20th Feb 2015, 03:55 PM #1771
Re: Health Bulletin
Lack of sleep can up risk of type 2 diabetes
Those who sleep less are at a higher risk of diabetes. Lack of sleep has been found to elevate levels of free fatty acids in the blood accompanied by temporary pre-diabetic conditions in healthy young men.
"We have found connections between restricted sleep, weight gain and type 2 diabetes," said Esra Tasali, assistant professor of medicine at the University of Chicago and senior author of the study. "Experimental laboratory studies, like ours help us unravel the mechanisms that may be responsible."
The study is the first to examine the impact of sleep loss on 24-hour fatty acid levels in the blood.
It adds to emerging evidence that insufficient sleep -- a highly prevalent condition in modern society -- may disrupt fat metabolism and reduce the ability of insulin to regulate blood sugars. It suggests that something as simple as getting enough sleep could help counteract the current epidemics of diabetes and obesity.
The researchers found that after three nights of getting only four hours of sleep, blood levels of fatty acids, which usually peak and then recede overnight, remained elevated from about 4 am to 9 am. As long as fatty acid levels remained high, the ability of insulin to regulate blood sugars was reduced.
The researchers recruited 19 healthy male subjects between the ages of 18 and 30. These volunteers were monitored through two scenarios in randomized order. In one they got a full night's rest -- 8.5 hours in bed (averaging 7.8 hours asleep) during four consecutive nights. In the other they spent just 4.5 hours in bed (averaging 4.3 hours asleep) for four consecutive nights. The two studies were spaced at least four weeks apart.
Each subject's sleep was carefully monitored, diet was strictly controlled and blood samples were collected at 15 or 30 minute intervals for 24 hours, starting on the evening of the third night of each study. They found that sleep restriction resulted in a 15 to 30% increase in late night and early morning fatty acid levels.
21st Feb 2015, 02:36 PM #1772
Re: Health Bulletin
Cholesterol no longer a concern: US experts
More butter, anyone? A warning against eating foods high in cholesterol is no longer included in the US government's draft dietary guidelines for Americans, representing a major shift in policy, officials said Thursday.
Until now, the Dietary Guidelines for Americans recommended that cholesterol intake be limited to 300 milligrams per day -- the amount in about one stick of butter, or two small eggs, or a 10-ounce (300 gram) steak.
Medical experts used to believe that eating too much cholesterol could raise the risk of heart attack and stroke by contributing to plaque buildup in the arteries.
But the 2015 version of the guidelines will no longer place an upper limit on cholesterol "because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol," the US Department of Agriculture said in a statement.
The draft report, published online at health.gov/dietaryguidelines, said "cholesterol is not a nutrient of concern for overconsumption."
The recommended changes were compiled by 14 nationally recognized nutrition, medicine and public health experts.
The guidelines do not become official right away. Instead, they are open for a 45-day comment period and will be discussed at a public meeting in Bethesda, Maryland on March 24.
"We have seen this controversy, especially surrounding the consumption of eggs, which are very high in cholesterol yet filled with beneficial nutrients," said Suzanne Steinbaum, preventive cardiologist at Lenox Hill Hospital in New York.
The committee "clearly is trying to dispel the idea that cholesterol matters."
While cholesterol may be getting a free pass, the saturated fat that usually accompanies it is not.
In fact, experts recommend that Americans eat less than before. Calories from saturated fat should make up about eight percent of a person's daily calorie intake, compared to the 2010 guidelines that advised 10 percent.
For an average person, eating 2,000 calories per day, the new guidelines would mean the limit of saturated fat could be achieved with a few spoonfuls of butter, or a dozen eggs -- since eggs are naturally low in saturated fat -- or a seven-ounce steak.
"Saturated fat is still a nutrient of concern for overconsumption, particularly for those older than the age of 50 years," said the report.
The recommended changes show "good progress in the arena of nutrition science," said Rebecca Solomon, director of clinical nutrition at Mount Sinai Beth Israel hospital in New York.
"We have known for many years that cholesterol levels are impacted primarily by genetics and high saturated fat intake and not by intake of dietary cholesterol. I am happy to see this evolved position."
The overarching theme of the draft guidelines was to urge Americans to eat more fruit and vegetables, and Mediterranean and vegetarian diets were recommended as healthy options.
