Dr. David Relman investigates the secrets of the life sciences to help build a safer world.

The Stanford microbiologist and professor of infectious diseases has been named the next co-director of the university’s Center for International Security and Cooperation (CISAC). An adviser to the federal government on emerging biological threats, Relman believes his new role at CISAC will strengthen its core mission of making the world a safer place.

“There is a strong link between microbiology, infectious diseases and international security,” Relman said. “It is increasingly clear that the destabilizing effects of human population growth and displacement, environmental degradation and climate change are all mediated in part through the emergence and spread of infectious diseases. In addition, rapidly evolving capabilities of individuals in the life sciences around the globe make it increasingly likely that this science will be used to cause harm.”

Relman, the Thomas C. and Joan M. Merigan Professor at Stanford and chief of infectious diseases at the VA Palo Alto Healthcare System, has advised the U.S. government about pathogen diversity, biosecurity and the future of the life sciences landscape. He is a member of the National Science Advisory Board for Biosecurity (NSABB), chairs the Forum on Microbial Threats at the Institute of Medicine in Washington, D.C. and has participated in a number of studies for the National Academies of Science.

"David Relman is one of the nation’s top scientists exploring the mysteries of infectious disease, a thoughtful adviser to policymakers, and an extraordinary colleague,” said Tino Cuéllar, a Stanford Law School professor and the center’s co-director. “He will make tremendous contributions to CISAC's leadership as we expand our activities on public health and biosecurity while continuing our work on arms control and nuclear security."

Founded nearly three decades ago, CISAC’s mission is to produce cutting-edge research and spread knowledge to build a safer world. Now a part of the Freeman Spogli Institute for International Studies (FSI), the center has a tradition of appointing co-directors – one from the social sciences and the other from the natural sciences – to advance the center’s interdisciplinary mission.

Relman will take up the post in January, when Siegfried Hecker’s term concludes after having served as co-director since 2007. Hecker, a nuclear scientist and director emeritus of the Los Alamos National Laboratory, is one of the world’s foremost experts on plutonium, nuclear weapons and nonproliferation. He will remain at CISAC and continue to teach in the department of Management Science and Engineering.

“It has been a personal pleasure to work with Sig,” said Cuéllar. “He has been an enormous asset to CISAC.  He will continue to be a visionary leader on nuclear security and arms control issues throughout the world.”

Relman joined Paul Keim, acting chair of the NSABB, to address a CISAC seminar in March about their work in advising the government on the potential dangers of laboratory-engineered H5N1 avian influenza.

The advisory board had been asked to review two manuscripts that described the deliberate modification of the H5N1 avian influenza virus so as to be transmissible for the first time from mammal to mammal via a respiratory route. This provoked a debate in the scientific community about the risks of such work and whether the details of these experiments should be published – details that would enable anyone skilled in the art of virology and molecular biology to recreate these highly virulent and transmissible viruses. Some argued that the research could end up in the wrong hands. The board eventually recommended in a split decision that this research should be published.

“Life scientists need to be involved in discussions about the oversight of risky science and the responsible conduct of science, so that the potential benefits can be realized while the risks are minimized,” Relman said.

Relman will continue to run his research lab at the Stanford University School of Medicine and the VA Hospital in Palo Alto, where his focus is on the beneficial communities of microbes in the human body. He is president-elect of the Infectious Diseases Society of America and a member of the Institute of Medicine at the National Academies of Science. He received his S.B. in biology from MIT in 1977 and an M.D. from Harvard Medical School in 1982. He completed his clinical training in internal medicine and infectious diseases at Massachusetts General Hospital in Boston.

“The appointment of a life scientist who focuses on infectious diseases and biosecurity is an innovative step for our work in international security and cooperation,” said Gerhard Casper, president emeritus of Stanford University and director of the Freeman Spogli Institute for International Studies.

Relman tells a story that illustrates his passion for scientific discovery. On a routine visit to his dentist about 15 years ago, he brought along his own test tube. He asked the dentist to give him some plaque that he had scraped off Relman’s teeth. He wanted to study his own bacteria.

