Today, people reach for foods fortified with important vitamins and minerals. Take orange juice. Not too long ago, consumer choice was pretty much limited to fresh or frozen. Now people can get their juice not only with or without pulp, but also with or without extra calcium—and even with or without supplemental vitamin D.
Such arrays of products fill a newly recognized niche in the consumer market, foods that appear to offer extra health benefits.
Alas, such nutrient-supplemented offerings have hardly made a dent in the nation's inadequate intake of several essential nutrients, including calcium and vitamin D. And that's why a team of nutritionists is now recommending that the federal government mandate the fortification of cereal-grain products, such as pastas and breads, with these two nutrients. The scientists note that approximately one-quarter of the calories in the U.S. diet derive from such grain-based foods.
Federal law already permits calcium and vitamin D fortification of food, these nutritionists note. Going the next step, to mandating these supplements in certain menu items, could have enormous impacts: huge reductions in the incidence of colon cancer and of fractures due to osteoporosis. Both conditions have been tied in numerous studies to chronically low consumption of calcium and vitamin D, a nutrient that helps the body use calcium efficiently.
Currently, the federal government requires that manufacturers enrich cereal-grain products with five nutrients—iron and the vitamins thiamine (B1), riboflavin (B2), niacin (B3), and folate (B9). The total cost to U.S. consumers of adding calcium and vitamin D to the list should be no more than about $19 million a year, Harold L. Newmark of Rutgers University and his colleagues report in the August American Journal of Clinical Nutrition. Conservatively, they calculate, this investment would spare U.S. consumers some $3 billion in direct medical costs from illnesses and injuries stemming from their inadequate intake of calcium and vitamin D.
We haven't learned
Nutritionists have been pointing out the benefits of diets rich in calcium for decades. Yet federal surveys show that after age 10, most people fail to get enough. By age 50—when women, in particular, begin losing bone because of hormonal changes associated with menopause, most U.S. adults get only around half as much calcium as the National Academy of Sciences' Food and Nutrition Board recommends.
That board sets the standards—which for many years were known as the recommended daily allowances or RDAs—for dietary needs by age and gender. The RDAs were developed as the minimum values needed to avoid serious disease. For calcium, those values were 800 milligrams per day through age 10, then 1,200 mg/d to age 25. After that, the RDA dropped back to 800 mg/day, except for women during pregnancy and while breast-feeding.
In 1997, the board issued a new set of guidelines for nutrients now known as dietary reference intakes, or DRIs. These new values were designed to address both serious vitamin and mineral deficiencies and daily intakes that promote good health.
These new values reduced the recommended calcium intake for children to 500 mg/d through kindergarten age, but through age 8, kids are still supposed to get 800 mg/d. From then through the teen years, the period of active bone growth, recommended daily calcium intake jumps to 1,300 mg/d. For ages 19 through 50, according to the DRIs, people need just 1,000 mg/d. Because men and women older than that face a rising risk of osteoporosis, their DRI bumps back up to 1,200 mg/d.
The DRI values may be better grounded in science than the older, simpler RDAs were, but the newer standards are a lot more confusing. That's especially true for people who weren't paying too much attention to their calcium intake in the first place. So, Newmark and his colleagues ask, wouldn't it make more sense to just pop a healthy portion of each day's recommended intake into the foods most people eat?
U.S. consumption patterns for vitamin D are even farther from the federally recommended values than calcium intake is. According to the National Academy of Sciences, most women get only about 100 international units (IU), which is around 2.3 to 2.9 micrograms, of vitamin D from their diets each day. That's only a fraction of the new DRIs, which span from 200 IU per day for people through age 50, to 600 IU per day for men and women over age 70.
In fact, Newmark argues, the dietary shortfall in vitamin D may be even more critical than that for calcium is. The rub: Fortifying food with vitamin D won't prove as easy as doing so with calcium because current law is more restrictive about food enrichment with the vitamin. Although existing law allows heavy calcium fortification of rice, corn meals, farina, vegetable products, macaroni, flours, and breads, it omits a similar enrichment go-ahead for vitamin D in flours and bread. Newmark and his coauthors recommend the law be amended to allow broader enrichment of food with vitamin D, but they say even existing provisions permit a first step toward better vitamin D intake in food.
The initial mandatory fortification of breads and corn-based products with niacin in 1942 wiped out pellagra, a deficiency of niacin that had killed thousands of people in the United States. More recently, the compulsory enrichment of cereal-grain-based foods with folate reduced by 25 percent the annual incidence of neural-tube birth defects (SN: 5/29/04, p. 349).
Under current law, calcium fortification of cereal grains could lead to an average 400-milligram daily increase in the mineral's intake across the U.S. population, Newmark's team has calculated. Some 350 mg per day would come from wheat products such as flour. Law would also allow enough vitamin D fortification of corn meal and pastas to add 50 IU to the average adult diet.
Based on epidemiological studies, these supplemental doses of calcium and vitamin D could easily cut colon cancer incidence by 30 percent, Newmark's team says, and reduce osteoporosis-related bone fractures among the elderly by about 20 percent.
Together, the two nutrients would add an estimated 6 to 10 cents to the cost of food per person per year—or collectively some $19 million. The team contrasts that amount with the annual savings of averting some 300,000 fractures ($2 billion) and preventing some 27,000 cases of colon cancer (more than $1 billion).
But Newmark concedes that these are just educated guesses, though they're based on a host of studies and analyses. What he and his colleagues would like is for the National Academy of Sciences or some other independent organization to convene nutrition experts to review and make recommendations about mandatory fortification of food with calcium and vitamin D.
Newmark says he's betting that such an assessment will confirm that a trivial investment in the food supply could yield huge economic and health dividends.
Harold L. Newmark
Susan Lehman Cullman Laboratory for Cancer Research
Department of Chemical Biology
164 Frelinghuysen Road
Piscataway, NJ 08854-8020
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