Monday, March 16, 2009

Thicker myelin aids IQ!

Not exactly where you would initially look for the genetic basis of IQ. That IQ is polygenetically determined, however, is undoubted

A study has found that the thickness of the insulation of our brain's white matter is directly linked to IQ. Memory, self-control, planning, logic and mathematical ability are all linked to the quality of myelin sheath that protects nerves of white matter from damage, according to New Scientist magazine. Scientists at the University of California in Los Angeles examined the brains of 23 sets of identical twins and the same number of fraternal twins using a new type of magnetic resonance imaging scanner called HARDI.

MRI scans usually show volumes of different tissues in the brain by measuring the amount of water present. HARDI determines water levels diffusing through white matter - an indirect measurement of myelin integrity.

The research also found that inherited genes play a greater role in intelligence than was previously thought [Thought by whom? IQ has been known to be mainly hereditary for around 100 years]. Genes appear to affect intelligence by influencing how well nerve fibres are encased in protective and insulating fatty myelin. A good covering of myelin results in faster nerve impulses. "It's like a picture of your mental speed," chief researcher Professor Paul Thompson told New Scientist magazine.

Identical twins share the same genes while fraternal twins share about half their genes. Comparing the results from each showed that myelin integrity was genetically determined in many parts of the brain important for intelligence. They include the corpus callosum, which brings together signals from the left and right side of the body, and the parietal lobes responsible for visual and spatial reasoning and logic. Myelin quality in these areas correlated with scores from tests of abstract reasoning and overall intelligence.

Dr Richard Haier, from the University of California at Irvine, who worked on the research, said the findings did not mean intelligence could not be improved. "It's just the opposite," he said. "If it's genetic, it's biochemical, and we have all kinds of ways of influencing biochemistry." In future there might be a way to identify the genes involved and enhance their activity, he said. This in turn could lead to treatments for multiple sclerosis, autism and attention deficit disorder, which are all associated with lack of myelin.


Fruit-juice drink has sugar in it! Horrors!

Maybe sugar should be banned from restaurants and cafes too. Who needs sugar in their tea or coffee?

It claims it has "no bad stuff" but children are being warned to avoid a new fruit juice drink. One Sydney school has even taken the extraordinary step of hiring a dietitian to talk to parents and experts have slammed the makers of Golden Circle LOL No Bad Stuff for preying on children. Teachers became alarmed after spotting students as young as six drinking the carbonated fruit juice for breakfast.

Bankstown Grammar School is so concerned about the effects on children it is calling on parents to stop allowing the drink in lunch boxes. The private school has already banned Coke and Mars bars but still finds the sugary sweets creeping into students' bags. "We could try banning it (LOL) but we have tried before on other products and kids still end up bringing them in," principal Terry Lidgard said. "I would rather educate the students ... like harm minimisation."

Manufactured by a leading fruit juice company, the cans of drink contain 26gm of sugar. Emblazoned with large smiley faces and colourful labelling, the drinks have come under fire for looking like caffeine energy drinks such as Red Bull and V. The Children's Hospital at Westmead dietitian Susie Burrell criticised Golden Circle for preying on kids. "They have a big enough market, they don't have to target children like this. It is marketed in a way that makes it look healthy," she said. Golden Circle was contacted but did not respond.

US research advises kids should not consume more than two sweetened drinks a week. "Fruit juice contains sugar and this is highly concentrated. It is bad for teeth. It contains no other nutritional value," Ms Burrell said. "Parents should be giving their children flavoured milk [Really? Milk is highly calorific!] or water." At least one in four children in Australia is overweight.


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