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Add calcium and vitamins to foods? The debate over fortification

August 15, 2004 1:08 am

ADDING CALCIUM and vitamin D to bread, pasta, cereal and other grains could prevent 27,000 cases of colon cancer and 300,000 broken bones from osteoporosis for a dime per American, say researchers.

But can you overdose on fortified foods? What are the real costs and benefits?

In some ways, the report in this month's American Journal of Clinical Nutrition raises more questions than answers.

It seems clear that Americans aren't getting enough calcium and vitamin D, and that this is causing diseases, but what is the best and safest solution to the problem?

Adding vitamins and minerals to the food supply is nothing new.

The U.S. government began adding iodine to salt in 1924. Since then, it has added vitamins A and D to milk and mandated "enriching" white flour with thiamin, niacin, riboflavin and iron, returning some of the nutrients lost when whole grains are transformed into refined ones.

Today, most Americans don't remember the names of the disfiguring deficiencies we now avoid by eating fortified foods: goiter, rickets, beriberi, pellagra. (Incidentally, whole grains, though they're not fortified, are naturally high in B vitamins.)

Most recently, in 1998, the U.S. mandated adding folate to enriched flour and cereal grains to help prevent birth defects. The following year, rates of a paralyzing defect called spina bifida dropped by 31 percent.

Even though adding folate helped many people, taking in too much folate in a day can mask a serious deficiency of vitamin B12, making it undetectable by blood tests even while people suffer permanent nerve damage.

For this reason, fortifying foods with folate alone was hotly debated; folate is important for pregnant women, while the elderly are more at risk for deficiency of vitamin B12.

Furthermore, young children are at higher risk of overdosing on fortified foods. National food surveys estimate that 20 to 30 percent of children under the age of 8 may exceed the safe upper limits for folic acid by eating fortified cereals, grain products and supplements, according to the American Dietetic Association's position papers.

A researcher at Purdue University says additional calcium and vitamin D won't cause problems.

"The upper levels for vitamin D are considered too low so we need not worry about this low level of fortification proposed," said Connie Weaver, professor and department head of foods and nutri-tion at Purdue University in Indiana. Weaver's research has been used to establish public policy, including the U.S. Dietary Reference Intake for calcium.

One of the authors of the fortification proposal says the British have added calcium to flour since the 1940s, and it helps reduce not just osteoporosis but also high blood pressure and lead poisoning in children. Paul Lachance, professor of food science and nutrition at Rutgers University, said he's been studying calcium for decades. "I was the guy who put calcium into Tang for the astronauts," he said.

Lack of vitamin D and calcium is far more common than overdoses, say Weaver and many experts.

One study at Massachusetts General Hospital showed that half of people admitted for surgery had low levels of vitamin D in their blood. The body needs vitamin D to use calcium to strengthen bones, and it also appears to reduce the risk of colon cancer, rheumatoid arthritis and multiple sclerosis. Some people who have fibromyalgia actually appear to have vitamin D deficiency, and after they take vitamin D long enough to replete blood levels, their pain vanishes.

Although it's hard to overdose on vitamin D from normal foods, it can happen from supplements or foods that are fortified improperly. Too much vitamin D can cause nausea, vomiting, poor appetite, depression, lethargy, high levels of calcium in the blood, kidney stones and irregular heartbeats.

Vitamin D is hard to come by in foods. The main natural sources of vitamin D are fatty fishes, such as mackerel and salmon, along with smaller amounts in egg yolks. Most people get vitamin D from fortified milk.

And although our skin can make vitamin D from being in sunshine, most Americans don't get enough sun (even Virginia is considered too far north to provide adequate sun for most people during wintertime). Those of us who are darker-skinned make less vitamin D. With the risk of skin cancer from too much sun, many experts recommend vitamin D supplements instead.

And while calcium is widely available in milk, cheese, yogurt and leafy green vegetables, most Americans don't meet guidelines for calcium after the age of 10, studies show. Over time, the body withdraws calcium from bones to make up the difference. The deficit doesn't become apparent until later in life, when many older women and men break hips or legs and lose their independence.

Some say that fortification doesn't make sense. "It is also easy and inexpensive to simply take a calcium and vitamin D supplement," said Shari Lieberman, a nutritionist in New York and author of "The Real Vitamin & Mineral Book."

Meanwhile, food manufacturers are already voluntarily adding calcium and vitamin D to a variety of foods, not just milk and cereal.

"I think you've probably seen some juices that are vitamin-D fortified," said Stephanie Childs, spokesperson for Grocery Manufacturers of America. "Companies are already doing it."

Busy Americans are buying $10 billion worth of fortified food each year, according to an industry report.

"This fortification can also give a false sense of security to people, so they don't even bother to clean up their diet," said Lieberman.

Eating less meat and more fruits and vegetables has been shown to reduce the risk of colon cancer. And for strong bones, we need more than just calcium and vitamin D: Magnesium, vitamin K and vitamin B12, among others, also play a role.

Some argue that Americans wouldn't need so much calcium to prevent osteoporosis if they didn't eat excessive amounts of protein, phosphorus, caffeine and sodium. In countries such as Japan where people eat less meat protein and less phosphorus, which is found in colas, rates of osteoporosis are lower than here.

Researcher Lachance wants the public debates to begin.

"We're trying to get the Food and Drug Administration to hold hearings on this," Lachance said, noting researchers have formally requested folate fortification since the 1940s to no avail. Perhaps publicity will be more effective.

"We're using a backdoor approach," he said. "They don't pay attention to us scientists."

JENNIFER MOTL, a registered dietitian, welcomes reader questions via her Web site, brighteating.com, or mailed to Nutrition, The Free Lance-Star, 616 Amelia St., Fredericksburg, Va. 22401.