The Star Online: Lifestyle: Health
The Star Online: Lifestyle: Health |
- Why polar bears are fat, yet healthy
- Why do mums kill their children?
- TV habits during pregnancy affect child obesity
| Why polar bears are fat, yet healthy Posted: 17 May 2014 09:00 AM PDT Scientists studying polar bears say that one day, the polar bear 's digestive secrets could help boost human health in an age of increasing obesity. When it comes to healthy eating, polar bears break all the rules. They eat mostly fat, but they don't get heart disease the way humans would. The reason lies in their genes, said scientists in the journal Cell. Some speedy evolutionary tricks, particularly in the genes that handle how fats are metabolised and how fats are transported in the blood, have allowed polar bears to survive in the Arctic, scientists said. And it all happened within the last 500,000 years, after the polar bear split from its cousin, the brown bear, according to research that compared the two animals' genomes. Scientists found that polar bears are much younger than previously thought, with past estimates of the divergence time between polar and brown bears ranging from 600,000 to five million years ago. "It's really surprising that the divergence time is so short," said Rasmus Nielsen, a University of California (UC), Berkeley, United States, professor of integrative biology and of statistics. "All the unique adaptations polar bears have to the Arctic environment must have evolved in a very short amount of time," he said. It's unclear what drove polar bears to evolve into a separate group from brown bears, though it happened at a time that coincides with a warm interglacial period that could have encouraged brown bears to venture further north than they had in the past, researchers said. Then, when conditions cooled again, a group of brown bears may have become isolated, and forced to adapt to a snowy and cold new environment. Polar bears eat mostly seals, which are rich in blubber, and they nurse their young with a milk that is nearly one-third fat. About half the bears' overall weight is made up of fat, rather than muscle and bone. In contrast, a healthy person's body fat percentage could range between eight and 35%. "The life of a polar bear revolves around fat," said Eline Lorenzen, a researcher at UC Berkeley and one of the lead authors on the study. "For polar bears, profound obesity is a benign state," she added. "We wanted to understand how they are able to cope with that." Researchers compared the blood and tissue samples from 79 polar bears from Greenland to 10 brown bears from Sweden, Finland, Glacier National Park in Alaska, and the Admiralty, Baranof, and Chichagof (ABC) Islands off the Alaskan coast. They found one of the most strongly selected genes was APOB, which in mammals encodes the main protein in "bad" cholesterol, known as LDL (low density lipoprotein), and allows it to move from the blood into the cells. Changes in that gene hint at how the polar bear is able to manage high blood sugar and triglycerides at a level that would be perilous in people. Scientists on the study, who hailed from Denmark, China and the US, said one day, the polar bear's digestive secrets could help boost human health in an age of increasing obesity. "The promise of comparative genomics is that we learn how other organisms deal with conditions that we also are exposed to," said Prof Nielsen. – AFP Relaxnews |
| Why do mums kill their children? Posted: 17 May 2014 09:00 AM PDT IN Raijon Daniels' short eight years of life, his Richmond mother, Teresa Moses, beat, starved and washed him with household chemicals and high-pressure hoses. In 2009, Judith Williams drove her 16-year-old son to the top of Mount Diablo State Park, shot him in the back and head, and then turned the .357 revolver on herself. And last month, Ashley Newton, a young San Jose mother, was arrested on suspicion of fatally stabbing her seven-month-old son with a pocket knife in a Livermore park. Maternal filicide – mothers killing their own children – is rare, experts say, but each time it occurs, the horrific crime raises the question: How could it happen? "Mothers don't kill their children unless they are seriously disturbed," said Dr Lanny Berman, executive director of the American Association of Suicidology in Washington. "I think it gets attention because, one, it's unfathomable, and two, it's sensational, and obviously, the media reports on that. But it should be noted that this is not common. It is very rare." Rare as it is, there's clearly something about the mother-child relationship that can go badly wrong. According to the United States Department of Justice, women commit only 14% of all violent crimes in the US. But a recent study on filicide shows they commit nearly half of all parental murders. A 2014 Brown University study analysing 32 years of filicide arrests found there are about 3,000 instances annually in the US where a parent kills a child. Investigators have not released a suspected motive for Newton, only saying it was not a murder-suicide attempt. She was arraigned recently at John George Psychiatric Hospital in San Leandro, where she was being held for an undisclosed "medical issue". She did not enter a plea. Evidence at the scene suggested Newton may have been depressed, police said, and one witness who rendered aid to the mortally-wounded infant said he could tell the mother, caked in blood, was in "a really bad place". "If there is indeed no suicidal behaviour on her