In May 2017, Daniel Jones, an obesity researcher at the University of Mississippi Medical Center, convened a group on both sides of the salt debate to explore the feasibility of a randomized controlled trial. “Over the last few years in the medical literature,” he said, “there has been ... ” He paused to look for the right words. “I’ll say, a more contentious spirit. It was bothersome to me to see people disagreeing in a disagreeable way.” Jones himself believes current data sufficiently support a link between salt and heart disease, but he thinks stronger evidence in the form a randomized controlled trial could provide the push for policies that limit salt in processed foods.
The groups ran through their research options. The best evidence linking salt intake and high-blood pressure comes from short-term feeding studies, where researchers prepare the meals for participants over several weeks. But it is far too expensive to feed participants for the years it takes for heart disease to show up. And frankly, how many volunteers would follow a bland diet for years?
So they considered people already on controlled diets. Nursing homes, they ruled out because many of the elderly have medical conditions that already require eating a certain amount of salt. The military they ruled out because the population is so young and fit that it would take too long for heart disease to show up. That left prisons.
This month, the group published an editorial in the journal Hypertension proposing to study low-sodium diets in prisoners. Jones says he is currently in discussion with a private-prison management company to conduct an initial pilot study. He wanted to publish the proposed research to spark a conversation on the myriad concerns—ethical and logistical—that come with conducting research in prisons.
There are reasons to be cautious about research in prisons, which has a long and sometimes ugly history. “Until the early 1970s,” wrote the law professor Lawrence Gostin, “R.J. Reynolds, Dow Chemical, the US Army, major pharmaceutical companies, and other sponsors conducted a wide variety of research on prisoners—a captive, vulnerable, and easily accessible population.” Some of the infamous experiments were at Holmesburg Prison in Philadelphia, where a dermatologist subjected prisoners to a suite of products including what became the skin-cream ingredient Retin-A . “All I saw before me were acres of skin,” the dermatologist reportedly told a newspaper reporter. “It was like a farmer seeing a field for the first time.”
The 1970s brought congressional hearings on protections for human subjects and the passage of the National Research Act, both of which were spurred by public outcry after the Tuskegee study. Prisoners are now considered a vulnerable population—along with children, pregnant women, and the mentally disabled—who required special protections in research. “Consent means something very different in the prison environment,” says Marc Morjé Howard, the director of the Prisons and Justice Initiative at Georgetown, whom Jones also consulted about preliminary ideas for the salt-intake study. Prisoners who participate in a study so they can get access to health care or because they believe they must do so to stay in the good graces of correctional officers may not be choosing freely.