By Janet Hunt
Driving down Second Avenue North on weekday mornings this winter, you may have noticed women at their cars packing picnic coolers that seem more appropriate for a July outing at Larimore (N.D.) Dam.
But noting that they are in front of the USDA-ARS Grand Forks Human Nutrition Research Center, you may realize that they probably are volunteers participating in human nutrition experiments. Odds are that you know someone who has volunteered for such studies, or you may have even been a volunteer yourself.
A total of 4,172 volunteers have participated since human studies began in 1976 at GFHNRC. That’s the equivalent of 8 percent of the current population of Grand Forks! Granted, they were not all local residents, as the research has included nationwide recruitment of volunteers willing to live with us for six months. And dietary information and blood samples have been collected from volunteers as far away as China.
But many of our volunteers are local, like the 20 women who are letting us control everything that goes into their mouths for 14 weeks and measure their blood, urine and calcium absorption. The study will expand our research finding that women absorb and retain their dietary calcium just as well from a high-meat diet as from a low-meat diet. In this study, we are testing whether calcium retention is further influenced by eating plenty of fruits and vegetables with the low-meat diet.
Although our scientists do what they can with experimental animals (usually rodents) and with cells in culture or direct chemical analyses of foods, it also takes human volunteers to learn how to solve human nutrition problems. For instance, to help address nutrient deficiencies in developing countries, agricultural breeders are selectively developing crop varieties that contain more nutrients such as carotene, zinc and iron. To screen different crop varieties, a laboratory procedure was developed to measure how well iron was absorbed by intestinal cells in a culture dish. These cell culture studies suggested that iron from light-colored legumes (such as great northern beans) was much better absorbed than from darker legumes (such as pinto beans).
To test human absorption, 13 volunteers from the Grand Forks community consumed the two different types of beans, carefully weighed and cooked with a minimum of other ingredients, as their breakfasts on two mornings. This allowed us to test how well the volunteers absorbed a specific iron isotope that had been added to the beans. Unfortunately, this test revealed that iron was poorly absorbed by the volunteers from both light and dark beans. But there was a silver lining: because of the efforts of these 13 volunteers, the research was refocused to find more successful ways to improve iron nutrition.
The volunteer spirit is alive and well in Grand Forks, and the conscientious efforts of the volunteers participating in human nutrition studies are the envy of researchers in larger cities. Although volunteers for this UND-approved research typically are given a monetary stipend for their time and efforts, my experience is that they take seriously the opportunity to contribute to new nutrition knowledge. Blizzards generally will not stop them, although some studies were interrupted by the 1997 flood. In the early stages of flood evacuation, several volunteers called seeking advice about how they could purchase groceries to substitute for the research diets.
One man called to explain that he temporarily was living in Devils Lake. Because he was regularly driving to work at the Grand Forks airport, he figured he still could pick up his food at the center and continue the study. Of course, most of the GFHNRC employees preparing his food also were being evacuated, so that study got postponed for a few months.
Another gentleman in the same study was invited back to participate in follow-up studies that extended blood measurements for another three years. When he also agreed to let us test his DNA for a common genetic mutation associated with excessive body iron, he smiled at me and joked “I’ll let you do anything but clone me.”
So, if at a party or restaurant you see volunteers bringing their own food in a cooler and eating every weighed crumb, realize that they are contributing in a unique way to improving our knowledge about healthy eating. Thanks, volunteers; we couldn’t do the research without you!