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Author: Sima

Published on Leave a comment on Can Eating A Vegetarian Diet Lower Blood Pressure?

Can eating a vegetarian diet lower blood pressure? Both this review and other reviews of studies say YES, that those following vegetarian diets have a lower prevalence of hypertension. Overall, the mean prevalence of hypertension was 21% in those consuming a vegetarian diet and 29% in those consuming a nonvegetarian diet (the differences varied between studies).Those following a vegetarian diet also tended to have a healthier lifestyle. As the researchers point out: blood pressure medicine lowers blood pressure for one day, while lifestyle changes (diet, exercise, not smoking, limiting or avoiding alcohol) can lower blood pressure for life. From Medscape:

Vegetarian Diet: A Prescription for High Blood Pressure?

Hypertension is one of the most costly and poorly treated medical conditions in the United States and around the world. Consequences of hypertension include morbidity and mortality related to its long-term effects, which include stroke, myocardial infarction, renal failure, limb loss, aortic aneurysm, and atrial fibrillation, among many others. Although there is an armamentarium of medications to treat hypertension, we do little for prevention. In this review we examine the relationship between vegetarian and nonvegetarian diets and the prevalence of hypertension. 

Current nonpharmacologic treatments include: physical activity (≥ 30 minutes of moderate-intensity activity on most days of the week); smoking cessation; dietary modification (lower sodium, increased potassium; mainly plant-based foods; low-fat foods; reduced-fat dairy products; moderate amounts of lean unprocessed meats, poultry, and fish; and moderate amounts of polyunsaturated and monounsaturated fats, such as olive oil); weight reduction; management of stress; and limited alcohol consumption.

It is well known that hypertension is modulated by dietary influences. In this review we examine vegetarian, vegan, and nonvegetarian (omnivore) diets and prevalence of hypertension among these dietary populations. A vegetarian diet (ie, lacto/ovo-vegetarian) includes plant foods, dairy products, and eggs (excludes all meat, such as turkey, beef, poultry, seafood, bacon, etc.). A vegan diet is similar to vegetarian, except it further excludes dairy products and eggs (no animal or animal products). On the other hand, an omnivore diet (referred to as nonvegetarians throughout this study) includes both plant and animal foods and products.....The majority of studies included in this review addressed vegetarians and vegans as a single group (vegetarians), whereas others differentiated them. Vegetarian diets are known to be low in saturated fat and cholesterol, high in fiber, low in sodium, and high in potassium. These key elements have been shown to correlate with lower incidence of cancer, heart disease, and other chronic diseases, such as diabetes type II, hypertension, and hyperlipidemia.

The exact percentage of those following a vegetarian or vegan diet in the US is unknown; however, a 2014 study found that 221 of 11,399 adult respondents, from a group generally representing the demographics of the US, identified as vegan (0.5%), vegetarians (1.5%), or meat-eaters (98%). The prevalence of hypertension in the US in 2011 was roughly 33.8%.

The mean prevalence of hypertension in those consuming a vegetarian diet was 21% and 29% in those consuming a nonvegetarian diet. The overall prevalence of hypertension among vegetarians was 33% lower than nonvegetarian diets. These data support the hypothesis of a decreased prevalence of hypertension in those maintaining a vegan or vegetarian diet versus a nonvegetarian diet, in cross-sectional, cohort, and case-control studies, and in those consuming a vegan or vegetarian diet according to an experimental dietary change. The blood pressure benefit is noted to disappear in those reverting back to a nonvegetarian diet. 

Overall, these findings support previous reviews and meta-analyses of vegetarian and nonvegetarian diets and blood pressure. A recent meta-analysis that identified 39 studies with 21,915 participants concluded vegetarian diets were associated with a drop in mean systolic (-5.9 mm Hg) and diastolic (-3.5 mm Hg) blood pressures when compared with nonvegetarians. Other reviews had similar conclusions, showing that vegetarians have a lower blood pressure compared with nonvegetarians. Of the studies that included a vegan diet separate from other vegetarians (eg, lacto/ovo), the data show a significantly lower prevalence of hypertension when compared with nonvegetarians and other vegetarians. However, limited research has been conducted on strict, consistent vegan diets.

