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Autoimmune Disease, Evolution, Immunology, Microbiology, Nutrition, Public Health, Stanford News

Civilization and its dietary (dis)contents: Do modern diets starve our gut-microbial community?

Civilization and its dietary (dis)contents: Do modern diets starve our gut-microbial community?

hunter-gatherer cafe

Our genes have evolved a bit over the last 50,000 years of human evolution, but our diets have evolved a lot. That’s because civilization has transitioned from a hunter-gatherer lifestyle to an agrarian and, more recently and incompletely, to an industrialized one. These days, many of us are living in an information-intensive, symbol-analyzing, button-pushing, fast-food-munching society. This transformation has been accompanied by consequential twists and turns regarding what we eat, and how and when we eat it.

Toss in antibiotics, sedentary lifestyles, and massive improvements in public sanitation and personal hygiene, and now you’re talking about serious shake-ups in how many and which microbes we get exposed to – and how many of which ones wind up inhabiting our gut.

In a review published in Cell Metabolism, Stanford married-microbiologist couple Justin Sonnenburg, PhD, and Erica Sonnenburg, PhD, warn that modern civilization and its dietary contents may be putting our microbial gut communities, and our health, at risk.

[S]tudies in recent years have implicated [dysfunctional gut-bug communities] in a growing list of Western diseases, such as metabolic syndrome, inflammatory bowel disease, and cancer. … The major dietary shifts occurring between the hunter-gatherer lifestyle, early Neolithic farming, and more recently during the Industrial Revolution are reflected in changes in microbial membership within dental tartar of European skeletons throughout these periods. … Traditional societies typically have much lower rates of Western diseases.

Every healthy human harbors an interactive internal ecosystem consisting of something like 1,000 species of intestinal microbes.  As individuals, these resident Lilliputians may be tiny, but what they lack in size they make up in number. Down in the lower part of your large intestine dwell tens of trillions of  single-celled creatures – a good 10 of them for every one of yours. If you could put them all on a scale, they would cumulatively weigh about four pounds. (Your brain weighs three.)

Together they do great things. In a Stanford Medicine article I wrote a few years back, “Caution: Do Not Debug,” I wrote:

The communities of micro-organisms lining or swimming around in our body cavities … work hard for their living. They synthesize biomolecules that manipulate us in ways that are helpful to both them and us. They produce vitamins, repel pathogens, trigger key aspects of our physiological development, educate our immune system, help us digest our food and for the most part get along so well with us and with one other that we forget they’re there.

But when our internal microbes don’t get enough of the right complex carbohydrates (ones we can’t digest and so pass along to our neighbors downstairs), they may be forced to subsist on the fleece of long carbohydrate chains (some call it “mucus”)  lining and guarding the intestinal wall. Weakening that barrier could encourage inflammation.

The Sonnenburgs note that certain types of fatty substances are overwhelmingly the product of carbohydrate fermentation by gut microbes. These substances have been shown to exert numerous anti-inflammatory effects in the body, possibly protecting against asthma and eczema: two allergic conditions whose incidence has soared in developed countries and seems oddly correlated with the degree to which the environment a child grows up in is spotlessly hygienic.

Previously: Joyride: Brief post-antibiotic sugar spike gives pathogens a lift, The future of probiotics and Researchers manipulate microbes in the gut
Photo by geraldbrazell

Public Health, Public Safety, Research, Technology

Mining Twitter to identify cases of foodborne illness

During this year’s Big Data in Biomedicine conference at Stanford, Taha Kass-Hout, MD, chief health informatics officer for the U.S. Food and Drug Administration, talked about the potential of social media to monitor food safety saying, “You are what you eat, and in this world, you are what you tweet.” Taking this concept into a real-world setting, officials at the Chicago Department of Public Health developed an algorithm to mine Chicago-based tweets for sentiments of food illnesses and, as a result, were able to investigate incidents of food poisoning that would have otherwise gone unnoticed. According to a recent article in Popular Science:

… in a recent project, the city of Chicago sought food poisoning cases by setting an algorithm to mine Chicago-area tweets for complaints. The Chicago Department of Public Health’s Twitter bot, plus a new online complaint form, helped the department identify 133 restaurants for inspections over a 10-month period. Twenty-one of those restaurants failed inspection and 33 passed with “critical or serious” violations. Not a bad haul.

Chicago is now working with the health departments of Boston and New York to see if its system could work in those cities, according to a report city researchers published with the U.S. Centers for Disease Control and Prevention. Plus, Twitter isn’t the only social media platform cities are looking to mine for public health violations. In May, New York City’s department of health reported on using an algorithm to spot Yelp reviews that point to food poisoning cases. New York’s Yelp project led the city to discover three restaurants that had multiple violations. All the Yelp cases the city inspected had otherwise gone unreported, New York officials wrote in their own CDC report.

The Chicago bot was pretty simple, as Twitter-reading computer programs go. It searched for tweets geo-located to Chicago and its surrounding suburbs that mentioned “food poisoning.” Human staff then read the tweets to determine if they were relevant. (Sounds fun.) Staff marked tweets as relevant or not relevant, to give the algorithm data to better learn what tweets to pull in the future. Then staff members responded to relevant tweets themselves.

Previously: Videos of Big Data in Biomedicine keynotes and panel discussions now available online, Discussing access and transparency of big data in government and Improving methods for tracking flu trends using Twitter

From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Cancer, Parenting, Pediatrics, Public Health, Research

Study shows number of American teens using sunscreen is declining

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Despite an increase in cases of melanoma, the most dangerous type of skin cancer, growing percentage of high school students get a failing grade when it comes to using sunscreen. HealthDay reports:

The number of U.S. teens using sunscreen dropped nearly 12 percent in the last decade, a new report shows.

During that same time period, the number of teens using indoor tanning beds barely decreased. Both indoor tanning and failure to use sunscreen increase the risk of skin cancers, including deadly melanomas, the researchers noted.

“Unfortunately, we found a decrease in the overall percentage of teens who reported wearing sunscreen, from 67.7 percent in 2001 to 56.1 percent in 2011,” said lead researcher Corey Basch, an associate professor in the department of public health at William Paterson University in Wayne, N.J.

“Using sun-protective behaviors like applying sunscreen and avoiding intentional exposure to tanning devices will be key [to lowering cancer risk],” she added.

Use of indoor tanning devices by white girls decreased only slightly, from 37 percent in 2009 to 29 percent in 2011, she said.

Study authors say more research is need to understand why teens aren’t following national guidelines regarding sun protection.

Previously: Melanoma rates exceed rates of lung cancer in some areas, Beat the heat – and protect your skin from the sun, Working to protect athletes from sun dangers and Stanford study: Young men more likely to succumb to melanoma
Photo by Alex Liivet

From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Global Health, Infectious Disease, Public Health, Public Safety, Stanford News

Biosecurity experts discuss Ebola and related public health concerns and policy implications

Biosecurity experts discuss Ebola and related public health concerns and policy implications

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More than 1,800 people in the West African nations of Liberia, Sierra Leone and Guinea have contracted the Ebola virus since March and the death toll has surpassed 1,000, according to the latest figures from the World Health Organization. As the number of cases and death continue to climb many are concerned about what can be done to curtail the outbreak and the likelihood of it spreading to the United States.

In a Q&A recently published by the Center for International Security and Cooperation and The Freeman Spogli Institute for International Studies, Stanford biosecurity experts David Relman, MD, and Megan Palmer jointly answer these questions and others related to the public health concerns and policy implications of the outbreak. On the topic of broader lessons about the dynamics and ecology of emerging infectious diseases that can help prevent or respond to outbreaks now and in the future, they respond:

These latest outbreaks remind us that potential pathogens are circulating, replicating and evolving in the environment all the time, and human action can have an immense impact on the emergence and spread of infectious disease.

