure her bones and print out a computerized analysis that included her bones' calcium content and a picture showing the pattern of their minerals.

Two of Kathy's bones were measured:the spongy bone in her wrist and the compact bone in the middle of the shaft of her forearm (the radius bone). These two are typical of the most important bones in the body. "They can be used as general markers for the whole skeleton," the technician told Kathy.

Dr. Anderson came in and lookedat the computer print-outs.

"Well, Professor, how are mybones doing?" Kathy asked.

She was unprepared for his answer. "I'mafraid you fit into the lower quarter of the students we've measured," Dr. Anderson said.

"What? But--why?"

"Thus far," Dr. Anderson said,"our study has found that in general those girls--like you--who have poor bone-mineral content and bone density are the same girls who have a low calcium intake." He looked more closely at Kathy's print-outs. "It's really quite startling to actually see the results of low calcium consumption showing up so clearly in bone-density pictures at such a young age."

Then he added: "Don'tlook so glum, Kathy. The good news is that you found out in time. Start drinking milk again--low fat, if you're still on a diet. Three glasses a day plus some cheese should do it. And, especially if you couple your daily calcium intake with some exercise, such as jogging, dancing, biking, even brisk walking, your bone picture should normalize."

"How long will ittake?" Kathy asked.

"That research hasn't been doneyet," Dr. Anderson said. "But we do know that teen-age girls and young women who don't build up their calcium bone banks may put themselves at real risk of osteoporosis--a painful, crippling bone disease with no cure, a disease that his one in every four American women after menopause."

"Professor," Kathy said, "I justbegan to love milk again!" Kathy's case is, unfortunately, all too typical.

From 1976 to 1980, the NationalCenter for Health Statistics conducted the most extensive health and nutrition survey in this nation's history. Doctors examined more than 20,000 people in mobile vans that traveled throughout the country. The people surveyed were randomly chosen in advance by the Census Bureau. One of the most striking finding was the low calcium ratings of teen-age girls. Indeed, the lowest comparative ratings of any nutrients were those concerning the vital mineral calcium.

The official Recommended DietaryAllowance (RDA) of calcium for teens is 1,200 milligrams per day. Only one other group has an equally high RDa: pregnant women and nursing mothers, who are, after all, "eating for two." (Pregnant adolescents have the highest RDA of all: 1,600 mg daily.) In the national survey, girls aged 12 to 17 averaged only 692 mg. The calcium "score" for 18- to 24-year-old women was even worse. Almost half our teen-age girls are consuming less than half the calcium they need--putting them in an automatic "risk" category for osteoporosis when they reach their later years.

Like Kathy, teen-agers--especiallygirls--often decide milk is not "cool." They switch to carbonated soda as their mealtime drink. "These sodas," Dr. Anderson says, "not only ratehigh in the empty-caolorie category, but in many cases they have a high phosphate content, which may, in turn, have adverse effects on bone health by interfering with calcium absorption. Teen-agers," he stresses, "need more calcium than any other age group."

Dr. Morris Notelovitz, a calciumexpert and the author of Stand Tall! The Informed Woman's Guide to Preventing Osteoporosis, the first book on osteoporosis for the general public, puts in this way: "If we don't have sufficient calcium, then we don't have solid bones. Calcium makes up a large part of the minerals in bone, and it is calcium crystals that give your bones their strength, hardness, and rigidity. The adolescent years are the most critical bone-building years. Between 45 and 55 percent of an adult's bone structure is formed during the adolescent growth spurt."

Joseph Zanga, M.D., chairman ofthe American Academy of Pediatrics School Health Committee, adds: "In adolescence, children experience their final push to adult size, with as much as five inches growth per year for several years, beginning at puberty. Good nutrition, including adequate calcium intake, is therefore essential during this period."

But the growth push is only half theage equation that makes adequate calcium intake so vital during the teen years. The other factor is the importance of builting a good calcium "bank balance" in the bones. "Though not many people realize it," Dr. Anderson says, "when you reach the decades of the 30s and 40s, no matter what, your bones start losing calcium. And they continue this calcium drain for the rest of your life. If you don't have a good calcium bone reserve built up, you're far more likely to develop osteoporosis and/or other bone diseases in later life. It is, therefore, imperative that teen-agers pay far more attention to the intake of calcium."

Until now, calcium researchers, nutritionists,pediatricians, and others concerned about the low calcium quotients of teens and young women had comforted themselves with the assumption that at least preteens still obediently abided by their mothers' dictum: "Drink your milk. It's good for you." And milk 'n' cookies were assumed to be a ritual for kids returning from school. However, another first-of-its-kind, ongoing study has yielded sobering findings on this point. The study is being conducted by Gary Chan, M.D., who has been involved in calcium research for a decade. To date Dr. Chan and his two-person team--a nutritionist and a research nurse--have taken dietary histories of more than 100 children. The results are striking:

* Girls -- particularlythose from ages 11 to 16--had significantly poorer nutrition than boys of the same age. "The drop in calcium was one of the most notable elements because, even at this early age, many girls tend to substitute soft drinks for dairy products," Dr. Chan says.

* Almost 80 percent ofthe girls and 50 percent of the boys over age 11 were consuming less than the Recommended Dietary Allowance of calcium. About 30 percent of the boys and girls younger than 11 were below the RDA.