There are possible rationalizations for the observed associations between diet and hypertension. First, vegetarians have a lower rate of smoking tobacco. Smoking can increase blood pressure acutely and chronically over time.....Second, vegetarians tend to drink less alcohol compared with nonvegetarians. Alcohol, specifically ≥ 2 drinks/day, increases blood pressure by causing vasodilation, followed by a compensatory increase in blood pressure.....Further, vegetarians have a lower mean BMI when compared with nonvegetarians, which means a lower overall weight....Fourth, vegetarians tend to exercise more than nonvegetarians. Vegetarians reported a greater incidence of physical activity of ≥ 30 minutes of moderate to vigorous activity per day.

A limitation of this study is that it remains unclear whether vegetarians are more health conscious and therefore live healthier lives, or whether a predominant diet of fruits and vegetables is a basis for lower blood pressure.

Published on Leave a comment on The Longer Overweight, the Greater A Woman’s Cancer Risk

Yikes! A good reason to lose weight now rather than years from now, and the importance of not ignoring a weight gain (you know, over the years as the pounds slowly creep up). The researchers found that for every 10 years of being overweight as an adult, there was an associated 7% increase in the risk for all obesity-related cancers. The degree of overweight (dose-response) during adulthood was important in the risk of developing cancer, especially for endometrial cancer. This study just looked at postmenopausal women, so it is unknown if it applies to men. From Medscape:

Longer Duration of Overweight Increases Cancer Risk in Women

A longer duration of being overweight during adulthood significantly increased the incidence of all cancers that are associated with obesity, a new study in postmenopausal women has concluded. The large population-based study was published August 16 in PLoS Medicine.

Dr Arnold and colleagues found that for every 10 years of being overweight as an adult, there was an associated 7% increase in the risk for all obesity-related cancers. The risk was highest for endometrial cancer (17%) and kidney cancer (16%). For breast cancer, the increased risk was 5%, but no significant associations were found for rectal, liver, gallbladder, pancreatic, ovarian, and thyroid cancer.

When the authors took into account the degree of excess weight over time, the risks were further increased, and there were "clear dose-response relationships," they note. Again, the risk was highest for endometrial cancer. For each additional decade spent with a body mass index (BMI) that was 10 units above normal weight, there was a 37% increase in the risk for endometrial cancer.

Study Details: The researchers used data from the huge American Women's Health Initiative (WHI) trial of postmenopausal women (aged 50 to 79 years at time of study enrollment). For this analysis, the team focused on a cohort of 73,913 postmenopausal women. During a mean follow-up of 12.6 years, 6301 obesity-related cancers were diagnosed. About 40% (n = 29,770) of women in the cohort were never overweight during their adult life....Women who were ever overweight were on average overweight for about 30 years, while those who were ever obese had been so for an average of 20 years. The authors found that the risk of being diagnosed with an obesity-related cancer rose for every 10 years of being overweight.

Published on Leave a comment on Overdiagnosed and Overtreated For Thyroid Cancer

The problem of overdiagnosis and overtreatment has been discussed in a number of posts on this site. And back in April 15, 2016 I posted that a type of noninvasive thyroid cancer had just been reclassified as a noncancer. Now a study in the prestigious New England Journal of Medicine finds that looking at 12 countries (including the USA): "Overall, we estimate that more than 470,000 women and 90,000 men may have been overdiagnosed with thyroid cancer over two decades in these 12 countries..."

The researchers further state that the "vast majority" of these patients received a diagnosis of small, low-risk papillary carcinomas, and they underwent surgery and other treatments, but these interventions have not shown "benefits in terms of improved survival". In fact, studies show that watchful waiting is just as effective. From Medscape:

Thyroid Cancer Overdiagnosis in Half a Million Patients

A large fraction of thyroid cancer cases represent overdiagnoses, and at least half a million patients, most of them women, may have received unnecessary surgery and other cancer treatments, say researchers from the the International Agency for Research on Cancer (IARC), in Lyons, France.

Their warning about an epidemic of thyroid cancer overdiagnosis comes from an analysis of cancer registry data from 12 countries published August 17 in the New England Journal of Medicine . Salvatore Vaccarella, PhD, and colleagues at the IARC estimate that more than 470,000 women and 90,000 men may have been overdiagnosed withthyroid cancer in 12 "high-income" countries (Australia, Denmark, England, Finland, France, Italy, Japan, Norway, Republic of Korea, Scotland, Sweden, and the United States) from 1987 to 2007.

