Knowledge Update

​London, Feb 23 (IANS) People who suffer long-term stress may also be more prone to gaining extra kilos overtime, says a study. The findings, published in the journal Obesity, are based on examination of hair samples for levels of cortisol, a hormone which regulates the body's response to stress. The study showed that exposure to higher levels of cortisol over several months is associated with people being more heavily, and more persistently, overweight. "People who had higher hair cortisol levels also tended to have larger waist measurements, which is important because carrying excess fat around the abdomen is a risk factor for heart disease, diabetes, and premature death," said lead researcher Sarah Jackson from the University College London. "These results provide consistent evidence that chronic stress is associated with higher levels of obesity," Jackson added. Chronic stress has long been hypothesised to be implicated in obesity -- people tend to report overeating and 'comfort eating' foods high in fat, sugar and calories in times of stress, and the stress hormone cortisol plays an important role in metabolism and determining where fat is stored. Previous studies looking at the link between cortisol and obesity relied mainly on measurements of the hormone in blood, saliva or urine which may vary according to the time of day and other situational factors. These studies failed to capture long-term cortisol levels. This research involved 2,527 men and women aged 54 and older taking part in the English Longitudinal Study of Ageing, taking data over a four-year period. In the research, the scientists took a lock of hair two centimetre long from each participant which was cut as close possible to a person's scalp. This represented approximately two months' hair growth with associated accumulated levels of cortisol. The researchers found that people who had higher levels of cortisol present in their hair tended to have larger waist circumference measurements, were heavier, and had a higher body mass index (BMI).

​London, Feb 23 (IANS) Intake of 10 portions or 800 grammes of fruit and vegetables a day may potentially prevent approximately 7.8 million premature deaths worldwide every year, say researchers. The results, published in the journal International Journal of Epidemiology, revealed that eating up to 800g fruit and vegetables a day - or 10 portions - was associated with a 24 per cent reduced risk of heart disease, a 33 per cent reduced risk of stroke, a 28 per cent reduced risk of cardiovascular disease, a 13 per cent reduced risk of total cancer, and a 31 per cent reduction in dying prematurely. "We wanted to investigate how much fruit and vegetables you need to eat to gain the maximum protection against disease, and premature death. Our results suggest that although five portions of fruit and vegetables is good, ten a day is even better," said lead author Dagfinn Aune from Imperial College, London. The researchers found that apples and pears, citrus fruits, salads and green leafy vegetables such as spinach, lettuce and chicory, and cruciferous vegetables such as broccoli, cabbage and cauliflower, may reduce the risk of specific diseases. "Fruit and vegetables have been shown to reduce cholesterol levels, blood pressure and to boost the health of our blood vessels and immune system. This may be due to the complex network of nutrients they hold. For instance they contain many antioxidants, which may reduce DNA damage and lead to a reduction in cancer risk," Aune added. For the study, the team conducted a meta-analysis of all available research in populations worldwide, included up to 2 million people, and assessed up to 43,000 cases of heart disease, 47,000 cases of stroke, 81,000 cases of cardiovascular disease, 112,000 cancer cases and 94,000 deaths.

​New York, Feb 20 (IANS) Chronic exposure to a common food additive found in everything from chewing gum to bread can decrease the ability of small intestine cells to absorb nutrients and act as a barrier to pathogens, warns a study. Ingestion of the compound, known as titanium dioxide, is nearly unavoidable. It can enter the digestive system through toothpastes, as titanium dioxide is used to create abrasion needed for cleaning. The oxide is also used in some chocolates to give it a smooth texture. "Titanium oxide is a common food additive and people have been eating a lot of it for a long time -- don't worry, it won't kill you! -- but we were interested in some of the subtle effects, and we think people should know about them," said one of the authors of the study, Gretchen Mahler, Assistant Professor at Binghamton University, State University of New York. For the study, the researchers exposed a small intestinal cell culture model to the physiological equivalent of a meal's worth of titanium oxide nanoparticles -- 30 nanometers across -- over four hours (acute exposure), or three meal's worth over five days. Acute exposures did not have much effect, but chronic exposure diminished the absorptive projections on the surface of intestinal cells called microvilli, showed the findings published in the journal NanoImpact. With fewer microvilli, the intestinal barrier was weakened, metabolism slowed and some nutrients -- iron, zinc, and fatty acids, specifically -- were more difficult to absorb. Enzyme functions were negatively affected, while inflammation signals increased, the study said. "To avoid foods rich in titanium oxide nanoparticles you should avoid processed foods, and especially candy. That is where you see a lot of nanoparticles," Mahler said.

​Children who regularly intake fructose present in soda, sweetened beverages, pizza and salty food, biscuits, yogurt may be be prone to liver disease, researchers warn. According to a study, led by researchers from Bambino Gesu Hospital in Italy, dietary fructose increases serum uric acid concentrations.

