Yogurt may help to lower pre-cancerous bowel growth risk in men

Eating two or more weekly servings of yogurt may help to lower the risk of developing the abnormal growths (adenomas) which precede the development of bowel cancer -- at least in men -- finds research published online in the journal Gut.

The observed associations were strongest for adenomas that are highly likely to become cancerous, and for those located in the colon rather than in the rectum, the findings indicate.

Previously published research has suggested that eating a lot of yogurt might lower the risk of bowel cancer by changing the type and volume of bacteria in the gut (microbiome).

But it's not been clear whether yogurt intake might also be associated with a lower risk of pre-cancerous growths, known as adenomas.

The researchers therefore looked at the diets and subsequent development of different types of adenoma among 32,606 men who were part of the Health Professionals Follow Up Study and 55,743 women who were part of the Nurses Health Study.

All the study participants had had a lower bowel endoscopy -- a procedure that enables a clinician to view the inside of the gut -- between 1986 and 2012. And every four years, they provided detailed information on lifestyle and diet, including how much yogurt they ate.

During the study period, 5811 adenomas developed in the men and 8116 in the women.

Compared with men who didn't eat yogurt, those who ate two or more servings a week were 19% less likely to develop a conventional adenoma.

This lower risk was even greater (26%) for adenomas that were highly likely to become cancerous, and for those located in the colon rather than in the rectum.

While no obvious association was seen for men with a potentially more dangerous type of adenoma (serrated), a trend towards reduced risk was seen for those measuring 1 or more cm, which is considered to be large.

No such associations between yogurt intake and the development of adenomas were evident among the women.

This is an observational study, and as such, can't establish cause. Further research would be needed to confirm the findings and uncover the biology involved, emphasise the researchers.

But the large number of people studied and the regular updates on diet and lifestyle factors add heft to the findings, they suggest.

By way of a possible explanation for what they found, the researchers point out that Lactobacillus bulgaricus and Streptococcus thermophilus, two bacteria commonly found in live yogurt, may lower the number of cancer causing chemicals in the gut.

And the stronger link seen for adenomas growing in the colon may partly be due to the lower acidity (pH) in this part of the gut, making it a more hospitable environment for these bacteria, they add.

Alternatively, yogurt may have anti-inflammatory properties and may reduce the 'leakiness' of the gut as adenomas are associated with increased gut permeability, they suggest.

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Good physical fitness in middle age linked to lower chronic lung disease risk

Good heart and lung (cardiorespiratory) fitness in middle age is associated with a lower long term risk of chronic lung disease (COPD), suggests Danish research published online in the journal Thorax.

Physical activity that boosts fitness should be encouraged "to delay development, progression and death from COPD," conclude the researchers.

COPD, short for chronic obstructive pulmonary disease, is an umbrella term for respiratory conditions that narrow the airways, such as bronchitis and emphysema. Smoking is the main risk factor for COPD, which the World Health Organization ranks as the fourth most frequent cause of death worldwide.

Studies have suggested that a high level of physical activity and/or leisure time exercise is associated with a reduced risk of COPD, and that physical inactivity may speed up its progression.

To explore this further, the researchers tracked the respiratory health of 4,730 healthy middle-aged men from the Copenhagen Male Study, who were recruited from 14 large workplaces in Copenhagen between 1970 and 1971. Their average age was 49.

Those with a previous diagnosis of COPD, asthma, or with symptoms of chronic bronchitis were excluded. Participants were monitored for up to 46 years to January 2016.

All participants provided information on smoking, alcohol intake, physical activity levels, educational attainment, occupation, and medical history.

Height, weight, and resting blood pressure were measured, and cardiorespiratory fitness (CRF) was calculated as low, normal, or high, using a VO2 max test -- a measure of the body's ability to use oxygen during exercise. National registers were used to identify cases of COPD and death from COPD.

Compared with low CRF, the estimated risk of COPD diagnosis was 21% lower in men with normal CRF and 31% lower in men with high CRF.

Similarly, compared with low CRF, the estimated risk of death from COPD was 35% lower in men with normal CRF and 62% lower in men with high CRF.

High CRF in middle age was also associated with a delay to both diagnosis of, and death from, COPD by 1.5 to 2 years.