"A diet higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts and seeds, and lower in calories and animal-based foods is more health-promoting and is associated with less environmental impact than is the current US diet," the report said.
Environmental groups applauded the draft's mention of sustainability, saying such changes could help reduce global warming and food insecurity.
"The inclusion of sustainability criteria in the Dietary Guidelines' recommendations is a huge step forward for human and planetary health," said Kari Hamerschlag, senior program manager at Friends of the Earth.
"By recommending consumption of more plant foods and less meat, these guidelines will encourage people to lessen the huge impact of our diets on our natural resources."
21st Feb 2015, 02:37 PM #1773
Re: Health Bulletin
Sunbathers take heed: Skin damage continues hours after exposure
Here's a warning to sunbathers everywhere. Scientists have found that the skin damage caused by UV rays does not stop once you get out of the sun.
Researchers said on Thursday much of the potentially cancer-causing damage wrought by ultraviolet radiation from sunlight or tanning beds occurs up to three to four hours after exposure thanks to chemical changes involving the pigment melanin.
But there is some good news. The researchers said it may be possible to develop sunscreen that protects against this type of damage. Melanoma, closely linked to UV exposure, accounts for most skin cancer deaths.
The role of melanin, responsible for our skin, eye and hair color, in promoting DNA damage was a surprise because melanin was previously known to play a protective role by absorbing much of the UV energy before it penetrates the skin.
"But the unusual chemical properties of melanin that make it a good UV absorber also make it susceptible to other chemical reactions that just happen to have the same end result as the UV," said Douglas Brash, a therapeutic radiology and dermatology professor at the Yale School of Medicine whose study appears in the journal Science.
The researchers revealed this aspect of melanin in experiments involving human cells in a lab dish as well as lab mice and mouse cells in a dish.
UV exposure can cause DNA damage that may spur carcinogenic mutations in melanin-producing cells called melanocytes.
The researchers exposed mouse and human melanocytes to radiation from a UV lamp. The cells experienced DNA damage immediately but the damage also continued for hours. In fact, half of the damage occurred in the hours after exposure.
After a type of chemical reaction called chemiexcitation, also witnessed in bioluminescent creatures including fire flies, energy gets transferred to DNA to potentially cause mutations.
"People should be aware of the chemistry initiated in the skin after the UV exposure so that they can take proper care of themselves whenever going out in the sun or to the beach," said Yale School of Medicine researcher Sanjay Premi.
"We'd like to find new ingredients for sunscreens that will block these reactions," Brash added. "But in the meantime, I tell people to enjoy the sun but just don't lie on the beach between 10 a.m. and 2 p.m., and wear a hat. Sunscreens are useful, too, so long as they block both UVB and UVA," two kinds of ultraviolet rays.
21st Feb 2015, 02:37 PM #1774
Re: Health Bulletin
Gene may help reduce GM contamination
Researchers, including those of Indian-origin, have identified a gene that may help reduce contamination of conventional crops by genetically modified (GM) crops.
The plant gene discovered by University of Guelph scientists might help farmers reduce the risk of GM contamination and quell arguments against the use of transgenic food crops, said Sherif Sherif, lead author of a new research paper describing the findings.
This is believed to be the first-ever study to identify a gene involved in altering fruit trees that normally cross-pollinate - needing one plant to fertilise another — into self-pollinators, said Sherif.
Sherif said researchers might one day insert this gene into GM crops to prevent their pollen from reaching other plants.
"There are a lot of transgenic crops worldwide," said plant agriculture professor Jay Subramanian, Sherif's PhD supervisor and a co-author on the paper.
"There is concern about pollen from them being able to fertilise something in the wild population, thus creating 'super weeds'." Subramanian said.
The researchers found a gene making a protein that naturally allows a small handful of plants to self-pollinate and make fruit before the flower opens.
Peaches, for example, have closed flowers, unlike their showy-flowered plum and cherry cousins that need pollen from another tree to fertilise and set fruit.
Other co-authors on the paper are Guelph professors Jaideep Mathur, Department of Molecular and Cellular Biology and Gopi Paliyath, from Department of Plant Agriculture, along with Islam El-Sharkawy, a former research associate with Subramanian; and colleagues at the National University of Singapore.
Besides aiding crop farmers and food producers, their discovery might be a boon to perfume-makers, said Subramanian.
