BY MARY ANN LITTELL
Calcium acts as a shield against lead
"Drink your milk. It's good for you."
You've heard these words since you were a child, along with the reasons why. The calcium in milk builds strong bones and healthy teeth and prevents osteoporosis when you're older. New findings indicate it may even prevent hypertension, protecting against heart attacks and strokes.
As if those reasons aren't enough, there is now another compelling reason to drink your milk. Increasing calcium intake may dramatically reduce the risk for lead poisoning, according to a new study from UMDNJ-New Jersey Medical School.
"Lead is everywhere in our environment," says John D. Bogden, PhD, of the Department of Preventive Medicine and Community Health. "But the risk of exposure is greatest in urban areas, where many older homes and apartments have layers of lead-based paint."
"Calcium prevents the absorption of lead in the gastrointestinal tract, so it never even enters the bloodstream," says Bogden. "The more calcium you have in your diet, the greater your protection against lead poisoning."
In spite of many efforts to promote calcium and dairy products, the calcium intake of the US population is actually on the decline. To provide other food sources of calcium, Bogden and his fellow researchers, Donald B. Louria, MD, and James M. Oleske, MD, advocate fortification of non-dairy foods. "We've been fortifying salt with iodine for years, so no one has to worry about getting enough iodine. Why not do the same thing with calcium?" asks Bogden.
Some calcium-fortified fruit juices and cereals are already available. The researchers suggest fortification of more of them, and baked goods and bottled water as well. "Fortification of baked goods, including bread, cookies, and cake, would greatly boost calcium intake. These foods are mainstays in the diets of most children, who are at greatest risk for lead poisoning," says Bogden.
Environmental lead exposure has long been a cause for concern, particularly among children under the age of three. High levels of lead in children have been linked to permanent damage to the central nervous system, reduced intelligence and aggressive behavior. So great are the hazards of exposure that New Jersey physicians are required, through legislation passed last year, to screen all children for lead poisoning.
Despite these findings, new calcium guidelines released in September 1997 actually reduced the RDA (recommended daily allowance) for children under the age of three - the very group at highest risk. The new recommendations call for 210 mg for babies up to six months of age, 270 mg for children ages 6 months to 1 year, and 500 mg for children ages 1 to 3.
"A few hundred mg of calcium is not enough to protect children from lead in the environment," says Bogden. He recommends that children from 1 to 3 years of age get at least 500 mg a day, and preferably more. According to the new guidelines, 4- to 8-year-olds need 800 mg, 9- through 19-year-olds need 1,300 mg, adults from 19 to 50 need 1,000 mg, and those over age 50 need 1,200 mg a day.
These calcium goals are best met through a diet containing plenty of low-fat or non-fat dairy foods. Two glasses of milk a day provide 500 mg of calcium. Adding other dairy products to the diet boosts calcium intake even more. For example, a slice of Swiss cheese on a turkey sandwich adds about 250 mg of calcium. A tablespoon of parmesan cheese sprinkled on a Caesar salad yields an extra 75 mg of calcium. Many vegetables, including broccoli, spinach, kale, green beans and squash, also contain calcium.
Supplements are another source of calcium, but should not take the place of foods. Some supplements were recently found to contain small amounts of lead, which most manufacturers have readily agreed to remove. Supplements come in different forms, to suit different preferences. Some of the most common supplements are:
Calcium carbonate (Tums, Caltrate).
Least expensive and most widely available. Particularly effective in reducing
lead absorption. Highly concentrated so fewer tablets are necessary. Should
be taken with meals. Can cause constipation.
Calcium citrate (Citracal).
Less concentrated, multiple doses are necessary. Does not have to be taken
with meals.
Calcium phosphate (Posture).
Also less concentrated, requiring multiple doses.
Because calcium interferes with the absorption of other metals, including iron and zinc, those increasing their calcium intake should be sure to receive enough of these minerals in the diet.
Calcium is an excellent preventive measure, but not a cure-all, warns Bogden. Reducing exposure to lead is also very important. Calcium will reduce but not completely prevent the accumulation of bone lead with age, nor will it reverse damage to the central nervous system. It also won't prevent lead absorption through inhalation of paint dust and other sources of airborne lead. It is only effective in limiting absorption of lead that is ingested.
Now, drink your milk...and on the side, why not have a big wedge of creamy Brie or a chunk of Vermont cheddar?