The results were largely unchanged after excluding those who were diagnosed with COPD or who died during the first 10 years of monitoring, suggesting that the findings withstand scrutiny, say the researchers.

This is an observational study, and as such, can't establish cause. And it's possible that participants with high levels of CRF were more resilient to underlying COPD, delaying time to diagnosis, say the researchers.

But their results are in line with those of previous studies and provide further insight into the association between cardiorespiratory fitness and the long-term risk of COPD over an exceptionally long monitoring period.

And while the processes that link CRF with the development and progression of COPD aren't clear, the researchers nevertheless speculate that inflammation, linked to physical inactivity, may have a key role.

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Three public health interventions could prevent 94 million premature deaths

Increasing severity of sleep-disordered breathing and sleep disruption are associated with epigenetic age acceleration, according to preliminary results of a new study.

Results show that each standard deviation increase in the apnea-hypopnea index, a measure of sleep-disordered breathing severity, was associated with the equivalent of 215 days of biological age acceleration. Similarly, each standard deviation increase in the arousal index, a measure of sleep disruption, was associated with the equivalent of 321 days of age acceleration.

"People's biological age might not be the same as their chronological age," said lead author Xiaoyu Li, Sc.D., a postdoctoral research fellow in the Division of Sleep and Circadian Disorders in the Department of Medicine at Brigham and Women's Hospital and the Department of Social and Behavioral Sciences at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. "Individuals whose biological age is higher than their chronological age exhibit age acceleration or fast aging. In our study, we found that more severe sleep-disordered breathing is associated with epigenetic age acceleration. Our data provide biological evidence supporting adverse physiological and health effects of untreated sleep-disordered breathing."

Sleep-disordered breathing, such as obstructive sleep apnea, is characterized by abnormalities of respiration during sleep. Episodes often result in reductions in blood oxygen saturation and are usually terminated by brief arousals from sleep. Nearly 30 million adults in the U.S. have obstructive sleep apnea. Common warning signs include snoring and excessive daytime sleepiness.

According to the authors, epigenetic age acceleration is a DNA methylation-based marker of fast biological aging, and it is associated with modifiable lifestyle factors. Although sleep-disordered breathing is associated with multiple age-related health disorders, its relationship with epigenetic aging has not been well studied.

The study involved 622 adults with a mean age of 69 years; 53.2% were women. Participants were measured for blood DNA methylation, and their sleep was evaluated at home by polysomnography. Age acceleration measures were calculated as residuals from the regression of each epigenetic age on chronological age. The association of each sleep-disordered breathing trait with age acceleration was estimated using linear regression, controlling for socio-demographics, health behaviors, body mass index, and study site.

Another surprising finding was that the associations were stronger in women than in men, suggesting that women may be particularly vulnerable to the adverse effects of sleep-disordered breathing.

"While women are often considered to be at lower risk for health outcomes related to sleep-disordered breathing, our findings suggest increased biological susceptibility," said Li.

The authors suggested that future work should study whether treatment reduces epigenetic age acceleration among people who have sleep-disordered breathing.

"Since sleep-disordered breathing is not only common and treatable, but often undiagnosed and under-treated, our data highlight the potential for sleep-disordered breathing treatment to improve age-related chronic conditions and longevity," said Li. "Because epigenetic changes are reversible, epigenetic age estimators may be useful for identifying and validating anti-aging interventions."

The research abstract was published recently in an online supplement of the journal Sleep and will be presented Wednesday, June 12, in San Antonio at SLEEP 2019, the 33rd annual meeting of the Associated Professional Sleep Societies LLC (APSS), which is a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.

The study was supported by funding from the National Heart, Lung, and Blood Institute of the National Institutes of Health.

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Undetected diabetes linked to heart attack and gum disease

People with undetected glucose disorders run a higher risk of both myocardial infarction and periodontitis, according to a study published in the journal Diabetes Care by researchers at Karolinska Institutet in Sweden. The results demonstrate the need of greater collaboration between dentistry and healthcare, say the researchers, and possibly of screening for diabetes at dental clinics.

Severe periodontitis is already known to be associated with a higher risk of myocardial infarction and lowered glucose tolerance, and diabetes to be more common in people who have suffered a heart attack.