“As a clinician, I can tell you my colleagues were not looking for new microbes to worry about,” Relman said. “Some of them believed there might well be some really weird new microbes in soil or in the ocean, but that the human microbial ecosystem was something that we understood quite well. Of course – that was wrong.”

Using DNA sequencing technology, he has since discovered hundreds of new bacteria in the human body.

“Our ability to predict the next important technical or conceptual advance in the life sciences is miserable, as is our ability to anticipate how these advances will be used,” Relman said. “But we can at least hope to engage the scientific community and the general public in discussions about our goals and our understanding of risks – and how best to mitigate them.”

You’re in the supermarket eyeing a basket of sweet, juicy plums. You reach for the conventionally grown stone fruit, then decide to spring the extra dollar per pound for its organic cousin. You figure you’ve just made the healthier decision by choosing the organic product — but new findings from Stanford University cast some doubt on your thinking.

“There isn’t much difference between organic and conventional foods, if you’re an adult and making a decision based solely on your health,” said Dena M. Bravata, the senior author of a paper comparing the nutrition of organic and non-organic foods, in the Annals of Internal Medicine.

A team led by Bravata, a senior affiliate with Stanford’s Center for Health Policy, and Crystal Smith-Spangler, a Veterans Affairs physician fellow at the center, did the most comprehensive meta-analysis to date of existing studies comparing organic and conventional foods. They did not find strong evidence that organic foods are more nutritious or carry fewer health risks than conventional alternatives, though consumption of organic foods can reduce the risk of pesticide exposure.

The popularity of organic products, which are generally grown without synthetic pesticides or fertilizers or routine use of antibiotics or growth hormones, is skyrocketing in the United States. Between 1997 and 2011, U.S. sales of organic foods increased from $3.6 billion to $24.4 billion, and many consumers are willing to pay a premium for these products. Organic foods are often twice as expensive as their conventionally grown counterparts.

Although there is a common perception — perhaps based on price alone — that organic foods are better for you than non-organic ones, it remains an open question as to the health benefits. In fact, the Stanford study stemmed from Bravata’s patients asking her again and again about the benefits of organic products. She didn’t know how to advise them.

So Bravata, who is also chief medical officer at the health-care transparency company Castlight Health, did a literature search, uncovering what she called a “confusing body of studies, including some that were not very rigorous, appearing in trade publications.” There wasn’t a comprehensive synthesis of the evidence that included both benefits and harms, she said.

“This was a ripe area in which to do a systematic review,” said first author Smith-Spangler, who jumped on board to conduct the meta-analysis with Bravata and other Stanford colleagues.

For their study, the researchers sifted through thousands of papers and identified 237 of the most relevant to analyze. Those included 17 studies (six of which were randomized clinical trials) of populations consuming organic and conventional diets, and 223 studies that compared either the nutrient levels or the bacterial, fungal or pesticide contamination of various products (fruits, vegetables, grains, meats, milk, poultry, and eggs) grown organically and conventionally. There were no long-term studies of health outcomes of people consuming organic versus conventionally produced food; the duration of the studies involving human subjects ranged from two days to two years.

After analyzing the data, the researchers found little significant difference in health benefits between organic and conventional foods. No consistent differences were seen in the vitamin content of organic products, and only one nutrient — phosphorus — was significantly higher in organic versus conventionally grown produce (and the researchers note that because few people have phosphorous deficiency, this has little clinical significance). There was also no difference in protein or fat content between organic and conventional milk, though evidence from a limited number of studies suggested that organic milk may contain significantly higher levels of omega-3 fatty acids.

The researchers were also unable to identify specific fruits and vegetables for which organic appeared the consistently healthier choice, despite running what Bravata called “tons of analyses.”

“Some believe that organic food is always healthier and more nutritious,” said Smith-Spangler, who is also an instructor of medicine at the School of Medicine. “We were a little surprised that we didn’t find that.”

The review yielded scant evidence that conventional foods posed greater health risks than organic products. While researchers found that organic produce is 30 percent less likely to be contaminated with pesticides than conventional fruits and vegetables, organic foods are not necessarily 100 percent free of pesticides.

