CNO Report 197
Release Date 03 JAN 2015
Draft Report Compiled by
In This Issue:
- Televised medical talk shows: Health education or entertainment?
- Fast-food consumption linked to lower test score gains in 8th graders
- Weight training appears key to controlling belly fat
- Scientists uncover new, fundamental mechanism for how resveratrol provides health benefits
- Sugar molecule links red meat consumption and elevated cancer risk in mice
- Estrogen worsens allergic reactions in mice
- Daily multivitamin improves pregnancy outcomes in South Asia, JAMA study suggests
Televised medical talk shows: Health education or entertainment?
UAlberta researchers rate the recommendations of ‘Dr. Oz’ and ‘The Doctors’
University of Alberta Faculty of Medicine & Dentistry
(Edmonton) For millions of people around the world, televised medical talk shows have become a daily viewing ritual. Programs such as The Dr. Oz Show and The Doctors have attracted massive followings as charismatic hosts discuss new medical research and therapies while offering viewers their own recommendations for better health. For show producers it’s a winning ratings formula, but for viewers eager for a healthier life, the results aren’t so clear cut.
“The research supporting any of these recommendations is frequently absent, contradictory or of poor quality,” says Christina Korownyk, an associate professor in the Department of Family Medicine in the University of Alberta’s Faculty of Medicine & Dentistry.
“The public may see these shows as educational,” adds Mike Allan, a colleague and fellow professor in the Department of Family Medicine. “But in many ways we wonder if that’s really what they’re there for and perhaps they’re just there for entertainment.”
Korownyk and Allan are two of the authors of a new study published in the Christmas edition of the British Medical Journal, which examines the recommendations of televised medical talk shows. The researchers say they settled on the study after hearing concerns from several physicians whose patients took to heart the advice given on the shows.
“Some patients come in and say ‘I heard on Dr. Oz yesterday that we should all be doing this.’ And then we’re left scrambling in our office to try to find answers,” says Korownyk. “It got us reflecting, what’s being said there? What kinds of things are being recommended and what kind of information is being provided?”
To find an answer, the team chose two internationally syndicated medical talk shows to analyze: The Dr. Oz Show and The Doctors. Each show was recorded every day from January 2013 to April 2013. From there, the researchers randomly selected 40 episodes of each show and had two team members watch every episode independently, recording topics, recommendations made and who was making the recommendations. After that, another two researchers were brought in to re-watch the episodes, focusing on the information provided in the recommendations and answering the questions: was there a benefit mentioned? Was it specific? Did the show quantify the magnitude of the benefit? Did they mention costs? Did they mention conflict of interest?
The team then randomly selected 80 of the strongest recommendations from each show for further study, giving the medical researchers an hour per question to try and find out if there was any evidence to support what was being said. Korownyk says the results were revealing.
“One out of three recommendations from The Dr. Oz Show has believable evidence and about half of the recommendations on The Doctors has believable evidence.”
“Frequently you’re not getting enough information and without doing the research you won’t know if it’s supported by evidence or not,” adds Allan.
Among the other findings:
Most common topic discussed after general medical advice:
- The Dr. Oz Show – Dietary advice (43.2 percent)
- The Doctors – Dietary advice (16.8 percent)
Most common recommendations given:
- The Dr. Oz Show – Dietary advice (39.2 percent)
- The Doctors – Consult a health-care professional (17.8 percent)
Were specific benefits mentioned along with the recommendation?
- The Dr. Oz Show – (42.6 percent)
- The Doctors – (41.3 percent)
Was the magnitude of the benefit mentioned with the recommendation?
- The Dr. Oz Show – (16.5 percent)
- The Doctors – (11 percent)
Were possible harms mentioned?
- The Dr. Oz Show – (9.8 percent)
- The Doctors – (7.6 percent)
Were costs mentioned?
- The Dr. Oz Show – (12.5 percent)
- The Doctors – (3.1 percent)
Korownyk and Allan also note that out of 924 total recommendations examined, in only four instances were there accompanying mentions of potential conflict of interest by the presenter. Allan believes the sum of evidence shows viewers aren’t being given enough information to make the best decisions.
“It is limited and would not allow many patients to make a clear informed choice about what they’re hearing. They’re really taking these recommendations based on their trust of the host rather than making an informed choice based on the information provided.”