Both uric acid concentration and fructose consumption may be high in individuals with non-alcoholic fatty liver disease (NAFLD) -- a condition where extra fat is accumulated in liver cells in people who drink little or no alcohol. It is estimated to affect up to 30 per cent of the general population in Western countries and up to 9.6 per cent of all children and 38 per cent of obese children across a spectrum of liver disease, including NASH (defined as steatosis, hepatocyte ballooning and inflammation).

Although NASH is a less aggressive form of NAFLD, it can progress to severe fibrosis and cirrhosis, with development of hepatocellular carcinoma in adults. The findings suggested that fructose consumption was independently associated with high uric acid, which occurred more frequently in patients with NASH than in not-NASH patients.

"It is plausible that dietary fructose intake and uric acid concentrations are potential risk factors for liver disease progression in NAFLD," said Valerio Nobili from Bambino Gesu Hospital in Italy.

"The study shows for the first time that uric acid concentrations and dietary fructose consumption are independently and positively associated with NASH," Nobili added. For the study, reported in the Journal of Hepatology, the team analysed 271 obese children and adolescents with NAFLD -- 155 males, mean age 12.5 years -- who underwent liver biopsy.

Nearly 90 per cent were found drinking sodas and soft drinks one or more times a week. Almost 95 per cent of patients regularly consumed morning and afternoon snacks consisting of crackers, pizza and salty food, biscuits, yogurt, or other snacks. The development of NASH may markedly affect life expectancy and quality of life in affected individuals.

Thus, "it is crucial to understand the risk factors for NASH in children and adolescents in order to design effective interventions," Nobili said.

​London, Feb 15 (IANS)

New York, Feb 14 (IANS) While anti-ageing moisturisers only go skin deep, reducing calorie consumption can slow the ageing process at cellular level, suggests new research. The study, published in the journal Molecular & Cellular Proteomics, showed that when ribosomes -- the cell's protein makers -- slow down, the ageing process slows too. The decreased speed lowers production but gives ribosomes extra time to repair themselves. "The ribosome is a very complex machine, sort of like your car, and it periodically needs maintenance to replace the parts that wear out the fastest," said study senior author John Price, Professor at Brigham Young University in in Provo, Utah, US. So what causes ribosome production to slow down in the first place? Reduced calorie consumption, show the results of the study tested in mice. Price and his fellow researchers observed two groups of mice. One group had unlimited access to food while the other was restricted to consume 35 per cent fewer calories, though still receiving all the necessary nutrients for survival. "When you restrict calorie consumption, there's almost a linear increase in lifespan," Price said. "We inferred that the restriction caused real biochemical changes that slowed down the rate of ageing," he added. "The calorie-restricted mice are more energetic and suffered fewer diseases," Price said. "And it's not just that they're living longer, but because they're better at maintaining their bodies, they're younger for longer as well," he said. Despite this study's observed connection between consuming fewer calories and improved lifespan, Price assured that people should not start counting calories and expect to stay forever young. Calorie restriction has not been tested in humans as an anti-ageing strategy, the researchers pointed out.

New York, Feb 13 (IANS) Losing weight through surgical approaches appears to reset chemical messages that fat cells send, substantially reducing people's risk of developing Type 2 diabetes, a study has found. Fat cells -- also known as adipocytes -- send messages to other cells in the form of exosomes -- nanosised blobs whose contents regulate which proteins are produced by genes. However, the messages contained in exosomes from patients who are obese alter how the body processes insulin, setting the stage for Type 2 diabetes, said researchers from the George Washington University School of Medicine and Health Sciences. For the study, published in the journal Obesity, the team worked with six adults scheduled to receive gastric bypass surgery, whose average age was 38 years, and had an average body mass index (BMI) of 51.2 kg/m2. Blood samples showed that at least 168 microRNAs -- the molecules responsible for sending specific messages -- had changed before and after surgery. Further analyses showed that many of these microRNAs were involved in insulin signalling, the pathways that the body uses to regulate blood sugar. By changing these outgoing microRNAs for the better, adipocytes actively were encouraging higher insulin sensitivity in other cells, warding off Type 2 diabetes, said Robert J. Freishtat, Associate Professor at the George Washington University School of Medicine and Health Sciences. Post-surgery each volunteer showed better insulin sensitivity and other improved markers of metabolic health. "These volunteers were essentially cured of their diabetes after surgery. The changes we saw in their surgery-responsive microRNAS correlated with the changes we saw in their metabolic health," Freishtat said. The findings offer hope to the nearly 2 billion adults who are overweight or obese worldwide that many of the detrimental effects of carrying too much weight can recede, even on the molecular level, once they lose weight, the researchers noted.

