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Knowledge Update

An hour-long nap may boost memory, thinking in elderly

New York, Jan 6 (IANS) An hour-long nap after lunch may help older adults to preserve their memories, improve their ability to think clearly as well as to make decisions, a study has found. Sleep plays a key role in helping older adults maintain their healthy mental function, necessary for people as they age, the researchers said. In the study, led by Junxin Li from the University of Pennsylvania, Philadelphia, the team examined nearly 3,000 Chinese adults aged 65 and older to learn whether taking an afternoon nap had any effect on their mental health. The researchers found that nearly 60 per cent of the people took an afternoon nap after lunch. Their nap time was between about 30 minutes to more than 90 minutes, with most people taking naps lasting about 63 minutes. The results showed that people who took an hour-long nap after lunch had better health condition compared to people who did not take a nap -- neither shorter nor longer. Conversely, those who took no naps at all had four-to-six times more decrease in their mental ability. In addition, people who did not take a nap at all, and those who took shorter or longer naps, experienced about the same decline in their mental abilities that a five-year increase in age would be expected to cause, Li stated. The study was published in the Journal of the American Geriatrics Society.

Nearly 76 per cent people are 'overfat' globally: Study

​Sydney, Jan 5 (IANS) With nearly 76 per cent of the world's population becoming 'overfat', it has become the new pandemic that has quietly overtaken the world, a study has showed. 'Overfat' has been defined as a condition of having sufficient excess body fat to impair health. "This is a global concern because of its strong association with rising chronic disease and climbing healthcare costs, affecting people of all ages and incomes," said lead author Philip Maffetone, CEO of MAFF Fitness in Australia. In addition to those who are overweight and obese, others falling into the overfat category include normal-weight people, the researchers said. "The overfat category includes normal-weight people with increased risk factors for chronic disease, such as high abdominal fat and those with characteristics of a condition called normal-weight metabolic obesity," Maffetone added. "The overfat pandemic has not spared those who exercise or even compete in sports," he said. While the obesity epidemic has grown considerably over the last three to four decades, the study casts light on the much higher numbers of people who may have unhealthy levels of body fat. It also indicates that 9-10 per cent of the world population may be underfat. "While we think of the condition of underfat as being due to starvation, those worldwide numbers are dropping rapidly. However, an ageing population, an increase in chronic disease and a rising number of excessive exercisers or those with anorexia athletica, are adding to the number of non-starving underfat individuals," Maffetone explained. This leaves as little as 14 per cent of the world's population with normal body-fat percentage, showed the study, published in the journal Frontiers in Public Health.

Little extra zinc in diet may reduce DNA damage

​New York, Jan 3 (IANS) A modest increase in dietary zinc - about four milligrams - can help reduce everyday wear and tear on our DNA, says a study. While most DNA damage is harmless, some can have serious ramifications and a decrease in the body's ability to fix this wear and tear may be an important component of ageing. "We were pleasantly surprised to see that just a small increase in dietary zinc can have such a significant impact on how metabolism is carried out throughout the body," said lead researcher Janet King, Senior Scientist at Children's Hospital Oakland Research Institute in California. "These results present a new strategy for measuring the impact of zinc on health and reinforce the evidence that food-based interventions can improve micronutrient deficiencies worldwide," King noted. Zinc is ubiquitous in our body and facilitates many functions that are essential for preserving life. It plays a vital role in maintaining optimal childhood growth, and in ensuring a healthy immune system. Zinc also helps limit inflammation and oxidative stress in our body, which are associated with the onset of chronic cardiovascular diseases and cancers. Around much of the world, many households eat polished white rice or highly refined wheat or maize flours, which provide energy but do not provide enough essential micronutrients such as zinc. In the absence of sufficient zinc, our ability to repair everyday wear and tear on our DNA is compromised. In the six-week study, the scientists measured the impact of zinc on human metabolism by counting DNA strand breaks. They used the parameter of DNA damage to examine the influence of a moderate amount of zinc on healthy living. The findings -- published in the American Journal of Clinical Nutrition -- showed that a modest increase in dietary zinc reduces oxidative stress and damage to DNA.

Why obese individuals lack motivation to exercise?