The researchers say it appears that general advice for the public is often not the best path for viewers to make their health decisions. And while televised medical talk shows may be great entertainment, listening to health-care providers who can give specific and balanced advice will leave people healthier and happier in the long run.
“Our bottom line conclusion is to be skeptical of what you hear on these shows,” says Allan.
Public Release: 22-Dec-2014
Fast-food consumption linked to lower test score gains in 8th graders
The more children ate in 5th grade, the slower their academic growth by 8th grade
Ohio State University
COLUMBUS, Ohio — The amount of fast food children eat may be linked to how well they do in school, a new nationwide study suggests.
Researchers found that the more frequently children reported eating fast food in fifth grade, the lower their growth in reading, math, and science test scores by the time they reached eighth grade.
Students who ate the most fast food had test score gains that were up to about 20 percent lower than those who didn’t eat any fast food, said Kelly Purtell, lead author of the study and assistant professor of human sciences at The Ohio State University.
“There’s a lot of evidence that fast-food consumption is linked to childhood obesity, but the problems don’t end there,” Purtell said. “Relying too much on fast food could hurt how well children do in the classroom.”
The results remained even after the researchers took into account a wide variety of other factors that may have explained why those with high fast-food consumption might have lower test scores, including how much they exercised, how much television they watched, what other food they ate, their family’s socioeconomic status and characteristics of their neighborhood and school.
“We went as far as we could to control for and take into account all the known factors that could be involved in how well children did on these tests,” Purtell said.
Purtell conducted the study with Elizabeth Gershoff, associate professor of human ecology at the University of Texas at Austin. The results are published online in the journal Clinical Pediatrics.
Data from the study came from the Early Childhood Longitudinal Study-Kindergarten Cohort, a nationally representative study of students who were in kindergarten in the 1998-1999 school year. It was collected by the National Center for Educational Statistics.
This study included about 11,740 students. They were tested in reading/literacy, mathematics and science in both fifth and eighth grades. They also completed a food consumption questionnaire in fifth grade.
“Fast-food consumption was quite high in these students,” Purtell said.
Less than a third (29 percent) of the children did not have any fast food during the week before they completed the questionnaire. But 10 percent reported having fast food every day while another 10 percent ate it four to six times a week. Slightly more than half of the children ate fast food one to three times in the previous week.
Children who ate fast food four to six times per week or every day showed significantly lower gains in all three achievement areas compared to children who did not eat any fast food the week before the survey.
However, children who ate fast food just one to three times a week had lower academic growth compared to non-eaters in only one subject, math.
“We’re not saying that parents should never feed their children fast food, but these results suggest fast-food consumption should be limited as much as possible,” said Purtell.
Purtell emphasized that this study cannot prove that fast-food consumption caused the lower academic growth observed in this study. However, by controlling for other possible explanations for this link, such as family background and what other food they ate, and by looking at change in achievement scores, the authors are confident fast food is explaining some of the difference in achievement gains over time.
In addition, because the study examined only changes in test scores between fifth and eighth grade it controls for all the early childhood factors that may affect test grades.
This study can’t say why fast-food consumption is linked to lower grades, she said. But other studies have shown that fast food lacks certain nutrients, especially iron, that help cognitive development. In addition, diets high in fat and sugar — similar to fast-food meals — have been shown to hurt immediate memory and learning processes.
Weight training appears key to controlling belly fat
Harvard School of Public Health
Boston, MA — Healthy men who did twenty minutes of daily weight training had less of an increase in age-related abdominal fat compared with men who spent the same amount of time doing aerobic activities, according to a new study by Harvard School of Public Health (HSPH) researchers and colleagues. Combining weight training and aerobic activity led to the most optimal results. Aerobic exercise by itself was associated with less weight gain compared with weight training.
The study appears online December 22, 2014 in Obesity.
“Because aging is associated with sarcopenia, the loss of skeletal muscle mass, relying on body weight alone is insufficient for the study of healthy aging,” said lead author Rania Mekary, a researcher in HSPH’s Department of Nutrition. “Measuring waist circumference is a better indicator of healthy body composition among older adults. Engaging in resistance training or, ideally, combining it with aerobic exercise could help older adults lessen abdominal fat while increasing or preserving muscle mass.”
Prior studies had been focused on a specific population (e.g. overweight or with type 2 diabetes) and were of short duration and had mixed results. The new study was long-term with a large sample of healthy men with a wide range of BMI (body mass index).
