Nutrient during pregnancy 'super-charges' brain
13:05 12 March 04 http://www.NewScientist.com news service
Taking a nutrient called choline during pregnancy could "super-charge" children's brains for life, suggests a study in rats.
Offspring born to pregnant rats given the supplement were known to be faster learners with better memories. But the new work, by Scott Swartzwelder and colleagues at Duke University Medical Center in North Carolina, US, shows this is due to having bigger brain cells in vital areas.
Choline, a member of the vitamin B family, is found in egg yolks, liver and other meats - "exactly the kind of things people were told not to eat" due to their high cholesterol content, says Swartzwelder.
He believes their results in the rats could translate to humans, and indeed the US Institute of Medicine added choline to the list of essential nutrients, particularly for pregnant women, in its 2003 recommendations.
The implications of the study's findings are "potentially huge" Swartzwelder believes: "If it turns out that it's true in humans and can make people smarter their whole lives and forestall age-related memory decline - that's potentially a very exciting prospect."
Anatomy and physiology
Behavioural studies have shown giving choline to pregnant rats improves learning and memory in their offspring. The pups also suffer significantly less from failing memories as they get old.
However, it was not known whether choline's effects were on the general brain environment or whether it fundamentally changed the brain's cells.
"Our study is the first time anyone has shown that prenatal choline supplementation actually changes the anatomy and physiology of single brain cells," Swartzwelder told New Scientist. No adverse effects could be seen in the rats, he adds.
The team gave pregnant rats three to four times their normal intake of choline for six days. Gestation lasts about 21 days in rats, and the period during which the rats were fed extra choline roughly corresponds to the start of the third trimester in women.
The pups born were raised to adulthood and then their brains were examined, in particular the hippocampus - the area of the brain critical for learning.
This part of the brain was sliced in a way that preserved its internal circuitry and kept it alive. A tiny electrode was then used to recording the behaviour of each cell.
The neurons of rats born to mothers given extra choline fired electrical signals more rapidly and for longer periods, indicating a capacity to communicate more easily.
The team then injected a biological dye into the neurons to look at their shape and structure. The cells from rats receiving prenatal choline supplements were substantially bigger than those from rats that did not.
"We are looking at consistent changes in the range of 20 to 25 per cent," says Swartzwelder. "These are bigger cells with more dendrites, the areas of the cell specific to receiving incoming signals." He says the combined changes induced by choline in the physiology and anatomy of the brain cells would "hotwire" the system.
The team does not know exactly how choline boosts brains, but it is known to contribute to the building of cell membranes during the embryo stage of development. "My bet is it has something to do this," Swartzwelder says.
Previous work by Steven Zeiser at the University of North Carolina has shown choline alters a crucial gene by adding a methyl group on to it. This switches off the gene, CDKN-3, which usually inhibits cell division in the memory regions of the brain.
There is little information on how much choline women currently take. "But don't be afraid of eggs," Swartzwelder suggests. "I used to eat a low fat diet - I've started eating eggs and I'm not even pregnant!"
Journal reference: Journal of Neurophysiology (vol 91 April issue)