The researchers behind these earlier findings have now studied whether undetected glucose disorders (dysglycaemia) -- that is, a reduced ability to metabolise sugar -- is linked to both these conditions: myocardial infarction and periodontitis. The results are published in the journal Diabetes Care.

The study was a collaboration between cardiologists and dentists at Karolinska Institutet and was based on data from a previous study called PAROKRANK. It included 805 myocardial infarction patients from 17 Swedish cardiology clinics and 805 controls, who were matched by age, sex and post code. The patients' periodontitic status was assessed with X-rays and dysglycaemic status with glucose load tests.

Participants with a diabetes diagnosis were excluded from the study, which left 712 patients and 731 controls with data on both periodontitic status and glucose status, the latter of which was divided into three categories: normal, reduced glucose tolerance, newly detected diabetes. Comparisons were made after adjusting for age, sex, smoking habits, education and civil status.

The study shows that previously undetected glucose disorders, which include diabetes and impaired glucose tolerance, were linked to myocardial infarction. It was roughly twice as common for myocardial infarction patients to have undetected dysglycaemia as for healthy controls, confirming the research group's earlier findings. Myocardial infarction affects approximately 30,000 people in Sweden annually.

Undetected diabetes was also found to be linked to severe periodontitis. When myocardial infarction patients and controls were analysed separately, the association was clearer in the patients than in the controls, which is possibly because many of the controls were very healthy and few had severe periodontitis and undetected diabetes.

"Our findings indicate that dysglycaemia is a key risk factor in both severe periodontitis and myocardial infarction and that the combination of severe periodontitis and undetected diabetes further increases the risk of myocardial infarction," says the study's lead author Anna Norhammar, cardiologist and Associate Professor at Karolinska Institutet's Department of Medicine in Solna.

The results substantiate previously known links between periodontitis and diabetes and show that such an association also exists in previously unknown diabetes.

According to the researchers, the findings should make diabetes specialists consider their patients' dental health and the need for closer collaboration with dentists.

"The PAROKRANK study is a good example of such collaboration," says the present study's senior author Lars Rydén, Professor at Karolinska Institutet's Department of Medicine in Solna and chair of the academically initiated PAROKRANK study.

"Our study shows that undetected glucose disorders are common in two major diseases -- myocardial infarction and periodontitis," says Dr Norhammar. "Many people visit the dentist regularly and maybe it's worth considering taking routine blood-sugar tests in patients with severe periodontitis to catch these patients."

One of the study's limitations is that despite the large number of participants, the number of patients and controls with severe periodontitis and undetected diabetes was low. The observed differences in the links between undetected diabetes and severe periodontitis in patients and controls can therefore be attributable either to the low number of patients or to genuine differences in correlation.

The study was financed with grants from AFA Insurance, the Swedish Heart and Lung Foundation, the Swedish Research Council and Region Stockholm (ALF funding).

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Smelling with your tongue

Identification of functional olfactory receptors in human taste cells opens doors to new approaches to modify food flavor

Scientists from the Monell Center report that functional olfactory receptors, the sensors that detect odors in the nose, are also present in human taste cells found on the tongue. The findings suggest that interactions between the senses of smell and taste, the primary components of food flavor, may begin on the tongue and not in the brain, as previously thought.

"Our research may help explain how odor molecules modulate taste perception," said study senior author Mehmet Hakan Ozdener, MD, PhD, MPH, a cell biologist at Monell. "This may lead to the development of odor-based taste modifiers that can help combat the excess salt, sugar, and fat intake associated with diet-related diseases such as obesity and diabetes."

While many people equate flavor with taste, the distinctive flavor of most foods and drinks comes more from smell than it does from taste. Taste, which detects sweet, salty, sour, bitter, and umami (savory) molecules on the tongue, evolved as a gatekeeper to evaluate the nutrient value and potential toxicity of what we put in our mouths. Smell provides detailed information about the quality of food flavor, for example, is that banana, licorice, or cherry? The brain combines input from taste, smell, and other senses to create the multi-modal sensation of flavor.

Until now, taste and smell were considered to be independent sensory systems that did not interact until their respective information reached the brain. Ozdener was prompted to challenge this belief when his 12-year-old son asked him if snakes extend their tongues so they can smell.