Mekary and colleagues studied the physical activity, waist circumference (in centimeters (cm)), and body weight of 10,500 healthy U.S. men aged 40 and over participating in the Health Professionals Follow-up Study between 1996 and 2008. Their analysis included a comparison of changes in participants’ activity levels over the 12-year period to see which activities had the most effect on the men’s waistlines. Those who increased the amount of time spent in weight training by 20 minutes a day had less gain in their waistline (-0.67 cm) compared with men who similarly increased the amount of time they spent on moderate-to-vigorous aerobic exercise (-0.33 cm), and yard work or stair climbing (-0.16 cm). Those who increased their sedentary behaviors, such as TV watching, had a larger gain in their waistline.
“This study underscores the importance of weight training in reducing abdominal obesity, especially among the elderly,” said Frank Hu, professor of nutrition and epidemiology at HSPH and senior author of the study. “To maintain a healthy weight and waistline, it is critical to incorporate weight training with aerobic exercise.”
Public Release: 22-Dec-2014
Scientists uncover new, fundamental mechanism for how resveratrol provides health benefits
The ingredient found in red wine activates ancient stress response
Scripps Research Institute
LA JOLLA, CA and JUPITER, FL–December 22, 2014–Scientists at The Scripps Research Institute (TSRI) have found that resveratrol, the red-wine ingredient once touted as an elixir of youth, powerfully activates an evolutionarily ancient stress response in human cells. The finding should dispel much of the mystery and controversy about how resveratrol really works.
“This stress response represents a layer of biology that has been largely overlooked, and resveratrol turns out to activate it at much lower concentrations than those used in prior studies,” said senior investigator Paul Schimmel, professor and member of the Skaggs Institute for Chemical Biology at TSRI.
“With these findings we have a new, fundamental mechanism for the known beneficial effects of resveratrol,” said lead author Mathew Sajish, a senior research associate in the Schimmel laboratory.
The discovery is reported in the advance online edition of Nature on December 22.
Resveratrol is a compound produced in grapes, cacao beans, Japanese knotweed and some other plants in response to stresses including infection, drought and ultraviolet radiation. It has attracted widespread scientific and popular interest over the past decade, as researchers have reported that it extended lifespan and prevented diabetes in obese mice and vastly increased the stamina of ordinary mice running on wheels.
More recently, though, scientists in this field have disagreed about the signaling pathways resveratrol activates to promote health, calling into question some of resveratrol’s supposed health benefits–particularly given the unrealistically high doses used in some experiments.
Outsiders to the Controversy
Schimmel and Sajish came to this controversy as outsiders. Schimmel’s laboratory is known for its work not on resveratrol but on an ancient family of enzymes, the tRNA synthetases. The primary and essential function of these enzymes is to help translate genetic material into the amino-acid building blocks that make proteins. But as Schimmel and others have shown since the late 1990s, tRNA synthetases have acquired an extensive set of added functions in mammals.
Earlier Xiang-Lei Yang, a TSRI professor in the Departments of Chemical Physiology and Cell and Molecular Biology and former member of Schimmel’s laboratory, began to find hints that a tRNA synthetase called TyrRS, which links the amino acid tyrosine to the genetic material that codes for it, can move to the cell nucleus under stressful conditions–apparently taking on a protective, stress-response role. Sajish noted that resveratrol appeared to have broadly similar stress-response properties and also resembled TyrRS’s normal binding partner tyrosine. “I began to see TyrRS as a potential target of resveratrol,” he said.
For the new study, Sajish and Schimmel put TyrRS and resveratrol together and showed with tests including X-ray crystallography that resveratrol does indeed mimic tyrosine, well enough to fit tightly into TyrRS’s tyrosine binding pocket. That binding to resveratrol, the team found, takes TyrRS away from its protein translation role and steers it to a function in the cell nucleus.
Tracking the resveratrol-bound TyrRS in the nucleus, the researchers determined that it grabs and activates the protein, PARP-1, a major stress response and DNA-repair factor thought to have a significance influence on lifespan. The scientists confirmed the interaction in mice injected with resveratrol. TyrRS’s activation of PARP-1 led, in turn, to the activation of a host of protective genes including the tumor-suppressor gene p53 and the longevity genes FOXO3A and SIRT6.
Compatible with Red Wine
The first studies of resveratrol in the early 2000s had suggested that it exerts some of its positive effects on health by activating SIRT1, also thought to be a longevity gene. But SIRT1‘s role in mediating resveratrol’s reported health-boosting effects has been questioned lately in terms of its particular role.