New York, Jan 2 (IANS) Feeling too lazy to hit the gym or follow an exercise routine? Your altered dopamine receptors -- critical for movement -- may be the reason behind your lack of motivation rather than excess body weight, a new study has suggested. The study challenged a common belief that obese animals do less physical activity, because carrying extra body weight is physically disabling. "We know that physical activity is linked to overall good health, but not much is known about why people or animals with obesity are less active," said Alexxai V. Kravitz from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)- a part of the National Institutes of Health in the US. For the study, mice were fed either a standard or a high-fat diet for 18 weeks. Beginning in the second week, the mice on the unhealthy diet had higher body weight. By the fourth week, these mice spent less time moving and got around much more slowly when they did move. The results showed that the high-fat diet mice slowed down their activity, but they did it before they actually got fat instead of after, suggesting that the excess weight alone was not responsible for the reduced movements. The reason the mice were inactive was due to dysfunction in their dopamine systems. They had deficits in the D2 dopamine receptors, the researchers said. "There are probably other factors involved as well, but the deficit in D2 is sufficient to explain the lack of activity," said Danielle Friend, postdoctoral student at NIDDK. The study appeared in the journal Cell Metabolism.

Extra weight gain affects your DNA

​London, Dec 23 (IANS) The extra kilos you gain during the holidays would not only show up on your hips but could also affect your DNA, leading to changes in the expression of inflammatory genes, results of a large-scale international study suggest. The scientists examined the blood samples of over 10,000 women and men from Europe, a large proportion of whom were inhabitants of London of Indian ancestry, who according to the authors are at high risk for obesity and metabolic diseases. The study, published in the journal Nature, showed that a high BMI (body mass index) leads to epigenetic changes at nearly 200 loci of the genome -- with effects on gene expression. "In particular, significant changes were found in the expression of genes responsible for lipid metabolism and substrate transport, but inflammation-related gene loci were also affected," said group leader Harald Grallert from Helmholtz Zentrum Munchen - German Research Centre for Environmental Health, Neuherberg, Germany. While our genes do not change in the course of life, our lifestyle can directly influence their surroundings. Scientists spoke here of the epigenome, which refers to everything that happens on or around the genes. Up to now there has not been much research on how the epigenome is altered as a result of being overweight. "This issue is particularly relevant because an estimated one and a half billion people throughout the world are overweight," first author Simone Wahl of the Research Unit Molecular Epidemiology (AME) at Helmholtz Zentrum Munchen, noted. From the data, the team was also able to identify epigenetic markers that could predict the risk of Type-2 diabetes. "Our results allow new insights into which signaling pathways are influenced by obesity", said Christian Gieger, head of the AME. "We hope that this will lead to new strategies for predicting and possibly preventing Type-2 diabetes and other consequences of being overweight," Gieger said.

Follow some morning rituals for healthy day

​New Delhi, Dec 20 (IANS) Beginning your day on the right note is extremely important and hence it is necessary to follow some basic rituals like looking sharp and sweating it out for that confidence. Experts at Gillette dole out tips on how one can control their day by following five morning rituals. * Sweat it out: Nothing like a morning workout to boost your metabolism and stay energetic for the rest of the day. A walk, a run, a tennis match, a swim, pick one that works well with your body clock and fitness levels. * Eat right: A power breakfast can put you in the right mood to tackle the day's biggest tasks. * Look sharp: Start your day with a close, precise shave and a sharp dress code. How you look makes a world of difference to your confidence. Look, feel and perform your best every day. * Say no to distractions: Invest your time on social media instead of spending it. Say yes to everything that improves the quality of your work and say no to social media notifications that distract you from your productive morning routine. * Plan ahead: Experts believe in ‘power hour', an hour dedicated to planning your day and tackling the biggest and most difficult task.

Why morning people should not work at night

​London, Dec 18 (IANS) If you are a morning person, working in night shifts may affect you more, a study said. According to the study, morning persons demonstrate a quicker reaction time when solving unusual attention-related tasks when working at night, but are more prone to make errors. This may be the result of sleep deprivation and a relative increase in the time spent awake which negatively impacts the brain's attention system, the researchers said. The study showed that morning persons completed their tasks quicker than the night persons, but with errors. On the contrary, night persons were found to spend more time finishing than tasks. But, their level of accuracy in completing the task was higher, the researcher noted. "To deal with the most difficult test -- resolving a conflict of attention -- it was necessary not only to concentrate on the main visual stimulus, but at the same time to ignore accompanying stimulus that distract from the core task," said Andriy Myachykov from Oxford University. Though night people turned out to be slower, they were more efficient compared to the early risers. "Our study demonstrated how night owls working late at night 'sacrifice' speed for accuracy," Myachykov added. The results of this study may be useful for people who work night shift and could challenge the education system and human resources management in certain areas. For pilots, air traffic controllers, drivers, etc., attention, the ability to deal with large sets of data, and reaction time are all very important. During emergencies, these features could play a vital role. The study is available in the journal Experimental Brain Research.

