Saturday, February 04, 2012

Taking fish oil during pregnancy 'protects babies from eczema'

The great fish oil religion again. This is actually a fairly dishonest piece of work. As you will see from the appended journal article there was NO DIFFERENCE in overall allergy sensitivity at the end of the experiment.

But a bit of data dredging turned up a couple of reactions which looked marginally significant. If they had used the proper experiment-wise error-rate approach to significance testing even those effects would have vanished, however.

Taking fish oils during pregnancy could protect your unborn baby from eczema, scientists say. In tests, children whose mothers took omega 3 supplements were a third less likely to develop the dry skin condition. They were also 50 per cent less likely to develop an intolerance to eggs before their first birthdays.

The Australian scientists believe that omega 3 fatty acids passed on to via the placenta affect the unborn baby’s immune system which protects against eczema.

Researchers at Adelaide University studied 706 pregnant women with a family history of allergies. Half were given fish oil supplements to take three times a day from 21 weeks into the pregnancy until the birth. The others were given vegetable oil.

More research is needed to see if fish oils protect against asthma and hay fever, the British Medical Journal reported.

The Government advises pregnant women not to eat more than four portions of fish a week as high levels of mercury can be dangerous to the baby.


Journal article follows:


Effect of n-3 long chain polyunsaturated fatty acid supplementation in pregnancy on infants’ allergies in first year of life: randomised controlled trial

By D J Palmer et al.


Objective: To determine whether dietary n-3 long chain polyunsaturated fatty acid (LCPUFA) supplementation of pregnant women with a fetus at high risk of allergic disease reduces immunoglobulin E associated eczema or food allergy at 1 year of age.

Design: Follow-up of infants at high hereditary risk of allergic disease in the Docosahexaenoic Acid to Optimise Mother Infant Outcome (DOMInO) randomised controlled trial.

Setting: Adelaide, South Australia.

Participants: 706 infants at high hereditary risk of developing allergic disease whose mothers were participating in the DOMInO trial.

Interventions: The intervention group (n=368) was randomly allocated to receive fish oil capsules (providing 900 mg of n-3 LCPUFA daily) from 21 weeks’ gestation until birth; the control group (n=338) received matched vegetable oil capsules without n-3 LCPUFA.

Main outcome measure: Immunoglobulin E associated allergic disease (eczema or food allergy with sensitisation) at 1 year of age.

Results: No differences were seen in the overall percentage of infants with immunoglobulin E associated allergic disease between the n-3 LCPUFA and control groups (32/368 (9%) v 43/338 (13%); unadjusted relative risk 0.68, 95% confidence interval 0.43 to 1.05, P=0.08; adjusted relative risk 0.70, 0.45 to 1.09, P=0.12), although the percentage of infants diagnosed as having atopic eczema (that is, eczema with associated sensitisation) was lower in the n-3 LCPUFA group (26/368 (7%) v 39/338 (12%); unadjusted relative risk 0.61, 0.38 to 0.98, P=0.04; adjusted relative risk 0.64, 0.40 to 1.02, P=0.06). Fewer infants were sensitised to egg in the n-3 LCPUFA group (34/368 (9%) v 52/338 (15%); unadjusted relative risk 0.61, 0.40 to 0.91, P=0.02; adjusted relative risk 0.62, 0.41 to 0.93, P=0.02), but no difference between groups in immunoglobulin E associated food allergy was seen.

Conclusion: n-3 LCPUFA supplementation in pregnancy did not reduce the overall incidence of immunoglobulin E associated allergies in the first year of life, although atopic eczema and egg sensitisation were lower. Longer term follow-up is needed to determine if supplementation has an effect on respiratory allergic diseases and aeroallergen sensitisation in childhood.


Drug addiction 'may be hereditary' as siblings have brain abnormality which makes self-control difficult

Drug users hooked on crack cocaine may have inherited their vulnerability to addictive behaviour, scientists claimed yesterday.

Researchers found that drug addicts and their non-addicted siblings share certain features of the brain, meaning it may be hard-wired for addictive behaviour.

Scientists who scanned the brains of 50 pairs of brothers and sisters of whom one was a cocaine addict found that both siblings had brain abnormalities that made self-control more difficult.

The findings increase understanding of why some people with a family history of drug abuse have a higher risk of addiction than others. The study could also help vulnerable people lean how to take control before addictions set in.

However, the work by the University of Cambridge also suggested that although there may be a genetic base for addiction, some people can overcome this predisposition to stay off drugs.

A study in the Lancet medical journal in January said that as many as 200 million people use illicit drugs worldwide each year, with use highest in wealthy countries.

Unhealthy addictions can also range from narcotics and prescription medicines to legal substances like cigarettes and alcohol and lifestyle factors such as over-eating or gambling.

Scientists have noticed brain differences in drug addicts before, but as yet they were not sure whether those differences came before the drug use, or were as a result of it.

Karen Ersche of the Behavioural and Clinical Neuroscience Institute at Britain's Cambridge University led a team of researchers who got around this problem by studying pairs of biological siblings - one addicted and one with no history of chronic drug or alcohol abuse - and comparing both siblings' brains to those of other healthy people.

Their results, published in the journal Science, showed that both addict and non-addict siblings shared the same abnormality in the parts of the brain linked to controlling behaviour - regions known as the fronto-striatal systems.

'It has long been known that not everyone who takes drugs becomes addicted, and that people at risk of drug dependence typically have deficits in self-control,' said Ersche.

'Our findings now shed light on why the risk of becoming addicted to drugs is increased in people with a family history:... Parts of their brains underlying self-control abilities work less efficiently.

Paul Keedwell a consultant psychiatrist at Britain's Cardiff University, who was not involved in the research but was encouraged by its findings, said: 'If we could get a handle on what makes unaffected relatives of addicts so resilient we might be able to prevent a lot of addiction from taking hold.'


No comments: