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New evidence on running shoes

April 10, 2012 By 6 Comments

If you frequent a trail or neighborhood that is popular with runners, you’ve most likely noticed a new trend: people running barefoot or with very odd-looking shoes that place for each toe. And if you’re a runner yourself, you’ve certainly come across – maybe even experimented with – the trend of barefoot running.

Books like ChiRunning and Born to Run make the case for lower-profile, less-cushioned shoes or none at all. Here at EBL, we’ve written about the phenomenon before – specifically the work of Harvard biologist Daniel Lieberman, who studies the biomechanics of barefoot running and how early humans survived by evolving the ability to travel long distances to hunt.

Now a new study – detailed by a New York Times blog – has found that wearing light-weight shoes, instead of going completely barefoot, is metabolically more efficient.

The researchers’ argument goes something like this:  Running with traditional running shoes, which weight 300 to 400 grams, increase the amount of energy required to run because with every step, the running is lifting those weights.  Over the miles, that extra energy adds up.

For this study, researchers compared runners in lightweight shoes – weighing 150 grams – to barefoot runners who ran with leaded strips weighing 150 grams taped to the top of their feet. Carrying the same weight, the study found that barefoot running was actually less efficient compared to wearing light-weight shoes.

“What we found was that there seem to be adaptations that occur during the running stride that can make wearing shoes metabolically less costly,” Jason R. Franz, a doctoral candidate at the University of Colorado who led the study, told the New York Times. Shoes, he says, “provide some degree of cushioning.” If you eschew shoes, “something else has to provide the cushioning.”

Without any shoes, a runner’s leg muscles require additional energy to provide this cushioning.

In fact, the study even found that unweighted barefoot running was slightly less efficient than running with light-weight shoes, even though the shoes added weight.

The study didn’t address other benefits that barefoot runners tout – namely a reduction in injuries from running without shoes. But the study does make the case for investing in a different kind of running shoe – not the cushioned, bulky trainer that was once popular, but a more protective, lighter shoe that protects feet without adding weight.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , ,

BPA: The answer is in the details

April 2, 2012 By 1 Comment

The U.S. Food and Drug Administration decided not to ban the chemical bisphenol A, also known as BPA, in food packaging last week. The decision may seem like a surprising one since so many water bottles and serving utensils are sold as “BPA-free.” So let’s look at the evidence behind their decision.

National Public Radio offered a good overview of the evidence available on the health effect of BPA. The story noted that evidence from government agencies typically weighs heavier in FDA decisions.

One worry with other studies in contamination – BPA accidentally getting into the blood after samples are drawn. Some studies have found high levels of BPA in the blood. But these studies used samples collected in hospitals or doctors’ offices, not research settings and did not include a common test to detect contamination.

One study performed by government scientists involved feeding 20 adults a diet high in BPA from packaged foods for a day, and then measuring how much of it ended up in their blood.  At the end of the day, there wasn’t enough BPA in participants’ blood to measure.

That’s because the human body can he human body can actually inactivate dangerous chemicals like BPA in the intestine and liver, Justin Teeguarden, a toxicologist at the Pacific Northwest National Lab who conducted the study, told NPR.  Contamination was also an issue in this study, but the researchers tested for it and overcame it, he said.

Other government studies found that very little BPA is transferred to a nursing mother’s breast milk, and that  newborn monkeys are able to inactivate BPA just like human adults. (Researchers aren’t able to conduct studies on newborn babies.)

While the evidence does not show that BPA is completely safe, the FDA found that the low levels of BPA that humans are safe.

As for me, I’m still going to avoid BPA when I can. With the pressure on companies to remove from their products, there are plenty of BPA-free alternatives available, especially for kids. Any other BPA from canned food or juice containers, I’m not going to worry about for the moment.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , ,

The buzz on red meat

March 20, 2012 By 3 Comments

Last week, the headlines on meat consumption were inflammatory to say the least.

The Los Angeles Times: All red meat is bad for you, study finds Fox News: Red meat linked to premature death, research finds
The BBC: More Red Meat, More Mortality
The New York Times: Red Meat Increases Death, Cancer and Heart Risk

The researchers, from the Harvard School of Public Health, followed the diets and health outcomes of 37,000 men and 83,000 women over more than two decades. The found those who ate protein sources other than red meat were more likely to live longer. But what’s really at work here?

I found several systematic reviews on red meat consumption that give a broader look at this issue.

One published in the journal Circulation found 20 case-controlled studies and randomized controlled trials that assessed the effect of red meat consumption on health and concluded that eating processed meats, but not red meat, is associated with higher incidence of heart disease and diabetes.

Another review looked at the link between red meat consumption and colorectal cancer, and found eating red meat on a daily basis is associated with an increased risk of colorectal cancer and eating processed meats regularly is associated with an even higher risk of colorectal cancer.

And a third review found little evidence available on the links between red meat consumption and stroke risk.

As much as I love a good burger or juicy steak, the available evidence shows that eating red meat regularly is bad for your health. It is worth noting ,though, that in each study, the conclusions were drawn based on participants consuming red meat every day.

Personally, I’m going to stick with my motto of everything in moderation, and still enjoy a nice cut of beef once in a while.

Filed Under: Evidence-Based Living, In The Media Tagged With: , , , , ,

The body of evidence on chocolate and heart disease

March 15, 2012 By 2 Comments

If you regularly read any health or wellness publications, you’ve likely heard the assertion that chocolate is good for you – usually phrased something like this: “Thinking about skipping dessert?  Think again. A new study shows that chocolate is actually heart-healthy.”

But what does all of the evidence say about chocolate?  Is it really good for your health?  A systematic review published in the Journal of Nutrition has found that, yes, chocolate is really good for your health.

The review looked at the effect of flavonoid-rich cocoa on all cardiovascular risk factors such as blood pressure, cholesterol and insulin sensitivity.  It also evaluated the dose-response relationships between cocoa and cardiovascular risk factors.

The review included a total of twenty-four studies with 1,106 participants.  It found that chocolate had positive effects on a number of cardiovascular risk factors – blood pressure, insulin resistance, lipid profiles and cholesterol.

While that’s good news for dessert-lovers far and wide, there was a limitation of the available evidence – the studies only looked at benefits over the short-term – days or weeks. The review concluded with a call for long-term investigations into effects of cocoa on the heart.

In the meantime, you can still pass the chocolate to me.

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Do women hurt more than men?

January 31, 2012 By Leave a Comment

Pain is a medical issue so pervasive that it will impact the majority of Americans at some point in their lives. Here on EBL, we’ve written before about the issue of chronic pain, which effects nearly 116 million Americans.

Now new research out of Stanford University suggests that women suffer more from pain than men, even when both sexes have the same condition.

The study, published this week in the Journal of Pain, is not a systematic review, but it is the largest study of its kind to look at gender issues and pain. In it, researchers analyze the medical records of 11,000 patients whose pain scores were recorded as a routine part of their care.

Of the 22 medical problems analyzed in the study, women reported higher pain levels for 21 of them including back pain, joint pain and sinus infections. Overall, women’s pain levels were about 20 percent higher than men’s. And for several of the ailments, women’s average pain score one point or more higher than men’s – a clinically significant difference.

And it’s not the first study to raise the question of gender differences in pain. An international consensus report in 2007 suggested that hormones may play a role in the brain’s response to pain, and even went so far as to suggest that women may need different analgesia pharmaceuticals than men.

Another study out of England in 2003 suggested women are more sensitive to pain caused by pressure compared to men.

All very suggestive, but this literature on pain and gender differences raises more questions than it provides answers.  As a recent Institute of Medicine report confirms, much more research is needed on the effects of pain.

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New evidence on global warming

January 19, 2012 By 1 Comment

An international team of researchers have developed a new plan to slow climate change – one that involves reducing levels of two of the lesser-known contributors to global warming.

Their paper, published this week in the journal Science, recommends 14 actions to reduce emissions of methane gas – a greenhouse gas more powerful than carbon dioxide – and black carbon – the technical term for soot, which absorbs heat from the sun’s rays.

Among the measures they suggest are:

  • encouraging people to use switch cleaner diesel engines and cookstoves
  • building more efficient kilns and coke ovens
  • capturing methane at landfills and oil wells
  • reducing methane emissions from rice paddies by draining them more often.

Adopting the study’s recommendations would reduce projected temperatures by approximately 0.5°C by 2050, as well as avoiding millions of premature deaths due to air pollution and increasing crop yields thanks to reductions in ozone.

The proposal is a projection, to be sure.  But there is a large body of evidence available that shows there are many benefits to reducing these contaminants.

Systematic reviews show that reducing soot levels improves lung function and pregnancy outcomes. And it’s been clearly documented that methane gas warms the atmosphere, and that reducing its levels will boost agricultural yields.

So, in fact, the new study delivers another benefit, as noted in this New York Times column: it offers practical solutions with the immediate benefits of improving health and helping farmers produce more.

To us, it seems like a proposal worth putting into practice.

Filed Under: Evidence-Based Living, In The Media, policy Tagged With: , , , , ,

The best thing for kids: A supportive environment

January 13, 2012 By 2 Comments

The vast majority of parents – regardless of their income, education or upbringing – want the best for their children. I know that I never imagined the lengths I would go through for another human being until I held a tiny baby in my arms.

This week, the American Academy of Pediatrics issued a policy statement explaining exactly what parents can do to ensure their children’s health and development: avoid toxic stress.

(Before we go on, a quick word about policy statements:  Similar to systematic reviews, they involved a panel of experts – in this case pediatricians – who review the body of evidence on a given topic and make a recommendation based on the available research. So they’re a big deal.)

The statement explains that personal experiences and environmental factors that activate the physiological stress response for prolonged periods of time disrupt children’s brain circuitry and can have an impact on physiology, behavior and health even decades later. Essentially, too many or too long stressful experiences is bad for kids. The statement is referring to major, lasting problems: verbal abuse in the home, a chronic lack of affection for children, physical threats to family members, an addiction problem.

The statement builds on the research of Cornell faculty member Gary Evans, an environmental psychologist who studies the impact of the physical environment and poverty on children. Evans research has shown that growing up in an environment of poverty can lead to health problems.

In another study, Evans looked at the impact of noisy environments on children’s development.

“People tend to think of noise in terms of how it impacts hearing,” he explained. “But if you are subjected to noise, you’re likely to have elevated blood pressure and elevated stress hormones, and those have real implications for your health. Children who grow up in noisy environments are more likely to have deficits in reading because if you tune out noise in general, you also tune out speech. And language is a fundamental building block for learning to read.”

A third study, published in the journal Pediatrics this month, found children who undergo chronic stress have larger gains in their Body Mass Index, suggesting chronic stress leads to weight gain.

The statement makes the arguments that pediatricians – who hold some responsibility for ensuring children’s health – should do more to ensure kids are growing up in health environments. This could mean developmental screenings, connecting families with social services, and supporting community programs that provide positive environments for children.

You can read more about the policy statement and its implications in this New York Times opinion column. And then take the time to make sure the children in your life – whether they’re your own kids, other relatives or neighbors – feel a little more secure and loved. It can go a long way to making a difference in the rest of their lives.

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Missing data: The Achilles heel of systematic reviews

January 6, 2012 By Leave a Comment

If you’re a regular reader of EBL, you know we’re huge fans of systematic reviews – studies in which researchers use sophisticated methods to bring together and evaluate the dozens, hundreds, or even thousands of articles on a topic.

We value these analyses because they collect all of the information available and then look at why and how each study differs. By looking at so many studies, researchers can make general conclusions, even though participants and study settings might be different.

So we took a great interest this week in a series of studies in the British Medical Journal making the case that many medical studies aren’t published, and therefore missing from systematic reviews and the decision-making processes of doctors and patients.

One of the studies found that fewer than half of the clinical trials funded by the National Institutes of Health from 2005 to 2008 were published in peer-reviewed journals within 30 months of study completion, and only 68 percent were published at all.

Another examined trials registered at the federal web site ClinicalTrials.gov during 2009. Of the 738 studies registered and subject to mandatory reporting guidelines (per the rules of the U.S. Food and Drug Administration), only 22 percent reported results within one year.  (It’s interesting to note that trials of medicines in the later stages of development and those funded by the drug industry were more likely to have results reported.)

A third study re-analyzed 41 systematic reviews of nine different medicines, this time including unpublished clinical trial data from the FDA in each analysis.  For 19 of the systematic reviews, the addition of unpublished data led to the conclusion that the drug was not as effective as originally shown. For 19 other reviews, the additional data led to the conclusion that the drug was more effective than originally shown.

Dr. Harlan Krumholz, a cardiologist at Yale and a internationally-respected expert in outcomes research, summarized the issue in his Forbes magazine blog, including some of the reasons that data goes unreported. (Among them, researchers may not be happy with the results or may shift focus to a new study. And medical journals may not be receptive to negative results.)

Whatever the reasons, the take-home message seems to be that researchers and publishers need to do a better job getting all of the information out in the public domain so that doctors and patients can truly make informed decisions.

Filed Under: Evidence-Based Living, In The Media, The Learning Center Tagged With: , , , ,

Can you boost your IQ? The evidence says yes

December 7, 2011 By 1 Comment

It’s an age-old question studied by researchers for more than a century:  Is there anyone to make your-self smarter?

In the early days of this inquiry, researchers were certain the answer was no.  But studies over the past two decade have proven otherwise.  Yes, you can raise your intelligence quotient, or IQ.   In fact, the very question was covered in a recent Wall Street Journal article.

While I didn’t manage to track down a systematic review of the topic, I did find a body of literature pointing to methods for improving your IQ.  One study that followed 250 adults over the course of six years found that people in jobs involving complex relationships, elaborate systems or difficult problems tend to perform better over time on cognitive tests.

Likewise, the work of Cornell Professor Steve Ceci has found that schooling raises IQ by several points a year, mainly because students are exposed to information and problem-solving often included in cognitive tests.

In another recent study, British students were given IQ tests and brain scans at ages 12 to 16 and again four years later. The students with significant improvements in IQ – 15 points or more – showed changes in gray matter in areas corresponding with their improvements.

Alas, the issue is complicated.  Another recent study tested adults using at Wii video game, reading and reference ability. While the participants showed improvements in what they practiced, their new-found skills didn’t transfer well to other areas, suggesting that learning for adults may be more narrow than for young adults and children.

Clearly, more research is needed. But it seems that we can say definitely that if you practice something – whether physical or mental – you will see improvements in that specific area.

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Everything you need to know about vitamin supplements

October 26, 2011 By 4 Comments

Now and again, a study is published that leads to a sea change in public opinion. If you’re a regular EBL reader, you already know how we feel about this. (While a single study provides some evidence about an issue, we should really consider all of the available evidence on a given topic before drawing any conclusions.)

Earlier this month, it wasn’t one study, but two.  Separate reports on the use of multivitamins and supplements among older women and the use of Vitamin E and selenium to prevent prostate cancer have led to a flurry of media reports about whether or not we, the general public, should take supplemental vitamins.

What does that mean for you?  We’ve done our best to dissect all of the evidence we can find.  Let’s start with the most recent studies.

First, researchers followed more than 38,000 older women for 25 years to track, among other things, their use of multivitamins and supplements. The study found that the risk of death among these women increased with long term use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc, and copper. They concluded there is “little justification for the general and widespread use of dietary supplements.”

In the second study, researchers followed more than 35,000 men over 10 years to determine whether taking vitamin E or selenium would decrease the risk of prostate cancer. In this study, the risk of cancer increased for men taking vitamin E, selenium, or both. This study also concluded there is little evidence for taking a supplement.

While these are both large, longitudinal studies, we thought it’d be prudent to check the other evidence available on supplements and talk to some Cornell nutrition professors about their interpretation of the data.

We started off at the Cochrane Collaboration, which has dozens of review on specific supplements for specific conditions. The most general report reviewed studies of supplements to prevent mortality. It reviewed 67 randomized trials with more than 200,000 participants, and found no evidence that supplements prolong life. It also concluded that Vitamin A, beta-carotene, and vitamin E may be harmful.

J. Thomas Brenna, Cornell professor of nutritional sciences, draws the same conclusions. “Human trials of so-called antioxidants have generally been neutral or shown harm, and these recent reports are consistent with their findings,” he said.

Brenna’s take on vitamins and supplements boils down to what he calls one of the oldest and most reliable mantras in biological science, “The dose make the poison.”  In other words, you can get too much of a good thing, and excess vitamin supplementation is no exception.

Patsy Brannon, also a professor of nutritional sciences, emphasized the need to consider your total intake of vitamins and minerals. 

“We know that those who take vitamin and mineral supplements tend to be consuming a healthier diet,” she said. “Further, many foods are fortified with minerals and vitamins such as ready-to-eat cereals and fruit justices.”

So who might benefit from a supplement and how to decide on what supplement to take and how much? 

“For those who routinely consume less than 1500 calories per day, it may be hard to consume all the vitamins and minerals in the amounts needed.  Then, a multivitamin-mineral supplement that provides only 100 percent of the recommended daily values for each of the nutrients in the supplement would be helpful,” she said.

Brannon pointed out a recent study published in the Journal of Nutrition that many adults are not meeting their nutritional needs.  Other evidence found only about 25 percent of American adults are following the recommended dietary guidelines.

The bottom line: Yes, supplements are important for specific deficiencies or when diets do not include a healthy variety of foods.  But the public as a whole may be overconsuming them to ensure health. When that happens, they may do some harm.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , , ,

New evidence on yoga

October 20, 2011 By 2 Comments

Here on EBL, we’ve written plenty about alternative treatments like T’ai Chi and meditation. They’re always popular topics, maybe because many of us are looking for ways to improve our health.

So I was excited to see a New York Times blog post about the evidence surrounding yoga and pain relief. For one, it’s great news that major media outlets like the New York Times are touting the importance of systematic reviews.  And it’s also good to hear that an alternative treatment practiced by so many people – myself included – actually works.

The actual analysis, conducted by researchers in the United Kingdom and published in the Journal of Alternative and Complementary Medicine, reviewed ten randomized clinical trials that measured whether yoga helped reduce pain among patients with a variety of ailments. Nine of the trials found yoga led to significantly greater pain reduction than other therapies such as standard care, therapeutic exercises, touch and manipulation, or no intervention at all.

While the analysis gave preliminary indications that yoga works for pain relief, it concluded that more research is needed. The yoga practices in each of the studies varied widely, as did the type and intensity of pain experienced by patients.

Dr. M. Cary Reid is a geriatrician at Weill Cornell Medical Center and director the Translational Research Institute for Pain in Later Life, an evidence-based center in New York City to help older adults prevent and manage pain. He recently completed his own systematic review of alternative therapies including yoga for the treatment of osteoarthritis, which is submitted for publication.

Dr. Reid shared his thoughts on yoga for pain relief: “The good news is there appear to be few downsides to doing yoga, so my thinking is that we should be offering it routinely to patients, particularly those who are reluctant to try pain medications.” He echoed the need for larger, more definitive studies.

Until then, I’ll still be frequently my local yoga studio.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , ,

Is junk food cheaper?

October 11, 2011 By 1 Comment

It’s a major misconception in our modern society: processed foods like chips, frozen dinners and Happy Meals are not cheaper, but actually more expensive than whole foods like whole grains, fruits and vegetables. While this topic graces our TV screens in shows like Jamie Oliver’s Food Revoluion and our shelves in books like Michael Pollan’s In Defense of Food, the misconception remains among many Americans.

A few weeks ago, Mark Bittman wrote a column in the New York Times making the case that cost is not what keeps American families from eating healthy meals.  Bittman argues that advertising and marketing of snacks and fast food, the addictive nature of unhealthy foods and a lack of cooking skills are to blame for America’s nutrition problems.

It’s a problem that is documented by plenty of evidence, says Christine Olson, a professor of community nutrition at Cornell.

“His article lends some visibility to a fact that is well-known by nutritionists and family economists and amply-substantiated by research,” she said. “A home-prepared family meal is generally more nutritious and cheaper than a family meal purchased at a restaurant, even a fast food restaurant.  But the frenetic pace of family life and the relentless advertising by the fast food industry contribute to the widely-held opposite perception. “

Cornell Cooperative Extension has been educating families about this very issue for decades. Its Food and Nutrition Education in Communities program has been helping families gain the knowledge, skills, attitudes they need to eat healthily since the 1970s. Another program called Cooking Up Fun teaches young people about cooking with healthy ingredients.

It’s one of the many ways that Cornell Cooperative Extension is using evidence to help improve the lives of families in New York.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , , ,
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