A little packet of "sprinkles" may help millions of people who suffer from iron deficiency -- which the World Health Organization calls the most common nutritional disorder in the world. The WHO estimates that as many as eight out of ten people may not be getting the iron they need, with children in developing countries especially at risk.

Traditional ways of getting enough iron in the diet all have their drawbacks, leading a Canadian researcher to develop the Supplefer sprinkles -- a powdered form of iron and other nutrients that can be sprinkled onto food.

"There may be as many as 750 million children around the world with iron deficiency and iron deficiency anemia," says pediatrician Stanley Zlotkin, the University of Toronto professor who created the iron sprinkles. "In fact, the experts say that this is probably the last of the major problems that is yet to be solved."

The body doesn't need a lot of iron, and a balanced died should provide enough. But Dr. Zlotkin notes that foods that contain iron can be relatively costly. "For example, meat, fish and poultry are great sources of readily bio-available iron," he says. "But for many individuals in the developing world, of course, these foods are extremely expensive."

Adults who don't get enough iron get tired more quickly. Pregnant women need extra iron to protect their health and the health of the fetus. But, children are at the greatest risk -- particularly in the first two years of life -- because a lack of iron impairs brain development.

As a result, says Dr. Zlotkin, "if you have iron deficiency you don't do as well in school, you don't get good jobs, and you don't earn as much money. So the effects of iron deficiency are marked long-term effects." Many economists believe that widespread iron deficiency among youngsters can have a major impact on a nation's economy.

One low cost remedy is for food processors to add iron to their products. "For example, in Vietnam currently there is a program of fortifying soy sauce with iron," says Dr. Zlotkin. "Soy sauce is a great food to fortify because it's inexpensive, most people in Vietnam use soy sauce, and when you add iron to the soy sauce it actually doesn't change the taste or the color of the soy sauce." The problem is, children may not get enough of the fortified food.

Another approach is for people to take an iron supplement. Because children don't like to swallow pills, the alternative for them is an iron-enriched syrup. But the syrup has a tendency to stain teeth, and children object to its strong metallic taste. In addition, syrup is not very cost effective, and it can be difficult for parents to give their kids the proper dose.

That's where Dr. Zlotkin's sprinkles come in. He "micro-encapsulates" iron and other nutrients in a neutral food product to mask the taste, and then puts it in a fine powder form. "If you can imagine what flour would feel like, that's sort of what it feels like," he says. "And it looks like powder with some speckles of pepper in it."

The mixture is distributed in a little packet called a sachet, which provides the exact amount needed to meet a child's daily requirement of iron -- all at a cost of three cents or less per day. The sachets also include vitamin C, which actually enhances iron absorption, plus vitamin A, zinc and folic acid.

In new research published in the journal PLoS Medicine (25 January), Dr. Zlotkin and his colleagues report successful trials of sprinkles in West Africa -- where the product was at least as effective as other iron supplements, and where parents using the sprinkles reported a high level of satisfaction. Up until now, they have been distributed through UNICEF and through private groups such as World Vision and Helen Keller International. Pakistan and Bangladesh are among the governments that have programs to supply sprinkles.

The challenge, Dr. Zlotkin writes in the new paper, will be to expand distribution to all the children who are not now getting enough iron.