Most of these thyroid cancers were small, low-risk papillary carcinomas, they note. The "vast majority" of these patients underwent total thyroidectomy, and a "high proportion" also received neck lymph-node dissection and radiotherapy, but these interventions do not have "proven benefits in terms of improved survival," the researchers point out...."However, if we take the most recent available period, 2003 - 2007, as typical of current practice, we estimate that overdiagnosis in women accounts for 90% of thyroid-cancer cases in South Korea; 70 to 80% in the United States, Italy, France, and Australia; and 50% in Japan, the Nordic countries, and England and Scotland."

The overdiagnosis is blamed on increasing medical surveillance and the introduction of new diagnostic techniques, such as neck ultrasonography (since the 1980s) and, more recently, CTscanning and MRI. This new technology has led to the detection of a large number of indolent, nonlethal diseases that exist in abundance in the thyroid gland of healthy people of any age, the researchers comment, adding that most of these tumors are very unlikely to cause symptoms or death....."It is fair to say that the large number of thyroid cancers being diagnosed represent an epidemic of diagnosis, or an epidemic of medical testing, rather than an epidemic of true disease."

These results also mean that most patients are receiving treatment that does not benefit them and that subjects them to risks of injury to the voice, permanent hypoparathyroidism, as well as the attendant risks of radioactive iodine treatment, he pointed out.  

The researchers caution against systematic screening for thyroid cancer and overtreatment of nodules <1 cm. "Watchful-waiting approaches should be considered a research priority and a preferable option for patients with low-risk papillary thyroid cancers," they say. Studies from Japan suggest that immediate surgery and watchful waiting are equally effective in preventing mortality, Dr Vaccarella said. One study showed that of 1235 patients with papillary microcarcinomas, only 3.5% experienced clinical progression of disease during a 75-month follow-up, and there were no deaths.

At Memorial Sloan Kettering Cancer Center, active surveillance has been offered to patients with low-risk, small, intrathyroidal cancers for several years, Dr Morris said. "Our results have mirrored the Japanese results, and fewer than 5% of patients end up showing any signs of tumor growth under close observation," he said.

Published on Leave a comment on Seafood, DHA Levels, and the Aging Brain

 Eating several servings of seafood (especially fish) weekly has beneficial health effects throughout life, and now research finds another benefit in older adults. Seafood contains both EPA and DHA, which are two types of omega-3 fatty acids. DHA or docosahexanoic acid has "neuroprotective qualities" and is found in both the gray and white matter of the brain. Higher DHA levels (measured in the blood) was associated with better memory, less brain atrophy (better brain volume), and fewer amyloid plaques (which are associated with Alzheimer's) in cognitively healthy older adults. From Medscape:

Higher Serum DHA Linked to Less Amyloid, Better Memory

New research supports neuroprotectant effects of docosahexaenoic acid (DHA) in the aging brain. In a small cross-sectional study of cognitively healthy older adults, higher serum DHA levels were associated with less cerebral amyloidosis, better memory scores, and less regional brain atrophy.

"The interesting finding was the association of low serum DHA levels with cerebral amyloidosis (amyloid plaques) in older adults without evidence of dementia," Hussein N. Yassine, MD, Department of Medicine, University of Southern California, Los Angeles, told Medscape Medical News. "This association was predominantly driven by persons at the lowest quartile of serum DHA levels who likely have limited intake of seafood." "This study adds to the existing evidence on the benefit of seafood consumption on [Alzheimer's disease] AD risk factors," Dr Yassine added.

The study was published online August 8 in JAMA Neurology. In a linked editorial, Joseph F. Quinn, MD, Department of Neurology, Oregon Health and Science University, Portland, notes that DHA is "the most abundant polyunsaturated fatty acid in the brain, playing an important structural role in synapses while also modulating a number of signaling pathways. "Brain DHA levels are also modulated by dietary intake, so it is plausible for dietary DHA to alter brain concentrations and affect downstream targets including brain pathology and function."

Dr Yassine and colleagues assessed serum DHA levels, measures of amyloid burden based on positron emission tomography with Pittsburgh compound B, brain volume, and neuropsychological test scores in 61 adults without dementia in the Aging Brain Study.

They found that serum DHA levels (percentage of total fatty acids) were 23% lower in those with cerebral amyloidosis relative to those without. Serum DHA levels were inversely correlated with brain amyloid load, independent of age, sex, years of education, and apolipoprotein E genotype. They also noted a positive correlation between serum DHA levels and brain volume in several subregions affected by AD, in particular the left subiculum and the left entorhinal volumes.

