A Healthy Habit: Nuns Used in Medical Research

June 12, 2007 — -- Next time you take a calcium pill to stave off osteoporosis, or extol the health benefits of beer to your buddy at the bar, it's not the scientists in white lab coats you should thank — it's the sisters in the black habits.

Every year hundreds of Catholic nuns are weighed, measured, poked and prodded in the name of medical research.

In a study recently conducted by the Centre for Information on Beer and Health in Spain, 50 nuns drank a half-liter of beer every day for 45 days. Six months later they took 400 milligrams of hops, reported Reuters.

The study found that cholesterol rates fell by 6 percent in those sisters with high levels.

"We did it for the good of humanity," Sister Almerinda Alvarez told the newspaper El Pais.

Sister Almerinda's American counterparts, who have participated in studies on osteoporosis, Alzheimer's disease and other ailments, could not agree more.

Scientists believe nuns' unique lifestyles, free of sex and children, and the similar health conditions that nuns share with one another, make them an ideal group for broad scientific studies. And the nuns' willingness to volunteer for studies — some of which follow them for decades — is part of the reason why scientists like working with them.

"One of the major reasons we looked at nuns was because of their altruism," said David Snowdon, director of the Nun Study at the University of Kentucky's Sanders-Brown Center on Aging.

Altruism, Clean Living Make for Good Science

Snowdon's Nun Study, an effort to discover indicators for Alzheimer's disease, has tracked 678 members of the School Sisters of Notre Dame congregation.

In addition to their altruism, the nuns were chosen because Snowdon's team wanted to isolate factors in early life that may contribute to Alzheimer's disease, and the nuns' similar lifestyles made them a good control group — after the nuns took their vows, many aspects of their lives, including diet and access to health care, were the same for all of them.

The study initially compared the autobiographies of 93 nuns born before 1917 and written when they first took their vows in their 20s. The scientists found that those nuns who wrote more complicated sentences as young women were less likely to develop Alzheimer's in old age.

The researchers believe this may offer evidence early in life that indicates a likelihood of later developing Alzheimer's.

"We had a window into their early lives that we don't normally get once someone begins losing their memory," Snowdon said. "We could go back and look at the archives — histories, autobiographies, high school transcripts — and see a version of them 60 to 80 years before they developed Alzheimer's disease."

No Family, No Body Issues

The Religious Orders Study, conducted by David Bennett at the Rush Alzheimer's Disease Center in Chicago, has been studying Alzheimer's not just in nuns, but also priests and monks since 1993.

About 1,100 clergy members have volunteered to participate in the study and donate their brains for further research after they die.

"The clergy has a long history of volunteerism and contributing to the public good," Bennett said. "They have to be tested every year and donate their brain. One reason we asked is because we thought they would agree. They have no children, so there is one less hurdle when acquiring their organs."

Bennett said that aside from lower estrogen levels associated with women who have had children, nuns were pretty typical of women.

The Rush study has already yielded more than 100 published articles that have helped identify factors that contribute to Alzheimer's, including a link between the disease and a loss in body mass.

Between 1967 and 2000, Robert Heaney of the Creighton University Medical Center in Omaha, Neb., studied 200 nuns between the ages of 40 and 60. The Omaha Nun Study carefully monitored the nuns' diets over decades and made important discoveries about the benefits of calcium in preventing osteoporosis.

"Beginning in the '60s, we cast about for a population that would be stable," Heaney told ABCNEWS.com. "As society became more mobile and people more constrained by time, we knew we wouldn't find it in typical suburban housewives. Also, the recruiting was easy. We only needed to send letters to five mother superiors."

Sister Zita Marie Sharrow joined the study in 1979.

"Every five years we went to the hospital for eight full days for a very precise study of our input and output," she said.

Scientists closely monitored the nuns' diets to study the effects of calcium on bone density.

"I wanted to take part because it was a good thing that would help many people. It was never about what we would get out of it," said the now 77-year-old Servite nun.

The nuns interviewed by ABCNEWS.com say they did not receive payment for their participation.

Free of Sex and Kids

After taking their vows, nuns abstain from sex, so some studies have compared the health of childless nuns with women who have had children.

One study conducted by Gunhilde M. Buchsbaum of the Rochester School of Medicine found that despite what had widely been believed, women who had children were no more likely to become incontinent than childless women.

Other studies have found that nuns, and other childless women, are at increased risk for breast cancer.

In the 1970s, Pergonal, one of the first fertility drugs for women who were going to be artificially inseminated, was "made from the urine of postmenopausal women and widely believed, to boot, that they were postmenopausal nuns," said Richard Paulson, director of USC Fertility.

The urine of postmenopausal women is rich in hormones called gonadotropines. Today some fertility drugs are still made from the urine of postmenopausal women.