We are starting to see common factors that may be contributing to the frequency and severity of outbreaks. Increasing human intrusion into zoonotic disease reservoir habitats and natural ecosystems, increasing imbalance and instability at the human-animal-vector interface, and more human population displacement all are likely to increase the chance of outbreaks like Ebola.

The epicenter of this latest outbreak was Guéckédou, a village near the Guinean Forest Region. The forest there has been routinely exploited, logged, and neglected over the years, leading to an abysmal ecological status quo. This, in combination with the influx of refugees from conflicts in Guinea, Liberia, Sierra Leone, and Cote d’Ivoire, has compounded the ecological issues in the area, potentially facilitating the spread of Ebola. There seems to be a strong relationship between ecological health and the spread of disease, and this latest outbreak is no exception.

While forensic analyses are ongoing, unregulated food and animal trade in general is also a key factor in the spread of infectious diseases across large geographic regions. Some studies suggest that trade of primates, including great apes, and other animals such as bats, may be responsible for transit of this Ebola strain from Central to Western Africa.

Overall, Relman and Palmer remind the public, “It’s important that we not lose sight of more chronic, but less headline-grabbing diseases that will be pervasive, insidious long-standing challenges for Africa and elsewhere.”

Previously: Stanford global health chief launches campaign to help contain Ebola outbreak in Liberia and Health workers use crowdsourced maps to respond to Ebola outbreak in Guinea
Photo by European Commission DG ECHO

From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Ethics, Events, Health Policy, Medicine and Society, Public Health, Transplants

Stanford Health Policy forum on organ-donation crisis now available online

Stanford Health Policy forum on organ-donation crisis now available online

The latest Stanford Health Policy Forum, which focused on ways to end our country’s organ-donor shortage, is now available online. More than 100,000 Americans currently need organ transplants, and the panelists discussed a variety of solutions for solving the problem. Among the ideas brought to the table was a compensation system for donors – an option that was also the focus of an article in today’s San Francisco Chronicle.

Previously: At Stanford Health Policy Forum, panelists dig into the issue of organ donationHow can we end the donor organ shortage?, Stanford visiting professor and founder of kidney-exchange program wins Nobel economics prize and One gift saves three young lives 

In the News, Public Health, Research, Science, Stanford News, Technology

NPR highlights Google’s Baseline Study and what it might teach us about human health

NPR highlights Google's Baseline Study and what it might teach us about human health

Late last month, my colleague reported on Stanford partnering with Google [x] and Duke on a research study to better understand the human body. On the most recent edition of NPR’s Science Friday, project collaborator Sanjiv Sam Gambhir, MD, PhD, professor of radiology at Stanford, discussed the project and joined Jason Moore, MD, professor of genetics at Dartmouth College, in a segment called “Will big data answer big questions on health?”

According to Gambhir, what makes the new project unique is the focus on understanding the baseline of healthy human beings. Will it ultimately yield meaningful data about what makes us healthy? Listen here for the researchers’ thoughts.

Jen Baxter is a freelance writer and photographer. After spending eight years working for Kaiser Permanente Health plan she took a self-imposed sabbatical to travel around South East Asia and become a blogger. She enjoys writing about nutrition, meditation, and mental health, and finding personal stories that inspire people to take responsibility for their own well-being. Her website and blog can be found at www.jenbaxter.com.

Previously: Stanford partnering with Google and Duke to better understand the human body

Addiction, In the News, Public Health, Public Safety

Can the “24/7 sobriety” model reduce drunken disorderly conduct and violence in London?

beer_london_pubIn an article published yesterday in the Telegraph, Stanford addiction expert Keith Humphreys, PhD, discusses how public officials in London are turning to the United States’ “24/7 sobriety” model in an effort to reduce repeat offenders convicted of alcohol-related crimes. The program, which combines mandatory sobriety and daily breathalyser tests, was created under Humphreys’ guidance. He writes:

Research by the RAND Corporation – a US-based non-profit global policy think tank – found that 24/7 sobriety dropped repeat drink driving arrests by 12 per cent. The same study also yielded a pleasant surprise: domestic violence arrests dropped by 9 per cent, despite not being a focus of the programme. Removing alcohol from the lives of criminals can apparently have radiating benefits beyond those directly related to their most recent offence.