What’s more, as the researchers noted, the pesticide levels of all foods fell within the allowable safety limits. Two studies of children consuming organic and conventional diets did find lower levels of pesticide residues in the urine of children on organic diets, though the levels of urinary pesticides in both groups of children were below the allowable safety thresholds. Also, organic chicken and pork appeared to reduce exposure to antibiotic-resistant bacteria, but the clinical significance of this is unclear.

As for what the findings mean for consumers, the researchers said their aim is to educate people, not to discourage them from making organic purchases. “If you look beyond health effects, there are plenty of other reasons to buy organic instead of conventional,” noted Bravata. She listed taste preferences and concerns about the effects of conventional farming practices on the environment and animal welfare as some of the reasons people choose organic products.

“Our goal was to shed light on what the evidence is,” said Smith-Spangler. “This is information that people can use to make their own decisions based on their level of concern about pesticides, their budget and other considerations.”

She also said that people should aim for healthier diets overall. She emphasized the importance of eating of fruits and vegetables, “however they are grown,” noting that most Americans don’t consume the recommended amount.

In discussing limitations of their work, the researchers noted the heterogeneity of the studies they reviewed due to differences in testing methods; physical factors affecting the food, such as weather and soil type; and great variation among organic farming methods. With regard to the latter, there may be specific organic practices (for example, the way that manure fertilizer, a risk for bacterial contamination, is used and handled) that could yield a safer product of higher nutritional quality.

“What I learned is there’s a lot of variation between farming practices,” said Smith-Spangler. “It appears there are a lot of different factors that are important in predicting nutritional quality and harms.”

Other Stanford co-authors are Margaret Brandeau, the Coleman F. Fung Professor in the School of Engineering; medical students Grace Hunter, J. Clay Bavinger and Maren Pearson; research assistant Paul Eschbach; Vandana Sundaram, assistant director for research at CHP/PCOR; Hau Liu, clinical assistant professor of medicine at Stanford and senior director at Castlight Health; Patricia Schirmer, infectious disease physician with the Veterans Affairs Palo Alto Health Care System; medical librarian Christopher Stave; and Ingram Olkin, professor emeritus of statistics and of education.

The authors received no external funding for the study.

Michelle Brandt is the associate director of digital communications and media relations at the Stanford School of Medicine.

From Shanghai to São Paulo, people around the world are living longer than ever, challenging long-held ideas about retirement and well-established national retirement systems. Stanford health economists Karen Eggleston and Victor R. Fuchs offer an innovative view of the global aging phenomenon in an article published recently in the Journal of Economic Perspectives.

Drawing on a century of demographic data from 17 countries, Eggleston and Fuchs show that the share of increases in life expectancy realized after age 65 was only about 20 percent at the beginning of the 20th century but close to 80 percent by the dawn of the 21st century. Expected lifetime labor force participation as a percent of life expectancy is now declining. Eggleston and Fuchs share four interrelated responses to the economic and social challenges posed by this “new demographic transition:”

• Increase the retirement age.
• Encourage savings.
• Strengthen education.
• Emphasize healthy lifestyles early to ensure productivity in old age.

Eggleston is director of the Asia Health Policy Program at the Shorenstein Asia-Pacific Research Center. Fuchs is Henry J. Kaiser, Jr., Professor Emeritus, in Stanford’s Department of Economics and Department of Health Research and Policy, and a senior fellow at FSI and SIEPR.

Of the four policy responses the article proposes, is one especially critical?

Fuchs: The most important solution in terms of its potential impact would be people changing their attitudes toward retirement. This would mean people postponing retirement and saving more during their working years. If you work five years longer, for example, you would have greater savings and a shorter period of time when you would need the money.

Eggleston: We tend to think of the solutions as being interrelated. To address this longstanding and inevitable global demographic transition, organizations and policy structures need to support changes in individual behavior. In the case of the retirement age in the United States and European countries, policymakers need to change the many incentives that encourage people to retire younger.

What do you most hope policymakers will take away from the article?

Fuchs: We hope they will recognize the absolute need for individuals and organizations to plan for later retirement.

What are the special challenges faced by China and India, the world’s largest populations?

Eggleston: Longer lives in China and India contribute to improved human development, yet population aging also brings special challenges. China’s population is aging more rapidly than India’s and both countries need to invest more in the education and health of their young people, especially in poor rural areas.