Clinically, there was a significant association between serum DHA levels and nonverbal memory. This association persisted after adjustment for age but not after adjustment for apolipoprotein E genotype. Serum DHA levels were not associated with measures of global cognition, executive function, or verbal memory scores.

Published on Leave a comment on Peanut Allergies Can Be Successfully Treated In Young Children

Yes! Treating young children who have peanut allergies with doses of peanut protein (oral immunotherapy or OIT) for one month works in treating the peanut allergies in the overwhelming majority of young children in an important study. Several studies have now shown that early exposure to nuts is important for prevention of nut allergies, and in this study the researchers showed that both lower and higher dose oral immunotherapy works in treating nut allergies in young children (9 to 36 months of age). Note that this is a paradigm change - before this the thinking was avoid, avoid, avoid for the child to not get or to not worsen the allergy (whether nuts or animals), but now it's early exposure is good in preventing and treating allergies. From Futurity:

Can therapy before 3 wipe out a peanut allergy?

Preschool children with a peanut allergy were able to start eating peanuts after taking part in oral immunotherapy, a new study shows. The findings confirm and extend previous results that show oral immunotherapy (OIT) can protect children from potentially life-threatening anaphylaxis caused by peanut exposure.

The phase two clinical trial results, published online in the Journal of Allergy and Clinical Immunology, show that one month after completing the OIT protocol, almost 80 percent of trial participants achieved “sustained unresponsiveness,” the highest rate yet reported.

“These findings, if confirmed in larger studies, could transform the care of peanut-allergic children early in life,” says Brian P. Vickery, lead investigator of the trial and assistant professor of pediatrics at the University of North Carolina at Chapel Hill. Approximately three million people in the United States report having allergies to peanuts and tree nuts. According to a study released in 2013 by the Centers for Disease Control and Prevention, food allergies among children increased approximately 50 percent between 1997 and 2011.

The initial allergic reaction to peanuts commonly occurs within the first year or two of life, and the condition persists in 80 percent of affected patients, placing them at life-long risk of anaphylaxis. Based on other studies suggesting that peanut allergies strengthen over time, researchers enrolled 40 peanut-allergic children aged 9 to 36 months in the trial, the first study to specifically target children under the age of three.

Children were randomly assigned to high-dose peanut OIT with a target daily dose of 3,000 milligrams of peanut protein or a low-dose regimen with a target dose of 300 milligrams. The trial was double-blinded. Participants took 3,000 mg of study protein, but for the low-dose group, 2,700 mg of placebo was added to the OIT medication. As in previous studies, nearly all participants experienced some side effects, most of which were mild and required little or no treatment.

After receiving OIT for 29 months on average, participants abstained from peanut exposure for four weeks before undergoing a final peanut challenge—where participants ingest a small amount of peanut in a controlled setting. If the challenge is successful, then doctors reintroduce normal amounts of peanuts—such as in a peanut butter and jelly sandwich—into the diets of participants. After the four-week period, nearly 80 percent of children in both the high- and low-dose groups consumed peanut with no allergic response and achieved sustained unresponsiveness.

The OIT-treated children were compared with a matched control group of 154 peanut-allergic children who avoided peanut. The OIT-treated children experienced beneficial changes in their immune responses to peanut and were 19 times more likely to successfully incorporate peanut into their diets. 

Published on Leave a comment on Lifestyle Factors Influence Protein Buildups Linked to Alzheimer’s

  Again, another study showing the importance of lifestyle factors in the development of protein buildups in the brain that are associated with the onset of Alzheimer's disease. Specifically, the study found that each one of several lifestyle factors—a healthy body mass index, physical activity and a Mediterranean diet, were linked to lower levels of plaques and tangles on brain scans in people who already had mild memory changes, (but not dementia). Other posts discussing Mediterranean diet and brain health (brain volume, etc.) are here, here, and here. Activity levels and brain health posts are here, here, and here. From Medical Xpress:

Diet and exercise can reduce protein build-ups linked to Alzheimer's

A study by researchers at UCLA's Semel Institute for Neuroscience and Human Behavior has found that a healthy diet, regular physical activity and a normal body mass index can reduce the incidence of protein build-ups that are associated with the onset of Alzheimer's disease.