In light of its positive results, judges across the U.S. have been adopting the 24/7 sobriety approach. This week, under the leadership of Mayor Johnson and his team, a pilot of the programme will be launched in South London. Leaping the pond will come with some challenges, particularly around delivering sanctions swiftly within the constraints of British law, but local tailoring of innovations is always an essential part of making them spread.

In any event, with over one million alcohol-related assaults occurring nationally each year and many London boroughs being regularly marred by violence and disorder on weekend evenings, the time for new approaches to binge drinking criminal offenders has clearly arrived. The judges and probation officers who are undertaking this pilot should be applauded for refusing to accept the status quo.

Previously: Text messages after ER visit could reduce young adults’ binge drinking by more than 50 percent, Study shows legal drinking age of 21 saves lives and reduces health risks for young adults, Alcoholism: Not just a man’s problem and Stopping criminal men from drinking reduces domestic violence
Photo by Paul Downey

Cancer, Dermatology, Public Health, Research, Stanford News

Melanoma rates exceed rates of lung cancer in some areas

Melanoma rates exceed rates of lung cancer in some areas

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Californians, step away from the beach and grab a hat and sunscreen. Our team of researchers from the Cancer Prevention Institute of California/Stanford Cancer Institute released a new report (.pdf) this week documenting the rapidly growing burden of melanoma in Marin County, California. This small, homogenous (and wealthy) county just over the Golden Gate Bridge from San Francisco has been the focus of cancer studies before, as high rates of breast cancer were first reported there in the late 1990’s (rates declined there as in the rest of the country in 2003 when women stopped taking hormone therapy).

Our most recent cancer registry data show that rates of malignant melanomas in Marin County are 43 percent higher than the rest of the San Francisco Bay Area and 60 percent higher than other parts of California among non-Hispanic whites, who because of their fairer skin tones are diagnosed with melanoma at 20-30 times the rate of other ethnic groups. Also of concern is that the death rate due to melanoma is 18 percent higher in Marin whites than whites in other regions, a significant difference not seen before. Most of the elevated rates are limited to persons over age 65, especially men.

The Bay Area news media reported our findings as front-page news. Most coverage centered on the question of why the rates are so much higher in Marin County. Our best guess is that the higher average socioeconomic status of its residents corresponds to a higher proportion of people with the known risk factors for melanoma: fair complexion (pale skin, blonde or red hair, blue or green eyes) and a history of “intense intermittent” sun exposure over their lifetimes (exposure in big doses like you might get on a beach vacation in the winter).

However, it is also likely that better access to health care and skin screening has resulted in earlier diagnosis, a notion confirmed by the higher proportion of melanomas in Marin County caught when thin and more curable. Local dermatologists reacted to the statistics with some surprise, but didn’t change their standing advice regarding skin cancer prevention: talk to your doctor about skin screening and stay sun safe by wearing hats, long-sleeves and broad-spectrum sunscreen during outdoor activities.

One statistic mostly overlooked by the media was our finding that melanoma is now the second most common cancer diagnosed in men living in Marin County, as rates have surpassed those for lung cancer. This pattern is very different than that observed for whites in the US and world, for whom prostate or lung are first, and melanoma is ranked much lower. With one of the most successful public tobacco control efforts in the world, most populations in California have seen rapid declines in the incidence of smoking-related cancers of the lung and respiratory system.