Used in fragrant perennials such as jasmine, the gene might keep flowers closed and allow growers to collect more of the aromatic compounds prized by perfume-makers.
"That's when volatile compounds are peaking. When the flower opens, you lose almost 80 per cent of those volatiles," said Subramanian.
22nd Feb 2015, 03:11 PM #1775
Re: Health Bulletin
Diabetes, depression may increase dementia risk
Diabetes or psychiatric symptoms such as depression increases risk of dementia in people with mild cognitive impairment (MCI), a new research has found.
The findings suggest that lifestyle changes to improve diet and mood might help people with MCI to avoid dementia.
"There are strong links between mental and physical health, so keeping your body healthy can also help to keep your brain working properly," said lead author Claudia Cooper from University College London.
MCI is a state between normal ageing and dementia, where someone`s mind is functioning less well than would be expected for their age.
It affects 19 percent of people aged 65 and over, and around 46 percent of people with MCI develop dementia within three years compared with three percent of the general population
The researchers analysed data from 62 separate studies, following a total of 15,950 people diagnosed with MCI.
Among people with MCI, those with diabetes were 65 percent more likely to progress to dementia and those with psychiatric symptoms were more than twice as likely to develop the condition, the findings showed.
The study was published in the American Journal of Psychiatry.
23rd Feb 2015, 01:57 PM #1776
Re: Health Bulletin
Now, same-sex couples can make babies
In a breakthrough, researchers led by an Indian-origin scientist, have shown that stem cells from the skin of two adults of the same sex can be used to make human egg and sperm cells.
Scientists at Cambridge University collaborated with Israel's Weizmann Institute of Science and used stem cell lines from embryos as well as from the skin of five different adults. Researchers have previously created live baby mice using engineered eggs and sperm, but until now have struggled to create a human version of these 'primordial germ' or stem cells.
Ten different donor sources have been used so far and new germ-cell lines have been created from all of them, researchers said.
The team has compared the engineered germ cells with natural human stem cells taken from aborted human fetuses to check that the artificially created versions of the cells had identical characteristics, The Times reported. A gene called SOX17, previously considered to be unimportant in mice, has turned out to be critical in the process of 'reprogramming' human cells, researchers said.
"We have succeeded in the first and most important step of this process, which is to show we can make these very early human stem cells in a dish," said Azim Surani, professor of physiology and reproduction at Cambridge, who heads the project.
"We have also discovered that one of the things that happens in these germ cells is that epigenetic mutations, the cell mistakes that occur with age, are wiped out," said Surani, who was involved in research that led to the birth of Louise Brown, the world's first test-tube baby, in 1978.
Jacob Hanna, the specialist leading the project's Israeli arm, said it may be possible to use the technique to create a baby in just two years.
"It has already caused interest from gay groups because of the possibility of making egg and sperm cells from parents of the same sex," he said. The details of the technique were published in the journal Cell.
24th Feb 2015, 04:10 PM #1777
Re: Health Bulletin
Vitamin D deficiency causes diabetes, not obesity
A new study has examined that people who have low levels of vitamin D are more likely to have diabetes, regardless of how much they weigh.
The study conducted by the Endocrine Society found that people who have low levels of vitamin D are more likely to be obese and they also are more likely to have Type 2 diabetes, prediabetes and metabolic syndrome than people with normal vitamin D levels.
Vitamin D helps the body absorb calcium and maintain bone and muscle health. The skin naturally produces this vitamin after exposure to sunlight. People also absorb smaller amounts of the vitamin through foods, such as milk fortified with vitamin D. More than 1 billion people worldwide are estimated to have deficient levels of vitamin D due to limited sunshine exposure.
25th Feb 2015, 04:43 PM #1778
Re: Health Bulletin
'Early peanut intake could prevent allergy'
Turning what was once conventional wisdom on its head, a new study suggests that many, if not most peanut allergies, can be prevented by feeding young children food containing peanuts beginning in infancy, rather than avoiding such foods.
About 2% of American children are allergic to peanuts, a figure that has more than quadrupled since 1997 for reasons that are not entirely clear. There have also been big increases in other Western countries. For some people, even traces of peanuts can be life-threatening.