In the study, published online ahead of print in Chemical Senses, Ozdener and colleagues used methods developed at Monell to maintain living human taste cells in culture. Using genetic and biochemical methods to probe the taste cell cultures, the researchers found that the human taste cells contain many key molecules known to be present in olfactory receptors.

They next used a method known as calcium imaging to show that the cultured taste cells respond to odor molecules in a manner similar to olfactory receptor cells.

Together, the findings provide the first demonstration of functional olfactory receptors in human taste cells, suggesting that olfactory receptors may play a role in the taste system by interacting with taste receptor cells on the tongue. Supporting this possibility, other experiments by the Monell scientists demonstrated that a single taste cell can contain both taste and olfactory receptors.

"The presence of olfactory receptors and taste receptors in the same cell will provide us with exciting opportunities to study interactions between odor and taste stimuli on the tongue," said Ozdener.

In addition to providing insight into the nature and mechanisms of smell and taste interactions, the findings also may provide a tool to increase understanding of how the olfactory system detects odors. Scientists still do not know what molecules activate the vast majority of the 400 different types of functional human olfactory receptors. Because the cultured taste cells respond to odors, they potentially could be used as screening assays to help identify which molecules bind to specific human olfactory receptors.

Moving forward, the scientists will seek to determine whether olfactory receptors are preferentially located on a specific taste cell type, for example, sweet- or salt-detecting cells. Other studies will explore how odor molecules modify taste cell responses and, ultimately, human taste perception.

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Mosquito scent discovery could change a billion lives

US researchers genetically modify mosquitoes making females less likely to spread diseases like dengue and Zika fever.

Researchers in the United States have genetically modified mosquitoes to make humans less attractive to them - a discovery that could dramatically reduce the spread of mosquito-borne diseases, such as dengue, malaria and Zika fever.

Female mosquitoes have been long known to use an array of sensory information to find people to bite. They can sense exhaled carbon dioxide from as far as 10 metres away, as well as being able to detect body odour, heat and moisture.

But new research, published in the journal Current Biology, has shown an acidic component in human sweat plays a key role in attracting the insect.

"We wanted to understand the genetic basis of how the mosquitoes detect their human hosts," Matthew DeGennaro, a mosquito neurobiology researcher at Florida International University, told Al Jazeera.

Gene identified

The scientists identified a gene - known as Ir8a - expressed in the mosquito's antenna. This gene appears to allow female mosquitoes, the ones that suck blood, to smell lactic acid, a particular acidic vapour in human sweat.

Using advanced CRISPR/Cas9 gene-editing technology, the researchers were able to disrupt that gene, making the female Aedes aegypti mosquitoes significantly less interested in humans.

"Removing the function of Ir8a removes approximately 50 percent of host-seeking activity," said DeGennaro.

The genetically-modified mosquitoes were less likely to detect and bite humans, making them much less likely to spread mosquito-borne illnesses.

For a species such as Aedes aegypti, which lives alongside half of the world's population and spreads diseases that kill millions of people each year, this genetic modification has huge potential health benefits.

"The transmission of diseases like dengue, yellow fever, Zika, and malaria can be blocked if we stop these mosquitoes from biting us," said DeGennaro

Repellent potential

While the release of genetically-modified mosquitoes into the wild to combat the spread of dengue fever has been a controversial practice, this latest research is not only focused on the potential of cross-breeding them with wild populations.

The researchers say their work can also offer a more advanced understanding of how mosquitoes hunt and feed on their human targets and will allow them to develop improved mosquito repellents.

These could include life-saving perfumes or scents that would disrupt mosquitoes' sense of smell and protect people from being bitten.

"Odours that mask the IR8a pathway could enhance the efficacy of current repellents like DEET or picaridin. In this way, our discovery may help make people disappear as potential hosts for mosquitoes," said DeGennaro.

In the same way, the researchers say they may be able to use the discovery to overstimulate parts of the insect's detection system and use the scent to lure them away from our humans and into traps.

The effect is "like getting on an elevator with someone who has put on way too much cologne", Larry Zwiebel, a biologist at Vanderbilt University, told US broadcaster NPR.

In February this year, the World Health Organization warned that an emerging resistance to insecticides could lead to a large increase in malaria cases and mortality.

The effects of climate change, which will make more parts of the world hospitable to mosquitoes and the diseases they spread, are also expected to hamper control efforts.