Unfortunately, it seems for older white persons in Marin County (as well as parts of Utah and Hawaii, where smoking rates have also declined), melanoma and skin cancers represent a major—and relentlessly growing—cancer threat. Perhaps putting down the cigarettes was accompanied by more time at the pool or beach without adequate sun protection. Although California was the first state to ban tanning bed use by minors, we should look to Australia and other countries also battling rising skin cancer rates for innovative new policies and strategies for encouraging safe sun exposure in our at-risk communities.

Christina A. Clarke, PhD, is a Research Scientist and Scientific Communications Advisor for the Cancer Prevention Institute of California, and a member of the Stanford Cancer Institute.

Previously: Beat the heat – and protect your skin from the sun, Working to protect athletes from sun dangers, As summer heats up take steps to protect your skin, Stanford study: Young men more likely to succumb to melanoma and How ultraviolet radiation changes the protective functions of human skin
Photo by stefan klocek

Health Disparities, Men's Health, Public Health, Research, Stanford News, Women's Health

Why it’s critical to study the impact of gender differences on diseases and treatments

man_womanWhen it comes to diagnosing disease and choosing a course of treatment, gender is a significant factor. In a Stanford BeWell Q&A, Marcia Stefanick, PhD, a professor of medicine at the Stanford Prevention Research Center and co-director of the Stanford Women & Sex Differences in Medicine Center, discusses why gender medicine research benefits both sexes and why physicians need to do a better job of taking sex difference into consideration when make medical decisions.

Below Stefanick explains why a lack of understanding about the different clinical manifestations of prevalent diseases in women and men can lead to health disparities:

…Because we may have primarily studied a particular disease in only one of the sexes, usually males (and most basic research is done in male rodents), the resulting treatments are most often based on that one sex’s physiology. Such treatments in the other sex might not be appropriate. One example is sleep medication. Ambien is the prescription medicine recently featured on the TV show, 60 Minutes. Reporters found out that women were getting twice the dose they should because they had been given the men’s doses; consequently, the women were falling asleep at the wheel and having accidents. Physicians had not taken into account that women are smaller and their livers’ metabolize drugs differently than do men’s. Some women have responded by reducing their own medication dosages, and yet that practice of self-adjusting is not the safest way to proceed, either.

Previously: A call to advance research on women’s health issues, Exploring sex differences in the brain and Women underrepresented in heart studies
Photo by Mary Anne Enriquez

Aging, Chronic Disease, Public Health, Research

How multiple chronic conditions are affecting older Americans’ life expectancy

old_coupleOne in four adults in the United States has two or more chronic conditions, according to the latest data from the Centers for Disease Control and Prevention. And, findings published in the August issue of Medical Care show that the burden of multiple chronic diseases could explain why life expectancy increases among elderly Americans are slowing.

In the study (subscription required), researchers at Johns Hopkins Bloomberg School of Public Health analyzed a nationally representative sample of 1.4 million Medicare beneficiaries. According to a release:

The analysis found that, on average, a 75-year-old American woman with no chronic conditions will live 17.3 additional years (that’s to more than 92 years old). But a 75-year-old woman with five chronic conditions will only live, on average, to the age of 87, and a 75-year-old woman with 10 or more chronic conditions will only live to the age of 80. Women continue to live longer than men, while white people live longer than black people.

It’s not just how many diseases you have, but also what disease that matters. At 67, an individual with heart disease is estimated to live an additional 21.2 years on average, while someone diagnosed with Alzheimer’s disease is only expected to live 12 additional years.

On average, life expectancy is reduced by 1.8 years with each additional chronic condition, the researchers found. But while the first disease shaves off just a fraction of a year off life expectancy for older people, the impact grows as the diseases add up.

Previously: Americans are living longer, but are we healthier in our golden years?, Longevity gene tied to nerve stem cell regeneration, say Stanford researchers, Study shows regular physical activity, even modest amounts, can add years to your life and TED Talk with Laura Carstensen shows older adults have an edge on happiness
Photo by Marcel Oosterwijk

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