part, then typically, it's homicidal behaviour associated with a psychotic break or postpartum depression," Dr Berman said. Studies and experts agree on one common factor when mothers commit such an unthinkable crime: extreme mental illness. Dr Phillip Resnick, an expert in maternal filicide and a co-author of a 2007 World Psychiatry study, reviewed psychiatric studies on mothers killing their children and found most had depression, psychosis and suicidal thoughts. He identified five motives: ·"Altruistic filicide", the most common motive, where a mother rationalizes that killing her child is in the child's best interest. ·"Acutely psychotic filicide", where a mother kills without an understandable motive, possibly hearing voices. ·"Fatal maltreatment filicide", where a mother does not necessarily mean to kill her child, but the death occurs after cumulative abuse. ·"Unwanted child filicide", where a mother believes her child is a hindrance in her life. ·"Spouse revenge filicide", the rarest for mothers, where she kills her child to emotionally strike out against the father. Recognising the special nature of the crime, other countries have infanticide laws that reduce the penalty for mothers who kill their children. British law allows mothers to be charged with manslaughter, rather than murder, if they have a mental disorder. Women who are convicted of infanticide there often receive probation and mental health treatment referrals, rather than incarceration, according to Dr Resnick's report. On Oct 19, 2005, Lashaun Harris, who, the week before, told family members she was going to feed her three small children to sharks, travelled with her kids to San Francisco, walked to the end of Pier 7, and threw her children into the Bay. The 23-year-old homeless Oakland mother with a history of schizophrenia and other mental illnesses told police she heard voices telling her to throw her children into the water so they could reunite with God in heaven. "What I learned with Lashaun Harris was she was a good mother, and she wouldn't have killed her children without her mental illness," said Teresa Caffese, the former San Francisco public defender who represented Harris. "Heaven to her was a concrete place with basketball courts, buses, you name it." "The system sometimes does not sufficiently help the mentally ill," she said. A jury acquitted Harris of first-degree murder, but found her guilty of three counts of second-degree murder. A judge declared her criminally insane and sentenced her to a psychiatric hospital, where she will remain unless she regains her sanity. Last year, Teresa Moses was released from Napa State Hospital after doctors determined she was no longer a risk to society. According to a 2011 report by the US Department of Justice that studied homicide trends from 1980 to 2008, 63% of all murdered children under age five were killed by a parent; 33% by fathers and 30% by mothers. The US has the highest rates of child homicide, and when a young child is murdered, it is most likely a parent who did it, according to Dr Resnick's research. In the case of infanticides – children killed under the age of one – such as the Livermore case, Dr Resnick's study found women perpetrators were often unemployed mothers in their early 20s. Newton has no job and is 23, police said. Dr Resnick also found that those rates increased with economic stress and social isolation, and offenders also experienced psychiatric disorders. Newton is originally from North Carolina, but has lived in Fremont and San Jose with no other family in the immediate area, police said. "Unless there's a really unusual circumstance, a mother doesn't kill her children," Caffese said of the Newton case. "I bet there were signs all along that were just missed." – Contra Costa Times/McClatchy-Tribune Information Services |
| TV habits during pregnancy affect child obesity Posted: 17 May 2014 09:00 AM PDT EXPECTANT mothers can help prevent childhood obesity early by adopting healthy screentime habits even before the child is born. That's the overriding conclusion of a new study presented at the recent Pediatric Academic Societies meeting in Vancouver, Canada, where researchers said that women who ate in front of the TV during meal times while they were pregnant, were five times more likely to expose their infants to TV during feeding times than their counterparts. "Reinforcing healthy media habits during pregnancy may help reduce infants' mealtime media exposure, and impact long-term media habits in children," said lead author Mary Jo Messito. For their study, researchers analysed data from an early childhood obesity prevention programme conducted for low-income Hispanic families at Bellevue Hospital Center/NYU School of Medicine in New York, United States. Mothers were followed until the babies were three years old. During their third trimester, 71% of the 189 participants reported watching TV during "some" meal times (compared to options like "never", "often" and "always"), while 33% of mothers said their three-month-olds were also exposed to TV during feedings. "Identifying specific maternal behaviours and characteristics associated with child TV viewing during meals will help early childhood obesity prevention efforts seeking to promote responsive feeding and limit TV exposure during infancy." The latest research builds on a body of work that has shown a link between increased screentime, poor eating habits and obesity. – AFP Relaxnews |
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