Daily sauna bathing may reduce risk of dementia

London, Dec 17 (IANS) The sense of well-being and relaxation experienced during sauna bathing can help reduce risk of dementia, new research suggests. In a 20-year follow-up study involving 2,000 middle-aged men, the researchers found that men taking a sauna four to seven times a week were 66 per cent less likely to be diagnosed with dementia than those taking a sauna once a week. The more frequently saunas were taken, the lower was the risk of dementia, showed the study published in the journal Age and Ageing. Frequent sauna bathing was earlier found to significantly reduce the risk of sudden cardiac death, the risk of death due to coronary artery disease and other cardiac events, as well as overall mortality. Sauna bathing may protect both the heart and memory to some extent via similar, still poorly known mechanisms, said lead researcher Jari Laukkanen, Professor at University of Eastern Finland. "However, it is known that cardiovascular health affects the brain as well. The sense of well-being and relaxation experienced during sauna bathing may also play a role," Laukkanen noted. The effects of sauna bathing on the risk of Alzheimer's disease and other forms of dementia were studied in the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD), involving more than 2,000 middle-aged men living in the eastern part of Finland. Based on their sauna-bathing habits, the study participants were divided into three groups -- those taking a sauna once a week, those taking a sauna two to three times a week, and those taking a sauna four to seven times a week. Among those taking a sauna four to seven times a week, the risk of any form of dementia was 66 per cent lower and the risk of Alzheimer's disease 65 per cent lower than among those taking a sauna just once a week, the study said.

Make running your New Year's resolution to stay sharp

​New York, Dec 15 (IANS) If you are running out of ideas for your New Year's resolution, consider running. Researchers have found that runners show greater functional connectivity in brain regions important for tasks such as planning and decision-making. "These activities (such as running) that people consider repetitive actually involve many complex cognitive functions -- like planning and decision-making -- that may have effects on the brain," said one of the researchers David Raichlen, Associate Professor at University of Arizona, at Tucson in the United States. For the study, the researchers compared brain scans of young adults engaged in cross-country running to young adults who do not engage in regular physical activity. Participants were roughly the same age -- 18 to 25 -- with comparable body mass index and educational levels. The runners, overall, showed greater functional connectivity -- or connections between distinct brain regions -- within several areas of the brain, including the frontal cortex, which is important for cognitive functions such as planning, decision-making and the ability to switch attention between tasks. The findings, published in the journal Frontiers in Human Neuroscience, suggest that running may affect the structure and function of the brain in ways similar to complex tasks like playing a musical instrument. Since functional connectivity often appears to be altered in ageing adults, and particularly in those with Alzheimer's or other neurodegenerative diseases, it is an important measure to consider, Gene Alexander, Professor at University of Arizona, noted.

Low-carb diets effective for weight loss

​New York, Dec 14 (IANS) Researchers have found that eating food low in carbohydrates is safe for up to six months and can also help reduce more weight than following a low-fat diet. "Adhering to a short-term low-carb diet appears to be safe and may be associated with weight reduction," said lead researcher Heather Fields, MD, an internal medicine physician at Mayo Clinic in Arizona, US. "We encourage patient to eat real food and avoid highly processed foods, especially processed meats, such as bacon, sausage, deli meats, hot dogs, and ham when following any particular diet," Fields noted. Depending on the diet, participants lost between two-and-a-half to almost nine more pounds than those who followed a low-fat diet, showed the findings published in the Journal of the American Osteopathic Association. Analysing research published over more than a decade, Fields reviewed articles that addressed potential adverse effects and overall safety of low-carb diets. Diets that heavily restrict carbohydrates often lead to greater consumption of meats -- some of which have been implicated in worsened all-cause mortality and increased cancer risk. While available studies did not consistently address the source or quality of proteins and fats consumed in such diets, they did show short-term efficacy in weight loss without negative effects on blood pressure, glucose, and cholesterol, compared with other diets.