An editorial published on Monday in The New England Journal of Medicine, along with the study, called the results "so compelling" and the rise of peanut allergies "so alarming" that guidelines for how to feed infants at risk of peanut allergies should be revised soon.
The study "clearly indicates that the early introduction of peanut dramatically decreases the risk of development of peanut allergy," said the editorial, by Dr. Rebecca S Gruchalla of the University of Texas Southwestern Medical Center and Dr. Hugh A Sampson of the Icahn School of Medicine at Mount Sinai in New York City. It also "makes it clear that we can do something now to reverse the increasing prevalence of peanut allergy."
In the study, conducted in London, infants 4 to 11 months old who were deemed at high risk of developing a peanut allergy were randomly assigned either to be regularly fed food that contained peanuts or to be denied such food. These feeding patterns continued until the children were 5 years old. Those who consumed the foods that had peanuts in them were far less likely to be allergic to peanuts when they turned 5.
Dr. Gideon Lack, a professor of pediatric allergy at King's College London and the study leader, said the practice of withholding peanuts from babies "could have been in part responsible for the rise in peanut allergies". Whether infants should be fed peanuts and other foods associated with allergies is one of the most common questions parents ask about introducing solid foods to their children, said Dr. Ruchi Gupta, associate professor of pediatrics at Northwestern University, who was not involved in the study. "And until now most of what we can say is there's not very conclusive data."
The American Academy of Pediatrics, in guidelines released in 2000, recommended that peanuts be withheld from children at risk of developing allergies until they were 3 years old.
In 2008, the academy revised its stance, saying there was no conclusive evidence that avoidance of certain foods beyond 4 to 6 months of age helped stave off allergies, but stopped short of recommending that parents give their young children such foods.
"There was no study showing that that was the right thing to do," said Dr. Wesley Burks, chairman of pediatrics at the University of North Carolina, who was not involved in the new research. Now, with the new study, he said, there is such evidence.
The results of the study were presented on Monday at the annual meeting of the American Academy of Allergy, Asthma and Immunology in Houston.
Pediatricians caution that parents should not feed whole peanuts to infants because of the choking risk, but rather peanut butter or other foods.
Dr. Lack said he first began to question the conventional wisdom about 15 years ago when he gave a talk in Tel Aviv and asked doctors in the audience how many had patients with peanut allergy. Only three hands went up. "In the U.K., if you had asked that question, every single member of the audience would have put up their hand," he said.
So Dr. Lack and colleagues conducted a survey, published in 2008, that found the rate of peanut allergy in Israeli children was only about one-tenth that of Jewish children in Britain. The best explanation, they concluded, was that Israeli infants consumed high amount of peanut protein in the first year of life while parents in Britain avoided giving such foods.
Some other studies have also found that earlier feeding of allergy-inducing foods was associated with lower allergy rates. But such observational studies are not definitive because there could be unexplored factors that account for the differences.
The new study, by contrast, was a randomized trial in which the only difference between two groups of children was whether they were fed peanut protein. The study, sponsored by the National Institutes of Health and other organizations in the United States and Britain, involved infants 4 to 11 months old deemed to have a high risk of peanut allergy because they already had severe eczema or were allergic to eggs.
The infants were given skin-prick tests for peanut allergy. Those already allergic to peanuts were excluded from the study.
Some 530 children were did not have peanut allergy on that initial test. Parents of half of them were told to avoid peanuts. The other half were told to feed their children at least six grams of peanut protein per week, the equivalent of about 24 peanuts, spread over three or more meals. The preferred food was Bamba, an Israeli snack made of puffed corn and peanut butter.
The children were given another allergy test when they turned 5. Only 1.9 percent of those who were fed peanuts were allergic to them, compared with 13.7 percent of the children in the group that avoided peanuts.
An additional 98 infants had a weakly positive test when the study began, suggesting they were on their way to developing a full-fledged allergy. Among those children, only 10.6 percent of those fed food containing peanuts developed that allergy by age 5, far less than the 35.3 percent rate for children whose parents avoided feeding them peanuts.
"You got a definitive outcome, which I think is a very important thing," said Dr. James R. Baker Jr., chief executive of FARE, or Food Allergy Research and Education, an advocacy group that helped pay for the study.
There are some caveats. Parents knew which group they were in. And the study was done at a single site in London with 75 percent white children. However, the results were the same for the small number of children of other ethnic groups in the study, the researchers said.
