A new study from the University of British Columbia finds that vitamin A deficiency in newborns or even while in the womb can lead to Alzheimer’s disease later in life.
Essential for growth and development of the body’s immune system and vision, Vitamin A deficiency in the early years is a global health problem, affecting 250 million preschool children worldwide. The World Health Organization includes Vitamin A on its list of Essential Medicines and says an estimated 250,000 to 500,000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight.
But Vitamin A, which actually comprises a range of fat-soluble organic compounds including retinol and beta-carotene, and its effects on learning and neural development are still being explored, with past studies on rodents showing that Vitamin A supplementation given to Vitamin A-deficient rodents improves learning and memory and can help combat cognitive declines associated with aging.
The UBC study goes one step further and traces the origins of the neurodegenerative impairments known as Alzheimer’s disease and dementia to Vitamin A deficiencies in the womb and just after birth.
“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, professor of psychiatry at UBC and Canada Research Chair in Alzheimer’s Disease.
Researchers found that mice deprived of Vitamin A in the womb had increased production of amyloid beta, a protein implicated in the development of plaque and neuron death associated with Alzheimer’s disease. These Vitamin A-deprived mice were also found to perform more poorly on learning and memory tests.
Interestingly, mice who had been deprived in the womb and later given a normal diet as pups ended up performing poorer on cognitive tests than mice who received a normal intake of Vitamin A in the womb but were deprived after birth, thus showing the integral role that Vitamin A plays at the very earliest stages of development.
Nevertheless, supplementation after being deprived did have a positive effect, say the researchers, who found that mice deprived in utero but later given supplements performed better on cognitive tests than the Vitamin A-deprived mice who were not given supplements. “In some cases, providing supplements to the newborn Alzheimer’s disease model mice could reduce the amyloid beta level and improve learning and memory deficits,” said Song. “It’s a matter of the earlier, the better.”
An estimated 564,000 Canadians are currently living with dementia, with 25,000 new cases being diagnosed every year. An aging population means that the number of people living with dementia in Canada is expected to double in 20 years.
Dr. Song cautions readers of the new study that Vitamin A deficiency is a relative rarity in the industrialized world and that taking too much Vitamin A can potentially be harmful, especially for pregnant women. Vitamin A is found in foods such as liver, eggs, carrots, broccoli and leafy greens.