In India, nutrition and education will help to reap a one-time boost to economic growth if the large cohorts of the working age population can be productively employed, while building a foundation for sustained improvement of living standards. China’s youth need to be as productive as possible to support the elderly while continuing to improve the national living standard.

The coming decade will be crucial in China, as the country transitions into a new economic phase and expands its fledging social protection system. The goal should be to ameliorate disparities and protect the vulnerable, while maintaining a financially sustainable and culturally appropriate balance of government and family responsibility for old-age support.

Instilling healthy eating and exercise habits in children may help prevent obesity later in life. But which kids most need such obesity-prevention efforts? A recent study by Jeremy Goldhaber-Fiebert and colleagues at Stanford's School of Medicine showed that this question is harder to answer than it seems. The study, published earlier this year in Medical Decision Making, found that targeting obesity prevention to small children who are overweight might not be effective. That's because a higher-than-normal weight at age 5 provides an accurate predictor of adult obesity only 50 percent of the time.

Goldhaber-Fiebert, an assistant professor of medicine and core faculty member of Stanford Health Policy, discusses the problem.

What does your paper tell us about the recent focus on childhood and adolescent obesity measurements?

Our study has two take-home messages. First, while childhood obesity is an important problem, solving childhood obesity alone will not solve future adult obesity problems. Second, addressing future adult obesity will require broader societal measures — not simply interventions focused on obese children.

It used to be that no one worried much if a small child was chubby; the doctor might say, "It's baby fat, he'll grow out of it." How has that changed?

In fact, our data show that many children still do "grow out of it." But our findings suggest that it is difficult to predict whether this will happen for a specific child. Consequently, efforts to help obese children must be connected to broader efforts to create healthy diets and habits for all children.

Childhood obesity is concerning both because it presents increased health risks for individuals while they are children and also because of the fear that it will translate into serious adult obesity-related health issues. Our analyses show that targeting children who are already obese is unlikely to be sufficient in addressing broader public health challenges of obesity in later childhood, adolescence and adulthood.

Are there other more promising screening criteria for chronic adult obesity instead of using a child's weight?

It really depends on the purpose of screening. Researchers have identified a variety of characteristics to predict a child's future obesity status — for example, easily observed measures like the weight of a child's parent as well as more complex measures such as their size at birth and the rapidity with which they subsequently grew and gained weight.

The challenge is to have a measure that both does not miss a substantial fraction of those who become obese later on and also does not falsely predict obesity for a large number of those who do not become obese as adults. The trade-off between these two types of errors depends on the seriousness of health implications of obesity and the costs of treating health conditions once they arise, as well as the health and economic costs of delivering preventive interventions to people who are identified as being at risk of becoming obese regardless of whether they become obese in the future.

What are some of the best potential approaches for reducing childhood obesity if the entire population is being targeted?

Given that many health-related habits are developed in childhood, efforts to create healthy eating and exercise habits in children would seem to be beneficial. But for most potential interventions, we lack evidence of their widespread effectiveness over a long period of time. Do reductions in obesity persist from childhood into adulthood? Do they lead to measurable improvements in health outcomes? We do not have answers to these key questions.

Food, beverage or sugar taxes and other manipulations to food prices or availability may be effective, but may also have unintended harms and certainly come at the cost of curtailing personal choice. Re-engineering the built environment or nudging people with various behavioral/economic mechanisms have garnered attention though, again, widely generalizable evidence on them is lacking. The problem deserves continued creativity and ongoing evaluation and testing.

Your paper focuses on which obese children will become obese adults, yet we are seeing a growing number of children experiencing type-2 diabetes and other negative health consequences of being overweight before they're even out of their teen years. Is adult obesity the best endpoint to focus on?

Obesity-related conditions of childhood clearly should not be ignored. What we are concerned about is the sense that people were conflating good care for children to deal with their shorter-term health needs (i.e., childhood obesity management to deal with childhood health issues) and the belief that such an approach might largely solve the broader adult obesity issues. Addressing childhood obesity is still important even if it does not fix adult obesity and its deleterious health consequences.

Erin Digitale is the pediatrics writer for Stanford School of Medicine's Office of Communication and Public Affairs.