...From the pages of Agricultural Research magazine
Boning Up on
Mineral intakes of Navajo children
| An unusual phenomenon draws the
attention of ARS nutritionist Judith G.
Hallfrisch. A recent study, published in the Journal of the American
Geriatrics Society, found Native Americans have denser bones than
Caucasians, yet they don't eat a lot of dairy foods. Hip and other bone
fractures are often the result of weak bones, caused by osteoporosis, a
degenerative bone disease. Nearly 10 million Americans suffer from
osteoporosis, which is responsible for 1.5 million fractures annually,
according to the National Institutes of Health.
"Osteoporosis is usually prevented by a combination of things, including
eating foodsparticularly dairy foodshigh in calcium and vitamin
D," says Hallfrisch, who is with the ARS Beltsville Human Nutrition
Research Center, in Beltsville, Maryland.
Genetic differences have been cited as an explanation for low fracture rates
among the largest group of North American Indians, the Navajo.
"Environmental and cultural practices may also play a role in the sturdy
bone structure of Navajo people," says Hallfrisch. "We think there's
something in their drinking water or food that's contributing to this unusual
occurrence. So, we're collaborating on a study with investigators at Utah State
University to assess how overall mineral intake is related to bone health and
other conditions in Navajos."
On the reservation, Navajos get their water from wells, springs, and taps, and
store it in barrels. After several trips to Navajo reservations in Utah,
Arizona, and New Mexico, Hallfrisch analyzed more than 100 water samples for
minerals. She found the average water intake of 2 liters a day can provide up
to 212 milligrams of calcium, 150 milligrams of magnesium, and 8 milligrams of
"The water is high in minerals because the ground is alkaline and has lots
of minerals. Although the Navajos don't eat much dairy, they are still getting
good nutrient amounts from their water," she says.
In addition, a colleague of Hallfrisch's at Utah State University analyzed the
contribution of juniper asha gray, finely ground powder traditionally
added to native dishesto overall mineral intakes in Navajo people.
Navajos burn juniper branches and grind them into a powder, which they add to
breads and traditional corn dishes.
"Juniper ash is rich in minerals that may also contribute to decreased
bone-related injuries," Hallfrisch says. "Total intake of these
minerals, which strengthen bones, including the amounts in water and juniper
ash, are much closer to dietary recommendations than diet surveys suggest, and
may partially explain low fracture rates."
As part of this study, Hallfrisch has been collecting samples of Native
American foods to evaluate their nutrient content. Unfortunately, she says,
intakes of younger Navajos are becoming closer to average U.S. diets, with high
soda intakes and few traditional dishes or dairy products.By
Weaver-Missick, Agricultural Research Service Information Staff.
This research is part of Human Nutrition, an ARS National Program (#307)
described on the World Wide Web at http://www.nps.ars.usda.gov.
Judith G. Hallfrisch is with the USDA-ARS Diet and Human Performance Laboratory, Bldg. 308, Beltsville, MD 20705; phone (301) 504-9061, fax (301) 504-9098.
"Boning Up on Navajo Food Habits" was published in the June 2001 issue of Agricultural Research magazine.