In the study, 44 adults ranging in age from 40 to 85 (mean age: 62.6) with mild memory changes but no dementia underwent an experimental type of PET scan to measure the level of plaque and tangles in the brain. Researchers also collected information on participants' body mass index, levels of physical activity, diet and other lifestyle factors. Plaque, deposits of a toxic protein called beta-amyloid in the spaces between nerve cells in the brain; and tangles, knotted threads of the tau protein found within brain cells, are considered the key indicators of Alzheimer's.

The study found that each one of several lifestyle factors—a healthy body mass index, physical activity and a Mediterranean diet—were linked to lower levels of plaques and tangles on the brain scans. (The Mediterranean diet is rich in fruits, vegetables, legumes, cereals and fish and low in meat and dairy, and characterized by a high ratio of monounsaturated to saturated fats, and mild to moderate alcohol consumption.)

"The fact that we could detect this influence of lifestyle at a molecular level before the beginning of serious memory problems surprised us," said Dr. David Merrill, the lead author of the study, which appears in the September issue of the American Journal of Geriatric Psychiatry.

Earlier studies have linked a healthy lifestyle to delays in the onset of Alzheimer's. However, the new study is the first to demonstrate how lifestyle factors directly influence abnormal proteins in people with subtle memory loss who have not yet been diagnosed with dementia, Merrill said. Healthy lifestyle factors also have been shown to be related to reduced shrinking of the brain and lower rates of atrophy in people with Alzheimer's."The study reinforces the importance of living a healthy life to prevent Alzheimer's, even before the development of clinically significant dementia," Merrill said. 

Published on Leave a comment on More Problems With BPA, BPS, and “BPA Free”

Two recent articles about BPA (bisphenol A), BPS (bisphenol B), and the "BPA-free" label  - one a study, and one a review article. The "BPA-free" label unfortunately means the product contains a product similar to BPA (typically BPS) and with the same problems as BPA. Both articles discuss the accumulating health reasons to try to avoid these endocrine disruptors. Which is really , really tough to do given that plastics are all around us and used by us every day.

From Science Daily: Prenatal BPA exposure linked to anxiety and depression in boys

Boys exposed prenatally to a common chemical used in plastics may be morelikely to develop symptoms of anxiety and depression at age 10-12. The new study by researchers at the Columbia Center for Children's Environmental Health (CCCEH) within the Mailman School of Public Health examined early life exposure to the chemical Bisphenol A (BPA). Results are published in the journal Environmental Research.

BPA is a component of some plastics and is found in food containers, plastic water bottles, dental sealants, and thermal receipt paper. In the body, BPA is a synthetic estrogen, one of the class of chemicals known as "endocrine disruptors." The Columbia researchers, led by Frederica Perera, PhD, DrPH, director of CCCEH, previously reported that prenatal exposure to BPA was associated with emotionally reactive and aggressive behavior, and more symptoms of anxiety and depression in boys at age 7-9.

Perera and her co-investigators followed 241 nonsmoking pregnant women and their children, a subset of CCCEH's longstanding urban birth cohort study in New York City, from pregnancy through childhood....Researchers controlled for factors that have been previously associated with BPA exposure levels, including socioeconomic factors. After separating the data by sex, they found that boys with the highest levels of prenatal exposure to BPA had more symptoms of depression and anxiety than boys with lower levels of prenatal exposure to BPA; no such associations were found in girls.

From Endocrine News: Warning Signs: How Safe Is “BPA Free?”

While stickers are showing up declaring certain products “BPA Free,” that doesn’t mean they’re necessarily safe. Could bisphenol S be even worse than the compound it is supposed to be replacing? 

Human exposure to BPA is as ubiquitous as the stickers showing up now that proclaim products BPA free. The chemical used to make plastic has been linked to all kinds of reproductive issues, and even thought to play a role in the development of obesity and cardiovascular events, so industry is taking some steps to correct the problem (after much wailing and gnashing of teeth on their part). These stickers read “BPA FREE” and “NON-TOXIC PLASTIC” in bold letters and usually feature leaves and a green motif, the implication being that these products are safe and healthy. 

But “BPA free” does not mean “EDC free” [endocrine disruptor free] and many products now contain bisphenol S as a substitute for BPA. BPS is a similar chemical and has been found in everything from canned soft drinks to receipt paper to baby bottles. (The FDA banned BPA in baby bottles.) It’s been found in indoor dust samples and is beginning to show up in human urine, and it has been reported to be less biodegradable than BPA. Animal studies have implicated BPS in impaired offspring development. And the production of BPS is increasing annually.