​London, Feb 12 (IANS) Although taking selfies is hugely popular, most people would prefer to see fewer selfies on social media, a study has found. Selfies are enormously popular on social media. According to Google statistics estimates, about 93 million selfies were taken per day in 2014, counting only those taken on Android devices. The findings showed that compared to the selfies taken by themselves, people attributed greater self-presentational motives and less authenticity to selfies taken by others. Selfies taken by themselves were also judged as self-ironic and more authentic. This phenomenon, where many people regularly take selfies but most people don't appear to like them has been termed the "selfie paradox" by Sarah Diefenbach, Professor at Ludwig-Maximilians-University in Germany. To assess people's motives and judgements when taking and viewing selfies, the team conducted an online survey of a total of 238 persons living in Austria, Germany and Switzerland. The results showed that 77 per cent of the participants regularly took selfies. "One reason for this might be their fit with widespread self-presentation strategies such as self-promotion and self-disclosure" Diefenbach said, in the paper published in the journal Frontiers in Psychology. Interestingly, despite 77 per cent of the participants taking selfies regularly, 62-67 per cent agreed on the potential negative consequences of selfies, such as impacts on self-esteem. This negative perception of selfies was also illustrated by 82 per cent of participants indicating that they would rather see other types of photos instead of selfies on social media.

New York, Feb 11 (IANS) Finding it tough to cope with stress in your life? Eat prebiotics fibers that may help protect the beneficial bacteria in your gut and restore healthy sleep patterns after a stressful event, researchers suggest. Prebiotics are certain types of non-digestible fibers that probiotic bacteria feed on, such as the fibers found in many plant sources like asparagus, oatmeal, and legumes as well as in breast milk. The findings showed that stress could upset the gut's microbiome, as well as restful sleep -- essential elements for a healthy life. "Acute stress can disrupt the gut microbiome," said Agnieszka Mika, postdoctoral fellow at the University of Colorado Boulder, in the US. A diet rich in prebiotics was found to increase beneficial bacteria as well as protect gut microbes from stress-induced disruptions. In addition, prebiotics also lead to the recovery of normal sleep patterns, since they tend to be disrupted after stressful events. "So far no adverse effects from prebiotics have been reported...and they are found widely in many plants, even present in breast milk, and are already commercially available," Mika added. For the study, published in the journal Frontiers in Behavioral Neuroscience, the team tested rats that received prebiotic diets for several weeks prior to a stressful test condition and compared with control rats that did not receive the prebiotic-enriched diet. The rats that ate prebiotics prior to the stressful event did not experience stress-induced disruption in their gut microbiota and also recovered healthier sleep patterns sooner than controls, the researchers said. As the stressor that the rats received was the equivalent of a single intense acute stressful episode for humans, such as a car accident or the death of a loved one, the results may be relevant in humans, noted Robert S. Thompson from the University of Colorado Boulder.

London, Feb 8 (IANS) Using Facebook can be a fun way to while away the hours -- but a new study suggests that updating your status or commenting on a friend's holiday pictures can make us lose track of time as we do it. People who are using Facebook or surfing the web suffer impaired perception of time, said the study published in the Journal of Applied Social Psychology. "We found evidence that Internet and Facebook related stimuli can distort time perception due to attention and arousal related mechanisms," said the study by researchers from University of Kent in England. The researchers found that the way people perceived time varied according to whether their internet use was specifically Facebook related or more general. Using well-established internal clock models, the researchers attempted to separate the roles of 'attention' and 'arousal' as drivers for time distortion. In the study, Lazaros Gonidis and Dinkar Sharma monitored the responses of 44 people who were shown images for varying degrees of time. While some of the images were associated with Facebook, another set had more general internet associations with yet another set as neutral 'control' images. Those taking part had to say whether the image they had just seen had been visible for a short or long time. The key finding was that people tended to underestimate the time they had been looking at Facebook-related images to a greater extent than other more general internet related images, but that in both cases time was underestimated. This suggests that Facebook-related images affect time by changing how we pay attention to them. The researchers believe that the findings are likely to have implications for future study into addictive behaviour.

​New York, Feb 8 (IANS) Besides keeping you physically fit, a brisk walk or a long swim may be the key to preventing a bad day at the office from spilling over into the home, says a study. "Research shows employees who are mistreated at work are likely to engage in similar behaviours at home," said one of the researchers Shannon Taylor from University of Central Florida in the US. "If they've been belittled or insulted by a supervisor, they tend to vent their frustration on members of their household. Our study shows that happens because they're too tired to regulate their behaviour," Taylor noted. The findings, published in the Journal of Applied Psychology, showed that sleep and exercise are intervention points that can be leveraged to prevent the spread of harmful behaviour. Study participants included 118 MBA students with full-time jobs who took a survey and then wore activity monitors for a week. A follow-up survey was then sent to the participants' cohabitants. Tracking participants' sleep patterns and daytime physical movements, the researchers found that employees who recorded an average of more than 10,900 steps each day were less likely to perpetuate abuse at home than those recording fewer than 7,000. "The study gives us a new perspective on the importance of getting an adequate amount of sleep and exercise. It's not just good for you, it's good for your spouse, too," Taylor said.