A recipe for research
It takes patience, sacrifice, and lots of food to figure out whether something is really good for you.
Eric Evans savored one last slab of steak.
"I knew that was going to be it for a while," he said.
Evans, a financial adviser by trade, was about to plunge into the world of diet and nutrition research at Tufts University, bellying up to the table in the name of science. For six months, three times a day, he would eat exactly what somebody else told him to eat -- not a morsel more, nor a crumb less. And certainly no T-bones.
This is the realm of research that asks: Can protein in chicken really help your heart? What about hibiscus in tea -- can it lower your blood pressure? And just how low can you go on your calorie count and stay healthy and happy?
Nutrition research generates headlines, sales, and controversy. Witness two Stanford University studies in the past month. They were big news: One showed that garlic does nothing to reduce cholesterol. The other concluded that the low-carbohydrate Atkins diet took off more weight than the ultra-low-fat Ornish plan.
Of course, previous studies suggested the opposite, showing that eating lots of garlic is great for health, that the Atkins diet isn't any more successful long-term than other diets, and that the Ornish plan, followed carefully, can add years to your life.
Casual consumers of science are frustrated by this waffling; researchers are frustrated by how difficult it is to come to any nutrition conclusions at all.
Once, nutrition research meant taking a few ingredients and performing some lab tests. Or it involved looking at who did or didn't have a particular disease and what they did or didn't eat.
Now, gold-standard studies into food and its effects on our health require culinary mastery rivaling anything whipped up by a five-star restaurant, with dietitians spending months perfecting research menus that are both palatable and scientifically sound. (That means, for instance, not including too many olives or too much tarragon. People, it turns out, don't want olives and tarragon every day.)
Then there are the volunteers. They must pledge to never indulge their weaknesses and to always clean their plates, and, along the way, yield samples of blood, stool, or urine to measure the consequences of a particular vitamin or a whole diet.
"All of a sudden, you can't grab your favorite food anymore. They hate us because we did that to them," said Helen Rasmussen , a gregarious dietitian at Tufts whose job is to make science tasty. "I ask them how they respond to nagging from their mother -- at least they appreciate the warning."
Typically, the studies begin with a well-informed hunch. Researchers might know, for instance, that a certain nutrient has been shown in the lab or anecdotally to provide a health benefit.
"I translate the protocol into real food, something that the subjects can eat, can enjoy, and with portion sizes that are reasonable," said Evelyn Lashley , a research dietitian at the US Department of Agriculture's Human Nutrition Research Center in Beltsville, Md.
Sometimes, that means serving a side dish of reality to researchers.
Take the Tufts scientist who was examining the power of prunes. He wanted to serve volunteers 17 or 18 prunes. In one sitting. In a staff meeting, most colleagues lauded the proposed study. "Then, they got to me, and I was the skunk at the garden party," Rasmussen recalled.
To prove her point, she made him try his own prescription. "He went home. He said he couldn't go too far way from the bathroom."
When planning their research, scientists even take into account the vagaries of the calendar.
"Down here," said Marlene Most , a researcher at the Pennington Biomedical Research Center in Baton Rouge, La., "Mardi Gras is a big deal, so we look at when Mardi Gras is so people can be off, because we know during holidays people probably aren't going to be compliant."
After designing a menu and settling on a schedule, researchers embark on the hunt for humans amenable to spending weeks or months following a prescribed diet. There are inducements: Depending on the duration and complexity of a study, volunteers receive a stipend of several hundred to a few thousand dollars. And then there's all that free food.
Still, study recruiters are assiduous in explaining the rigors and requirements of the research, said Alice H. Lichtenstein , director of the cardiovascular nutrition lab at a USDA-funded research center towering about the Chinatown medical campus of Tufts.
"We really try to talk about the trials' tribulations," Lichtenstein said. "Some people don't anticipate ahead of time how much they enjoy their normal food routine. If a major part of their social life is going out with friends to eat, then this kind of study is probably not going to be for them."
Right now, Lichtenstein is examining whether eating specific proteins -- found, for example in chicken, soy, or fish -- can protect the heart. Participants in that study pick up all their food three times a week from a bustling kitchen, lugging home precisely measured portions, with instructions to eat the food from the container it's served in and to even use water and a scraper to make sure they consume any remnants in the bowl.
In the Stanford garlic study, researchers cooked up 30,000 sandwiches that they served to 200 volunteers over six months. Some people ate garlic-laced sandwiches nearly every day -- portobello on focaccia, salmon patties, vegetable patties, and grilled eggplant. Others ate the same food but without the garlic. In the end, the garlic had virtually no effect on cholesterol levels.
In the study comparing four different diets, including Atkins and Ornish, volunteers made their own food after attending classes conducted by a dietitian. But most of the pounds were shed in the first six months of the study, suggesting that volunteers may have begun straying from the diet as time wore on.
"That was part of our question, how would these things work in the real world?" said Christopher Gardner , a Stanford nutrition researcher who presided over that study.
But despite the study's limitations, lots of people will decide what to eat today because of what they heard about that study, published in the Journal of the American Medical Association .
"It's frustrating sometimes," Gardner said. "The public says, 'Oh, you scientists can't agree. God, you say, garlic yes one day, no the next.' It's often that it's a different question asked a different way."
Evans, who participated in a study of restricted-calorie diets, said he was motivated by a desire to peel away the hype from diet and nutrition claims.
"You get so many mixed messages from different headlines and different studies that I wanted to get to the background truth of it," said Evans, 41, who lives in North Reading.
Evans swears he was faithful to his high-fiber, high-protein diet. And while the scientists would like to rely on the word of their subjects, they don't.
By occasionally adding small amounts of harmless chemicals to food, researchers can use urine tests, for example, to catch cheaters. "If we put it in food and you eat it, we get it back," said Dr. Edward Saltzman of Tufts.
And what if there's too much of a certain substance, say, sodium?
"That's usually because you've gone across the street to
Stephen Smith can be reached at firstname.lastname@example.org. For information on becoming a research volunteer at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, please call 1-800-738-7555 or go to http://hnrc.tufts.edu/studies/.