The team’s experiments showed, however, that the TyrRS-PARP-1 pathway can be measurably activated by much lower doses of resveratrol–as much as 1,000 times lower–than were used in some of the more celebrated prior studies, including those focused on SIRT1. “Based on these results, it is conceivable that moderate consumption of a couple glasses of red wine (rich in resveratrol) would give a person enough resveratrol to evoke a protective effect via this pathway,” Sajish said. He also suspects that effects of resveratrol that only appear at unrealistically high doses may have confounded some prior findings.
Why would resveratrol, a protein produced in plants, be so potent and specific in activating a major stress response pathway in human cells? Probably because it does much the same in plant cells, and probably again via TyrRS–a protein so fundamental to life, due to its linkage to an amino acid, that it hasn’t changed much in the hundreds of millions of years since plants and animals went their separate evolutionary ways. “We believe that TyrRS has evolved to act as a top-level switch or activator of a fundamental cell-protecting mechanism that works in virtually all forms of life,” said Sajish.
Whatever activity resveratrol naturally has in mammals may be an example of hormesis: the mild, health-promoting activation of a natural stress response. “If resveratrol brought significant benefits to mammals, they might have evolved a symbiotic relationship with resveratrol-producing plants,” Sajish said.
“We think this is just the tip of the iceberg,” said Schimmel. “We think there are a lot more amino-acid mimics out there that can have beneficial effects like this in people. And we’re working on that now.”
Schimmel and his laboratory also are searching for molecules that can activate the TyrRS stress response pathway even more potently than resveratrol does.
Public Release: 23-Dec-2014
Daily multivitamin improves pregnancy outcomes in South Asia, JAMA study suggests
Taking supplement containing 15 vitamins and minerals results in longer pregnancies and bigger, healthier babies
Johns Hopkins University Bloomberg School of Public Health
A multivitamin given daily to pregnant women in rural Bangladesh reduced pre-term births, increased infant birth weight and resulted in healthier babies overall, according to the large randomized trial conducted by Johns Hopkins Bloomberg School of Public Health researchers.
The findings, published in the Dec. 24 issue of JAMA, suggest that a supplement containing 15 essential micronutrients is superior to the current standard of care in many developing countries, which calls for pregnant women to take supplements containing iron and folic acid.
“Our study shows that women in undernourished societies should be given a multiple micronutrient supplement during pregnancy,” says study leader Keith P. West Jr., DrPH, George G. Graham Professor of Infant and Child Nutrition in the Department of International Health at the Johns Hopkins Bloomberg School of Public Health. “It increases birth size because the babies stay in the womb longer and when that happens they are born a little larger and better equipped to handle life outside the womb. There is clear evidence of benefit.”
Inadequate diets leading to poor nutrition are a serious public health problem in many parts of the world where many pregnant women lack micronutrients critical to the growth and development of their fetuses, setting these children back even before their lives outside the womb have begun.
For this study, a large research team in the Johns Hopkins JiVitA Project recruited roughly 45,000 pregnant women in rural Bangladesh beginning in December 2007, and assigned them to receive either a daily multivitamin or an iron-folic acid supplement. The women were followed through their pregnancies and, for those who gave birth, at one, three and six months after their children were born. There were roughly 14,000 live births in each group in the trial, with other pregnancies lost to miscarriage, abortion or stillbirth.
Those women who received the larger number of micronutrients were 15 percent less likely to give birth prematurely or prior to 37 weeks of gestation. Pre-term birth is a leading cause of infant mortality in many parts of the world. The babies born in the multivitamin group were 12 percent less likely to be born at a low birth weight (under 2.5 kg or 5 lbs, 8 oz.) and 11 percent less likely to be stillborn. On average, the infants born to mothers in the multivitamin group were born two to three days later than those in the iron-folic acid group, giving them more time to bulk up before birth, and were born an average of 55 grams (or roughly two ounces) larger.
West says that while infant mortality rates at six months of age were roughly the same in each group, the research suggests that girls born to mothers receiving the vitamin and mineral preparation may have survived better than girls whose mothers received only iron and folic acid. Of note: This did not happen in boys, requiring further data analysis to fully understand why.
