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Nutrient during pregnancy 'super-charges' brain
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."
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)
Shaoni Bhattacharya