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.

Countries throughout the world increasingly share similar health policy challenges such as healthcare and insurance reform, rapid demographic change, and high rates of chronic diseases like diabetes. The Asia-Health Policy Program (AHPP) is one of several Stanford organizations seeking solutions to major global health issues through a comparative study of the health policies of different countries. Visiting fellows and scholars from Asia play an integral part in AHPP’s research, publishing, and outreach activities.

Since AHPP’s founding in 2007, the program has hosted 10 visitors from Asia, including Cambodia, China, and Korea, and, in the coming academic year, it will welcome three new visitors, from Japan, Mongolia, and the Philippines. In just five years AHPP has established strong postdoctoral and developing Asia fellowship programs, in addition to the visiting scholars it hosts. Lasting ties have been established, resulting in numerous publications as well as research and outreach projects in Asia.

Even now we still keep in touch and collaborate on certain research areas.
-Yan Wang, 2009–10 Visiting Scholar

Three former AHPP visitors recently spoke about their experience with the program and about the work they have been doing since their time at Stanford.

Young Kyung Do, AHPP’s inaugural postdoctoral fellow (2008–09), conducted research on the social and economic implications of population aging in Asia. Focusing on education and diabetes care, Do also examined the impact of socioeconomic disparities on the health and health care of elderly citizens. AHPP helped define his future research agenda, and also provided him with publishing opportunities, including collaborating on a chapter on diabetes in the edited volume Aging Asia (2010). Do is now an assistant professor with the Duke-National University of Singapore Graduate Medical School, where he studies health economics and policy issues related to population aging and noncommunicable diseases in Southeast and East Asia.

Byongho Tchoe served as a visiting scholar during the 2008–09 academic year, researching and writing about health care reform in South Korea. Tchoe enjoyed conducting research in Stanford’s peaceful campus environment, and taking part in seminars offered by the Shorenstein Asia-Pacific Research Center and other Stanford organizations. He contributed the chapter “Old-Age Pension Reform in South Korea” to Aging Asia, and published a working paper and article on the impact of population aging on medical costs in South Korea. Tchoe is now the president of the Korea Institute for Health and Social Affairs in Seoul.

Yan Wang (former), an AHPP visiting scholar from 2009 to 2010, is currently deputy director of the Division of Disease Control in the Health Department of China’s Shandong Province. At AHPP, Wang studied how private health care providers, in conjunction with government-run health services, can help improve the overall primary care available in China’s cities. She also collaborated with Stanford’s Asian Liver Center to develop an online program to provide better hepatitis B education to health professionals in Shandong. Wang appreciated attending AHPP seminars and learning about health reform around the world, and still remains in touch with some of the scholars she connected with during her time at Stanford.

AHPP looks forward to continuing to welcome and collaborate with visiting fellows and scholars in the coming years, and to expanding its postdoctoral and developing Asia fellowship programs.

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.

How well do textbooks educate school children about malaria prevention and treatment? AHPP's Siyan Yi took part in a study that examined textbooks from countries with high Malaria rates -- Laos, Cambodia, Nepal, Bangladesh, Sri Lanka, Zambia, Niger, Benin, and Ghana -- and recently published its findings in the open-access journal PLoS ONE.