Moreover, it is still unknown whether allergies might yet develop if the regular feeding of peanuts stopped. To test this, the children in the study were taken off peanuts after they turned 5 and are being followed for a year.
It is also unknown if the same strategy would work with other foods or for children not considered at a high risk of getting a peanut allergy. Some pediatricians said that if feeding peanut foods to children at risk was beneficial, there would be no reason to withhold such food from children not prone to allergies.
Changing practice might not be easy. "I do think parents have the highest fear of introducing peanuts," said Dr. Gupta of Northwestern. Eight years ago, she withheld peanuts from her own baby daughter, who had eczema and was allergic to eggs. The girl developed a peanut allergy. In light of the new study, Dr. Gupta said, "I'm kind of slapping myself on the wrist."
25th Feb 2015, 04:43 PM #1779
Re: Health Bulletin
Temper link to heart attack established
Scientists have confirmed that the risk of a heart attack is over nine times higher in the two hours following a burst of extreme anger.
In a study by the University of Sydney, anger was qualified as 5 and above on a 1-7 scale, referring to a state from "very angry, body tense, clenching fists or teeth, ready to burst", up to "enraged, out of control, throwing objects". Anger below this level was not associated with increased risk.
"Our findings confirm that episodes of extreme anger can act as a trigger for a heart attack. The data shows that the higher risk of a heart attack isn't necessarily just while you're angry — it lasts for two hours after the outburst. The data revealed that episodes of anxiety can also make you more likely to have heart attack," said lead author Dr Thomas Buckley from the Sydney Nursing School.
25th Feb 2015, 04:45 PM #1780
Re: Health Bulletin
Now, a 10-min strip test for Ebola, dengue
A simple paper strip similar to a pregnancy test can now diagnose Ebola in less than 10 minutes besides viral haemorrhagic fevers like yellow fever and dengue.
Unlike most existing paper diagnostics, which test for only one disease, the new strips are color-coded so they can be used to distinguish among several diseases.
The researchers used triangular nanoparticles, made of silver, that can take on different colors depending on their size. They created red, orange and green nanoparticles and linked them to antibodies that recognize Ebola, dengue fever and yellow fever. As a patient's blood serum flows along the strip, any viral proteins that match the antibodies painted on the stripes will get caught and those nanoparticles will become visible. This can be seen by the naked eye; for those who are colour-blind, a cell phone camera could be used to distinguish the colours.
Scientists from MIT say that when diagnosing a case of Ebola, time is of the essence. However, existing diagnostic tests take at least a day or two to yield results, preventing health care workers from quickly determining whether a patient needs immediate treatment and isolation.
Currently, the only way to diagnose Ebola is to send patient blood samples to a lab that can perform advanced techniques such as polymerase chain reaction (PCR), which can detect genetic material from the Ebola virus.
This is very accurate but time-consuming, and some areas of Africa where Ebola and other fevers are endemic have limited access to this kind of technology. The new device relies on lateral flow technology, which is used in pregnancy tests and has recently been exploited for diagnosing strep throat and other bacterial infections.
Until now, however, no one has applied a multiplexing approach, using multicolour nanoparticles, to simultaneously screen for multiple pathogens. For many haemorrhagic fever viruses, like West Nile and dengue and Ebola there are just no rapid diagnostics at all.
Kimberly Hamad-Schifferli took four years to develop the new device.
"When we run a patient sample through the strip, if you see an orange band you know they have yellow fever, if it shows up as a red band you know they have Ebola, and if it shows up green then we know that they have dengue," Hamad-Schifferli says.
This process takes about 10 minutes, allowing health care workers to rapidly perform triage and determine if patients should be isolated, helping to prevent the disease from spreading further.
"As we saw with the recent Ebola outbreak, sometimes people present with symptoms and it's not clear what they have," says Hamad-Schifferli.
The researchers envision their new device as a complement to existing diagnostic technologies, such as PCR.
The researchers hope to obtain Food and Drug Administration approval to begin using the device in areas where the Ebola outbreak is still ongoing. In order to do that, they are now testing the device in the lab with engineered viral proteins, as well as serum samples from infected animals.
This type of device could also be customized to detect other viral haemorrhagic fevers or other infectious diseases, by linking the silver nanoparticles to different antibodies.