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Biochemical reactions that cause Alzheimer’s disease
could begin in the womb or just after birth if the
fetus or newborn does not get enough vitamin A,
according to new research from the University of
British Columbia.
“Our study clearly shows that marginal deficiency of
vitamin A, even as early as in pregnancy, has a
detrimental effect on brain development and has
long-lasting effect that may facilitate Alzheimer’s
disease in later life,” said Dr. Weihong Song, a
professor of psychiatry and Canada Research Chair in
Alzheimer’s Disease.
For this research, Song built on previous studies
that have linked low levels of vitamin A with
cognitive impairments.
In collaboration with Dr. Tingyu Li and others at
Children’s Hospital of Chongqing Medical University,
they examined the effects of vitamin A deprivation
in the womb and infancy on Alzheimer’s model mice.
These early developmental stages are crucial periods
during which brain tissue is “programmed” for the
rest of a person’s life.
The researchers found that even a mild vitamin A
deficiency increased the production of amyloid beta,
the protein that forms plaques that smother and
ultimately kill neurons in Alzheimer’s disease. He
also found that these mice, when deprived of vitamin
A, performed worse as adults on a standard test of
learning and memory.
Even when the mice deprived of vitamin A in the womb
were given a normal diet as pups, they performed
worse than mice who received a normal amount of the
nutrient in the womb but were deprived after birth.
In other words, the damage had already been done in
the womb.
Still, Song and his collaborators also showed that
some reversal is possible: Mice who were deprived in
utero but then given supplements immediately after
birth performed better on the tests than mice who
weren’t given such supplements.
The study, published today in Acta Neuropathologica,
also included new evidence in humans of the vitamin
A-dementia connection in later years.
Examining 330 elderly people in Chongqing, Song and
his collaborators found that 75 per cent of those
with either mild or significant vitamin A deficiency
had cognitive impairment, compared to 47 per cent of
those with normal vitamin A levels.
However, Dr. Song cautions against overreacting to
this news.
Vitamin A deficiency, though common in many
low-income regions of the world, is rare in North
America, and excess intake of the nutrient could be
harmful.
Pregnant women in particular should not take
excessive vitamin A supplements. A balanced diet is
the best way to ensure adequate levels of the
nutrient.
For more information
Acta Neuropathologica
Marginal vitamin A deficiency facilitates
Alzheimer’s pathogenesis
Link...
The University of British Columbia
Link...
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