Recruits eat all kinds of stuff for USDA study

It's breakfast time inside Building 308, and a group of volunteers aged 22 to 68 have just ingested their treatments -- which is to say they've eaten bowls filled to the brim with delicately sliced purple carrots. Those who ate raw pieces of the vegetable, whose maroonish skin conceals an orange interior, are having a little more trouble swallowing than those who ate them cooked.

"Think about how your stomach would feel if you ate raw carrots for breakfast," said Sylvia Stevens, a 50-something volunteer from Lanham, Md., in an attempt to describe her subdued state as she lounges with her husband and others in a room outfitted with plaid couches, a television, magazines and plenty of board games to keep them occupied.

As part of a study administered by the Beltsville Human Nutrition Research Center in Maryland, 12 purple-carrot volunteers had to spend 12 consecutive hours in Building 308, eating under the scrutiny of the affectionately nicknamed "food police" and getting their blood drawn every half-hour.

They did this one day a month for three months.

To help scientists discover how the body absorbs anthocyanin, the nutrient that produces the purple color found in the specialty carrots and also in some berries, the volunteers drove through the U.S. Department of Agriculture's 7,000-acre Beltsville Agricultural Research Center, past cows grazing on expansive pastures speckled with government buildings.

The volunteers were well-versed in purple carrot, ready to discuss how the botanically clever Dutch, in the name of national pride, transformed the original carrot -- which was indeed purple -- into an orange-skinned hybrid to match their national color about 400 years ago. The volunteers were also aware that the chemical that makes the veggie's purple coloring may reduce the risk of cancer and cardiovascular disease.

No caffeine, alcohol

Aside from consuming a small pile of carrots to help scientists monitor whether humans absorb enough of the nutrient to reap its purported benefits, study volunteers also had to give up caffeine, alcohol, vitamins and dietary supplements for two days before their stints in Beltsville, Md. During that period, they ate only meals prepared and methodically weighed by research cooks, dietitians and other nutrition center employees.

Although this was one of the least stringent of the center's recent studies, not everyone willing to make these dietary sacrifices got the chance to trade their breakfast cereal for purple carrots. Scientists chose relatively healthy people of all ages who had normal blood levels, veins that "bleed well" and the ability to keep a catheter in for 12 hours. They ruled out picky eaters and those with allergies or major health problems.

As a rule, scientists in Building 308 assemble diverse groups of volunteers, but they sometimes have to make concessions -- such as in the ongoing "Smokers' Tea Study," which looks for adult male smokers who can be counted on to show up at the facility twice a day for several months at a time and eat only the food prepared at Beltsville.

Recent studies have featured such products as black tea, grain alcohol, wine, barley, tomato juice, watermelon and kale, all of which had to be consumed in significant quantities to enable scientists to study their effects.

The lack of restrictions in the purple-carrot study made it attractive to repeat study volunteers, who listed as their reasons for spending so much time in Building 308 the opportunity to eat a healthy diet free of charge, contribute to science research and get paid $500 in the process. Frequent study volunteers, many of whom live or work near the Beltsville campus, are reluctant to say that money is their sole motivation.

Research center officials assert that paying people to "volunteer" for such testing is not unethical, but rather something that is necessary to gather a sufficiently diverse group. Federal rules mandate that volunteers be compensated in some form. Were the payoff solely free medical testing and information, scientists say, volunteers would probably represent a skewed sample of the population, such as those who choose to participate in a heart study because a family member died of a heart attack.

"Even if you count in how much money you're being paid, you still have to have some kind of altruistic motive," said Karen Spears, Beltsville's human studies coordinator. "You really have to be someone who wants to contribute to the greater benefit of society, because you're not getting paid as well as you would if you spent the time working in a job."