It's in this context that new and innovative insect control methods like those developed by the Florida researchers are going to become increasingly important.

Researchers were able to disrupt the Ir8a gene, making female mosquitoes significantly less interested in humans [Florida International University/Flickr]

Eating small amounts of red and processed meats may increase risk of early death

A new study out of Loma Linda University Health suggests that eating red and processed meats -- even in small amounts -- may increase the risk of death from all causes, especially cardiovascular disease.

Saeed Mastour Alshahrani, lead author of the study and a doctoral student at Loma Linda University School of Public Health, said the research fills an important gap left by previous studies that looked at relatively higher levels of red meat intake and compared them with low intakes.

"A question about the effect of lower levels of intakes compared to no-meat eating remained unanswered," Alshahrani said. "We wanted to take a closer look at the association of low intakes of red and processed meat with all-cause, cardiovascular diseases, and cancer mortality compared to those who didn't eat meat at all."

This study, "Red and Processed Meat and Mortality in a Low Meat Intake Population" is part of the Adventist Health Study-2 (AHS-2), a prospective cohort study of approximately 96,000 Seventh-day Adventist men and women in the United States and Canada. The principal investigator of AHS-2 is Gary E. Fraser, MD, PhD, professor of medicine and epidemiology at Loma Linda University Health.

Adventists are a unique population -- approximately 50 percent are vegetarians, and those who consume meat do so at low levels. This allowed researchers to investigate the effect of low levels of red and processed meat intake compared to zero-intake in a large setting such as the Adventist Health Study.

The study evaluated the deaths of over 7,900 individuals over an 11-year period. Diet was assessed by a validated quantitative food frequency questionnaire and mortality outcome data were obtained from the National Death Index. Of those individuals who consumed meat, 90 percent of them only ate about two ounces or less of red meat per day.

Nearly 2,600 of the reported deaths were due to cardiovascular disease, and over 1,800 were cancer deaths. Processed meat -- modified to improve flavor through curing, smoking, or salting (such as ham and salami) -- alone was not significantly associated with risk of mortality possibly due to a very small proportion of the population who consume such meat. However, the total intake of red and processed meat was associated with relatively higher risks of total and cardiovascular disease deaths.

Michael Orlich, MD, PhD, co-director of AHS-2 and co-author of the present study, said these new findings support a significant body of research that affirms the potential ill health effects of red and processed meats.

"Our findings give additional weight to the evidence already suggesting that eating red and processed meat may negatively impact health and lifespan," Orlich said.

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Aspirin to fight an expensive global killer infection

Research led by the Centenary Institute in Sydney has found a brand new target for treating drug-resistant tuberculosis; our scientists have uncovered that the tuberculosis bacterium hijacks platelets from the body's blood clotting system to weaken our immune systems.

Tuberculosis is far from eradicated around the world and still infects more than 1,400 people per year in Australia. Antibiotic resistant tuberculosis is particularly deadly and expensive to treat, costing up to $250,000 to treat a single case in Australia. Scientists at the Centenary Institute have been working on new ways to treat tuberculosis by increasing the effectiveness of the immune system.

Using the zebrafish model of tuberculosis, the researchers used fluorescent microscopy to observe the build-up of clots and activation of platelets around sites of infection. Senior author and head of the Centenary's Immune-Vascular Interactions laboratory, Dr Stefan Oehlers, says "the zebrafish gives us literal insight into disease processes by watching cells interacting in real time."

Following their hunch that these platelets were being tricked by the infection into getting in the way of the body's immune system, the researchers treated infections with anti-platelet drugs, including widely available aspirin, and were able to prevent hijacking and allow the body to control infection better.

Dr Elinor Hortle, lead author of the paper published in The Journal of Infectious Diseases, and Research Officer in Centenary's Immune-Vascular Interactions laboratory says "This is the first time that platelets have been found to worsen tuberculosis in an animal model. It opens up the possibility that anti-platelet drugs could be used to help the immune system fight off drug resistant TB."

There are over 1.2 million Australians living with latent tuberculosis, a non-infectious form of TB that puts them at risk of developing the active disease. "Our study provides more crucial evidence that widely available aspirin could be used to treat patients with severe tuberculosis infection and save lives," says Dr Hortle.

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