Friday, December 27, 2013
Why you should eat nuts in pregnancy: Now doctors say it lowers risk of baby developing allergy
I proposed this about a year ago -- JR
Children could have a lower risk of developing a peanut allergy if their mothers eat more nuts in pregnancy, researchers claim. Their study adds to growing evidence that eating nuts while expecting a baby has no damaging effect on the unborn child.
Those with peanut allergies can develop breathing problems if they eat or come into contact with nuts. The most severely affected are at risk of life-threatening anaphylactic shock.
Mothers-to-be were previously advised to avoid peanuts, especially if there was a history of allergies such as eczema or asthma in the family, for fear of the baby developing a sensitivity to nuts. One in seven who are sensitive go on to develop allergies.
But now doctors see little harm in peanuts and other nuts, unless the mother herself already has an allergy. In the latest study, researchers looked at data held on 8,205 children.
Some 308 had food allergies. Of these, 140 were allergic to peanuts, which are part of the legume family, or ‘tree nuts’, such as almonds, brazils, cashews, hazelnuts and pistachios.
The findings showed children whose mothers ate peanuts or other nuts five times a week or more had the lowest risk of developing an allergy.
However, this benefit was not found among children of those who had a nut allergy, according to the study published in medical journal JAMA Pediatrics.
Study leader Dr Lindsay Frazier, of the Dana-Farber Children’s Cancer Center in Boston, said: ‘Our study supports the hypothesis that early allergen exposure increases the likelihood of tolerance and thereby lowers the risk of childhood food allergy.’
Dr Ruchi Gupta, of the Northwestern University Feinberg School of Medicine in Chicago, said the study showed that women should not restrict their diets during pregnancy.
‘Certainly, women who are allergic to nuts should continue avoiding nuts,’ she said. ‘Pregnant women should not eliminate nuts from their diet as peanuts are a good source of protein and also provide folic acid, which could potentially prevent both neural tube defects and nut sensitisation.’
The number of British children allergic to peanuts has doubled in the past 20 years for reasons which remain unclear.
Until recently parents were advised to avoid giving children peanuts until the age of three in a bid to reduce allergies. Women are now told they can eat peanuts, or food containing peanuts, during pregnancy unless they are allergic to them or a health professional advises against it.
Indeed some doctors believe exposure to peanuts early in life primes a child’s immune system which defuses the threat of developing an allergy.
Dr Adam Fox, a consultant children’s allergist at Guy’s and St Thomas’s NHS Foundation Trust, said: ‘The results of this study are interesting but contradict other studies that have either shown no effect of nut consumption during pregnancy or suggested a possible risk from increased consumption.
'To make things even more complicated, there is also strong evidence to suggest that nut allergy doesn’t develop until after birth and that it is exposure of the infant’s skin to nut protein that is most important in the development of allergy.’
He said the latest international guidelines suggested ‘no need to either avoid nuts, nor to actively eat them’.
Teenagers who smoke cannabis have 'poor memory and abnormal brain structures'
This is suggestive but not proof. Maybe inadequate people are more likely to use MJ
Teenagers who use cannabis regularly risk damaging their memory, scientists say – in turn leading to poor academic performance.
They believe the brain abnormalities last for ‘at least a few years’ after users have stopped taking the drug.
The researchers also said there was fresh evidence the habit may cause mental health problems in youngsters predisposed to schizophrenia.
Marijuana is the most commonly used illicit drug among adolescents in the UK, with more than four in ten admitting having taken it.
Almost 100 teenagers took part in the US research examining the effects of cannabis deep in the brain. It found teenagers who smoked it daily for about three years had abnormal changes in the brain structures related to remembering and processing information and they performed poorly on memory tasks.
The brain abnormalities and memory problems were found on MRI scans when study participants were in their early twenties – two years after they had stopped smoking the drug.
Memory-related structures in their brains appeared to shrink and collapse inward and the researchers said such damage was linked to poor academic performance and everyday functioning.
The study also shows the marijuana-related brain abnormalities look similar to those seen in schizophrenia patients.
Lead author Matthew Smith, a professor in psychiatry and behavioural sciences at Northwestern University Feinberg School of Medicine, Chicago, said: ‘The study links the chronic use of marijuana to these concerning brain abnormalities that appear to last for at least a few years after people stop using it.
‘With the movement to decriminalise marijuana, we need more research to understand its effect on the brain.’ He said chronic cannabis use may lead to changes in brain structure associated with having schizophrenia.
Of the 15 marijuana smokers who had schizophrenia in the study, 90 per cent had started using the drug heavily before they developed the mental disorder.
Professor Smith added: ‘If someone has a family history of schizophrenia, they are increasing their risk of developing schizophrenia if they abuse marijuana. ‘If you have schizophrenia and you frequently smoke marijuana, you may be at an increased risk for poor working memory, which predicts your everyday functioning.’
The study, published in the journal Schizophrenia Bulletin, is the first to target key brain regions in the deep grey matter of chronic marijuana users with MRI scanning.
It is also the first time abnormalities in these regions have been linked with an impaired working memory – the ability to remember and process information in the moment and then transfer it to long-term memory.
Participants started using marijuana daily aged 16-17 for about three years – and had been free of the drug for around two years at the time of the study.
The 97 teenagers who took part included healthy people, those with a marijuana use disorder and schizophrenia patients.
The younger the individuals were when they started chronically using marijuana, the more abnormally their brain regions were shaped, suggesting parts related to memory are more susceptible to the effects of the drug if abuse starts at an earlier age.
Under the Labour government cannabis was downgraded from class B to class C in 2004, which critics argued gave the ‘green light’ to use by youngsters. The decision was reversed in 2008 when ministers decided to overturn official scientific advice and return it to class B.
Posted by jonjayray at 12:29 AM