“Recent studies testing BPS and comparing it to BPA show that BPS is as bad, if not worse, than BPA as an EDC,” says Andrea Gore, PhD, professor and Vacek Chair of Pharmacology at the University of Texas in Austin, and editor-in-chief of Endocrinology. “’BPA free’ can give consumers a false sense of security about the product.”

According to Kimberly H. Cox, a postdoctoral fellow studying reproductive endocrinology at Massachusetts General Hospital in Boston, the effects of BPA and BPS are subtler than say, PCBs or pesticides, where exposures came at high levels, with devastating effects. The effects of BPA and BPS depend on the timing, length, and dose of exposure, and numerous studies have shown that there are effects on the reproductive system, for example, at doses of BPA much lower than what has been determined as a “safe” exposure by the EPA. And now there also seem to be effects of BPS on the development of the reproductive system, as well as the brain regions that control reproduction.

“When endocrinologists talk about BPA, they frequently describe it as estrogenic – and do not point out the other endocrine systems that are being altered, such as thyroid hormone,” Wayne says. “Our paper emphasizes that BPA and BPS are activating both estrogenic and thyroid hormone pathways. This suggests that EDCs are having much broader effects on health and disease than just mimicking estrogens (which is bad enough).”

Published on Leave a comment on Farm Animal Exposure and Asthma In Children

Earlier posts discussed research that showed that farm and animal (pets such as dogs) exposures in the first year of life is protective against allergies and asthma (lowers the risk of developing them). New research examined this further by looking at Amish and Hutterite groups - looking at not just "farm life", but whether children had much exposure to farm animals. The Amish have close exposure to farm animals (traditional farming methods), but the Hutterites don't (communal highly industrialized farming). Both groups studied had similar lifestyles (drank raw milk, breastfeeding, little exposure to smoking), but both groups did not have indoor pets ("taboos against indoor pets"). Thus farming methods were important for exposures to animals and their microbes.

The researchers said: "The importance of environmental exposures in the development of asthma is most exquisitely illustrated by epidemiologic studies conducted in Central Europe that show significant protection from asthma and allergic disease in children raised on traditional dairy farms. In particular, children’s contact with farm animals and the associated high microbial exposures4,5have been related to the reduced risk." Traditional farming exposed the children to an environment rich in microbes, and these children had very low rates of asthma and "distinct immune profiles that suggest profound effects on innate immunity." Once again, note the importance of microbes in the development of the immune system. From Science Daily:

Growing up on an Amish farm protects children against asthma by reprogramming immune cells

By probing the differences between two farming communities -- the Amish of Indiana and the Hutterites of South Dakota -- an interdisciplinary team of researchers found that specific aspects of the Amish environment are associated with changes to immune cells that appear to protect children from developing asthma. In the Aug. 4, 2016, issue of The New England Journal of Medicine, the researchers showed that substances in the house dust from Amish, but not Hutterite, homes were able to engage and shape the innate immune system (the body's front-line response to most microbes) in young Amish children in ways that may suppress pathologic responses leading to allergic asthma.

The Amish and Hutterite farming communities in the United States, founded by immigrants from Central Europe in the 18th and 19th centuries, respectively, provide textbook opportunities for such comparative studies. The Amish and the Hutterites have similar genetic ancestry. They share similar lifestyles and customs, such as no television and a Germanic farming diet. They have large families, get childhood vaccinations, breastfeed their children, drink raw milk and don't allow indoor pets.

The communities, however, are distinct in two important ways. Although both groups depend on agriculture, their farming practices differ. The Amish have retained traditional methods. They live on single-family dairy farms and rely on horses for fieldwork and transportation. In contrast, the Hutterites live on large communal farms. They use modern, industrialized farm machinery. This distances young Hutterite children from the constant daily exposure to farm animals. The other striking difference is what Ober calls a "whopping disparity in asthma." About 5 percent of Amish schoolchildren aged 6 to 14 have asthma. This is about half of the U.S. average (10.3%) for children aged 5 to 14, and one-fourth of the prevalence (21.3%) among Hutterite children.

To understand this disparity, the researchers studied 30 Amish children 7 to 14 years old, and 30 age-matched Hutterite children. They scrutinized the children's genetic profiles, which confirmed the remarkable similarities between Amish and Hutterite children. They compared the types of immune cells in the children's blood, collected airborne dust from Amish and Hutterite homes and measured the microbial load in homes in both communities.