“In countries like the United States, where there is already better vitamin and mineral nutrition, women often start taking micronutrient supplements as soon as they become pregnant, if not before,” says West, director of the Johns Hopkins Center for Human Nutrition. “But they don’t in the developing world. Vitamin and mineral supplements are more costly – probably several cents per tablet more – so in cultures where families make only a few dollars a day we need to be able to show that the investment is worthwhile in terms of having an impact on the health of mothers and their children. This study provides the needed evidence.”
Sugar molecule links red meat consumption and elevated cancer risk in mice
Neu5Gc, a non-human sugar found in red meat, promotes inflammation and cancer progression in rodents
University of California – San Diego
While people who eat a lot of red meat are known to be at higher risk for certain cancers, other carnivores are not, prompting researchers at the University of California, San Diego School of Medicine to investigate the possible tumor-forming role of a sugar called Neu5Gc, which is naturally found in most mammals but not in humans.
In a study published in the Dec. 29 online early edition of the Proceedings of the National Academy of Sciences, the scientists found that feeding Neu5Gc to mice engineered to be deficient in the sugar (like humans) significantly promoted spontaneous cancers. The study did not involve exposure to carcinogens or artificially inducing cancers, further implicating Neu5Gc as a key link between red meat consumption and cancer.
“Until now, all of our evidence linking Neu5Gc to cancer was circumstantial or indirectly predicted from somewhat artificial experimental setups,” said principal investigator Ajit Varki, MD, Distinguished Professor of Medicine and Cellular and Molecular Medicine and member of the UC San Diego Moores Cancer Center. “This is the first time we have directly shown that mimicking the exact situation in humans — feeding non-human Neu5Gc and inducing anti-Neu5Gc antibodies — increases spontaneous cancers in mice.”
Varki’s team first conducted a systematic survey of common foods. They found that red meats (beef, pork and lamb) are rich in Neu5Gc, affirming that foods of mammalian origin such as these are the primary sources of Neu5Gc in the human diet. The molecule was found to be bio-available, too, meaning it can be distributed to tissues throughout the body via the bloodstream.
The researchers had previously discovered that animal Neu5Gc can be absorbed into human tissues. In this study, they hypothesized that eating red meat could lead to inflammation if the body’s immune system is constantly generating antibodies against consumed animal Neu5Gc, a foreign molecule. Chronic inflammation is known to promote tumor formation.
To test this hypothesis, the team engineered mice to mimic humans in that they lacked their own Neu5Gc and produced antibodies against it. When these mice were fed Neu5Gc, they developed systemic inflammation. Spontaneous tumor formation increased fivefold and Neu5Gc accumulated in the tumors.
“The final proof in humans will be much harder to come by,” Varki said. “But on a more general note, this work may also help explain potential connections of red meat consumption to other diseases exacerbated by chronic inflammation, such as atherosclerosis and type 2 diabetes.
“Of course, moderate amounts of red meat can be a source of good nutrition for young people. We hope that our work will eventually lead the way to practical solutions for this catch-22.”
Public Release: 29-Dec-2014
Estrogen worsens allergic reactions in mice
NIH study may help explain gender disparity observed in people
NIH/National Institute of Allergy and Infectious Diseases
Estradiol, a type of estrogen, enhances the levels and activity in mice of an enzyme that drives life-threatening allergic reactions, according to researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). The study results may help explain why women frequently experience more severe allergic reactions compared to men. Furthermore, the results reaffirm the importance of accounting for gender in the design of animal experiments.
Anaphylaxis is an allergic reaction triggered by food, medication or insect stings and bites. Immune cells, particularly mast cells, release enzymes that cause tissues to swell and blood vessels to widen. As a result, skin may flush or develop a rash, and in extreme cases, breathing difficulties, shock or heart attack may occur. Clinical studies have shown that women tend to experience anaphylaxis more frequently than men, but why this difference exists is unclear.
In the current study, NIAID researchers found that female mice experience more severe and longer lasting anaphylactic reactions than males. Instead of targeting immune cells, estrogen influences blood vessels, enhancing the levels and activity of endothelial nitric oxide synthase (eNOS), an enzyme that causes some of the symptoms of anaphylaxis. When the researchers blocked eNOS activity, the gender disparity disappeared. In addition, giving estrogen-blocking treatments to female mice reduced the severity of their allergic responses to a level similar to those seen in males.
While the study has identified a clear role for estrogen and eNOS in driving severe anaphylactic reactions in female mice, more work is needed to see if the effects are similar in people and may be applied toward future preventive therapies.