*From ages 3 to 11, nutritionscores were good for most boys and girls. But the study showed that young children getting 1,000 mg or more of calcium a day had a significantly better bone mineral content than children taking just the RDA for preteens: 800 mg a day.

Dr. Chan's conclusion: "Morechildren should be drinking more milk, more often." He adds, "As a pediatrician, I'm concerned that poor bone health established in childhood can lead to adult osteoporosis. Our studies indicate that the calcium RDS for children should be raised from 800 to 1,000 milligrams per day."

But even if calcium input is increased,how much will be retained?

The first study of calcium rententionin teen-age girls was conducted in 1985 by Velimir Matkovic, M.D., Ph.D., of the Department of Rehabilitation Medicine at the University of Washington School of Medicine in Seattle. Dr. Matkovic's interest in the calcium question started in his homeland, Yugoslavia, in 1972. As a research assistant in the Department of Mineral Metabolism of the University of Zagreb Faculty of Medicine, he led one of the largest epidemiological calcium-bone-mass investigations in the world. More than 2,000 people were studied. Half lived in the cattle-raising region of Podravina, where virtually all residents drank milk with their meals and consumed ample amounts of cheese. Their calcium intake averaged 1,200 mg a day throughout their lives. The other 1,000 people lived in Istra, a rural district that raised mostly crops rather than cattle. Their daily calcium intake averaged only 500 mg.

"The high-calcium group had significantlyhigher bone mass than the low-calcium group," Dr. Matkovic says. "Furthermore, the incidence of hip fractures was much higher in the low-calcium group. Our main conclusion was that calcium consumption is probably more important during the period of rapid bone growth--ages 10 to 20--than at any other time in life. During this period, high calcium intake can contribute to osteoporosis prevention."

Calcium research continuedto be Dr. Matkovic's prime interest in Yugoslavia, England, and, since his arrival in 1984, the United States. His latest study deals with calcium retention. His first subjects were 20 healthy teen-age girls. He hospitalized them, two at a time, at the University of Washington Clinical Research Center. The girls watched television and movies on a VCR, were visited by tutors, did their homework--and ate only what was given to them. No smuggled-in snacks, no late-night "pig-outs."

The study measuredtheir calcium balance: intake versus output. Calcium input started with a mere 300 mg a day--a typical amount in a non-dairy-food diet. Then the input was increased to 500 mg, 700 mg, 1,200 mg, and finally 1,600 mg a day--all within a two-week period. Different girls were on different calcium intakes. The "output" was carefully traced in the girls' feces and urine.

The study found a direct relationshipbetween intake and retention of calcium. "Apparently, at this age young skeletons have the ability to store extra amounts of calcium--which may not be true at later ages," Dr. Matkovic said. "The findings suggest that a higher-than-RDA calcium intake during teen-age years can contribute to a higher peak bone-mass formation. And this, in turn, may have a beneficial impact concerning osteoporosis later in life."

Robert Recker, M.D., of CreightonUniversity of Omaha, Nebraska, is one of the nation's foremost calcium researchers. The author of more than 40 papers on calcium's effect on bone, he is currently involved in a five-year study of the calcium intake and bone condition of women ages 19 to 25. He notes: "Since the calcium needs of teen-agers and young women is such a crucial matter with a lifelong impact, it is remarkable, indeed, that it has been so underrecognized on the research front. The three important ongoing studies of Anderson, Chan, and Matkovic are the first to alert us to the sobering early warning signals."

Dr. Recker points out that thecraze for dieting may have a dangerous impact on the calcium front: "Teen-age girls think they are slimming successfully by drinking diet soda, and they shun skim milk, which is not fattening and is replete with valuable nutrients. A glass of skim milk contains about 300 mg of calcium, as well as lactose, a sugar which aids in the absorption of calcium. In addition, 98 percent of milk sold in the United States is fortified with vitamin D, which also aids in calcium absorption. Milk--skim, low fat, or regular--also contains vitamin A, riboflavin (B.sub.2.), many important minerals such as magnesium and phosphorus, and high-quality protein."

Another leading calcium researcher,Dr. B. Lawrence Riggs of the Mayo Clinic, notes that, despite calcium's RDA for teens (1,200 mg) being higher than that of any other age bracket, "it is not difficult to meet. Three dairy products a day and you've got it. Two or three glasses of milk, a scoop of ice cream, a serving of yogurt, and Swiss or Cheddar cheese. Additional calcium can be obtained from other food products, including sardines with bones, broccoli, kale, collard greens, and that staple of the modern health-food store, tofu."

Dr. Riggs adds, "In addition, increasedphysical activity should be encouraged, and bone toxins, such as cigarettes and heavy alcohol consumption, should be eliminated."

Dr. John Anderson sums up theteen calcium crisis in these words: "A majority of today's teen-age girls are seriously shortchanging their skeletons. They--and their parents--must remember that a low intake of calcium during adolescence can limit bone growth and predispose young women to decreased bone mass, which, in turn, may contribute to osteoporosis in later life. To tabel milk as "uncool' is to look down your nose to spite your body."
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Author:Mann, Peggy
Publication:Saturday Evening Post
Date:Apr 1, 1987
Words:2251
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