The first gee-whiz moment came from the blood studies. These revealed startling differences between the innate immune response from the Amish and Hutterites. "The Amish had more and younger neutrophils, blood cells crucial to fight infections, and fewer eosinophils, blood cells that promote allergic inflammation," said study co-author, immunologist Anne Sperling, PhD, associate professor of medicine at the University of Chicago. Gene expression profiles in blood cells also revealed enhanced activation of key innate immunity genes in Amish children.

The second eureka moment came from experiments using mice. When study co-author, immunologist Donata Vercelli, MD, professor of cellular and molecular medicine and associate director of the Asthma and Airway Disease Research Center at the University of Arizona, exposed mice to house-dust extracts, she found the airways of mice that received Amish dust were protected from asthma-like responses to allergens. In contrast, mice exposed to Hutterite house dust were not protected.

What was different? Dust collected from Amish homes was "much richer in microbial products," the authors note, than dust from Hutterite homes. "Neither the Amish nor the Hutterites have dirty homes," Ober explained. "Both are tidy. The Amish barns, however, are much closer to their homes. Their children run in and out of them, often barefoot, all day long. There's no obvious dirt in the Amish homes, no lapse of cleanliness. It's just in the air, and in the dust."

To better understand how asthma protection was achieved, the researchers used mice that lack MyD88 and Trif, genes crucial for innate immune responses. In these mice, the protective effect of the Amish dust was completely lost. "The results of the mouse experiments conclusively prove that products from the Amish environment are sufficient to confer protection from asthma, and highlight the novel, central role that innate immunity plays in directing this process," Vercelli said.

Published on Leave a comment on Exercise Can Lead To Misdiagnosis of Heart Disease

 The last post pointed out that the importance of high levels of physical activity or exercise in reducing the risk of 5 diseases. Now a study points out that all this exercise (starting at about 3 to 5 hours of exercise per week) can result in the heart becoming enlarged from all this exercise ("athlete's heart"), and that this is totally normal and healthy. The researchers also stressed that doctors should be aware that athlete's heart or "exercise-related cardiac remodeling" can occur not only in professional athletes, but also in those engaging in moderate levels of exercise, and that it not be misdiagnosed as heart disease. From Science Daily:

Regular exercise can lead to heart disease misdiagnosis

Scientists have shown that people who exercise for even a few hours each week can enlarge their hearts. This is a normal and beneficial response to exercise, but until now has only been recognised in athletes. The researchers say that doctors should now consider an individual's activity level before diagnosing common heart conditions.

"It's well known that the hearts of endurance athletes adapt in response to exercise, a phenomenon called 'athlete's heart'. This study is the first to show that healthy adults who do regular exercise may also develop enlarged hearts. As a result, there's a risk that some active adults could be misdiagnosed with heart disease," says Declan O'Regan, of the MRC Clinical Sciences Centre, based at Imperial College London, and one of the lead scientists on the research. The findings were published today in Circulation: Cardiovascular Imaging.

Scientists have not previously known the extent to which the hearts of healthy people adapt to the demands of moderate exercise. Over 1000 people took part in this study, making it one of the largest of its kind. Participants selected one of four possible categories that best represented their activity level over the past year, according to how many hours of exercise they did each week. Around one third of participants reported doing three to five hours of exercise, and the scientists found that one in five of these people had developed an enlarged heart as a result. Similar adaptations were seen in almost half of those who reported doing more than five hours of exercise.

The findings suggest that above a threshold of three hours, the more exercise you do, the more your heart is likely to adapt, and the more the exercise, the more pronounced the changes. "Going to the gym frequently increases the thickness of your heart muscle and the volume of your heart chambers, particularly the right ventricle. It's a completely normal, healthy response. It shouldn't be misdiagnosed as being heart disease," says O'Regan. These adaptations allow the heart to pump more blood, which helps to supply exercising muscles with the oxygen and nutrients they need. Changes to the heart's thickness and volume happen in tandem, and this distinguishes them from the changes seen in disease, which occur in isolation.

Today, doctors across the world use a standard of set values to see if the thickness and volume of a person's heart fall into the healthy or abnormal range. This helps to ensure consistency between different hospitals. According to O'Regan, the data that underpins these ranges comes from a relatively small study with people who were mainly sedentary. He says, "In this latest study, we looked at a much larger and broader group of people. We found that more people reported being active than had done in previous studies. Our recommendations reflect this growing participation in exercise.".....And this interesting research shows that even moderate physical activity is associated with changes in the heart's size and shape, which are visible on a cardiac MRI.

Published on Leave a comment on Really Increase Activity Level to Reduce Risk of 5 Diseases

Get active, really active, to reduce your risk for 5 diseases: breast cancer, colon cancer, heart disease, and ischemic stroke. Instead of the 150 minutes of brisk walking or 75 minutes per week of running (which is equal to the 600 metabolic equivalent (MET) minutes now recommended by the World Health Organization), this study found that much more exercise is needed for best health results.

This study (which was a review and analysis of 174 studies) found that there is a dose-response effect, with the most reduction in the risk of the 5 conditions by getting 3000 to 4000 MET minutes per week. This sounds like a lot, but the researchers  point out that this can be achieved by incorporating exercise into your daily routines. The researchers write: "A person can achieve 3000 MET minutes/week by incorporating different types of physical activity into the daily routine—for example, climbing stairs 10 minutes, vacuuming 15 minutes, gardening 20 minutes, running 20 minutes, and walking or cycling for transportation 25 minutes on a daily basis would together achieve about 3000 MET minutes a week."

So start thinking creatively about how to increase exercise or activity into your daily life, especially moderate or vigorous intensity activity. For example, park your car far from the store door, or better yet, bicycle or walk to the store from home. From Medscape:

Get Moving: High Physical-Activity Level Reduces Risk of 5 Diseases

High levels of physical activity can reduce the risk for five major diseases, including type 2 diabetes, new research shows. Findings from the systematic review and meta-analysis were published online ....The data, from a total 174 studies comprising 149,184,285 total person-years of follow-up, suggest that the more total regular daily physical activity one engages in — including recreation, transportation, occupational activity, and/or daily chores — the lower the risks for breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke.

However, significant reductions in those conditions were seen only with total activity levels considerably higher than the minimum 600 metabolic equivalent (MET) minutes per week recommended by the World Health Organization for health benefits. That 600 METs equates to about 150 minutes/week of brisk walking or 75 minutes/week of running. (A MET is defined as the ratio of the metabolic rate during that activity to the metabolic rate when resting.) Risks of the five conditions dropped significantly with an increase in MET minutes per week from 600 to 3000 to 4000, with less additive benefit seen above that level.

For reference, the authors say, "a person can achieve 3000 MET minutes/week by incorporating different types of physical activity into the daily routine — for example, climbing stairs 10 minutes, vacuuming 15 minutes, gardening 20 minutes, running 20 minutes, and walking or cycling for transportation 25 minutes on a daily basis would together achieve about 3000 MET minutes a week." "This amount might seem a bit large, but this is about total activity across all domains of life.…For people who currently don't exercise, clinicians could encourage them to incorporate physical activity into their daily routines, [such as] turning household chores into exercise. 

Another recent meta-analysis of trials involving more than one million individuals indicated that an hour of moderate-intensity activity, such as brisk walking or cycling, offsets the health risks of 8 hours of sitting. The message that physical inactivity is a killer — leading to 5.3 million premature deaths annually worldwide, which is as many as caused by smoking and twice as many as associated with obesity, has been emerging over the past few years, with warnings that "sitting is the new smoking."

This new research is the first meta-analysis to quantify the dose-response association between total physical activity across all domains and the risk of five chronic diseases. The 174 prospective cohort studies included 35 for breast cancer, 19 for colon cancer, 55 for diabetes, 43 for ischemic heart disease, and 26 for ischemic stroke. (Some included more than one end point.)....Higher levels of total physical activity were associated with lower risks of all five outcomes.

With the development of diabetes, for example, compared with no physical activity, those with 600 MET minutes per week (the minimum recommended level of activity) had a 2% lower risk. That risk reduction jumped by an additional 19% with an increase from 600 to 3600 METs/week. Gains were smaller above that, with the increase of total activity from 9000 to 12,000 MET minutes/week yielding only an additional 0.6% diabetes reduction.

Overall, compared with insufficiently active individuals (total activity < 600 MET minutes/week), the risk reduction for those in the highly active category (≥ 8000 MET minutes/week) was 14% for breast cancer; 21% for colon cancer; 28% for diabetes; 25% for ischemic heart disease; and 26% for ischemic stroke. 

Credit: Medscape