A study from the University of British Columbia has found that biochemical reactions that give rise to Alzheimer's disease could start as early as during pregnancy or just after birth if the newborn does not receive enough vitamin A.
Published in the journal Acta Neuropathologica, the study employed mice models and demonstrated that supplements administered to newborns with low vitamin A levels could also be effective in slowing down the neurodegenerative disease.
For the study, Weihong Song and colleagues built upon results from earlier works linking low vitamin A levels with impairments in cognitive ability. Using mice models, the researchers examined the effects of vitamin A deficiency in the womb and during infancy. They chose these early developmental stages because these are critical periods in a child's growth as these are the times when brain tissues are "programmed" for the rest of a person's life.
Based on their findings, the researchers saw that even a mild form of vitamin A deficiency is capable of spurring amyloid beta production, which gives rise to plaque that smother and eventually kill neurons in patients diagnosed with Alzheimer's disease. Additionally, mice subjects deprived of vitamin A did worse on standard memory and learning tests as adults.
The researchers also observed that when mice deprived of the vitamin in the womb were given normal diets as pups, they still recorded worse performance than those who received sufficient vitamin A in the womb but were deficient after birth. This observation points to the conclusion that damage was already in place in the womb.
Possible Effect Reversal
While damage may already be present as early as during pregnancy, some level of it may still be reversed by providing vitamin A supplements right away after birth to reduce levels of amyloid beta in the brain. Mice subjects that followed this ended up with improved learning and lesser memory deficits compared to those who were not given supplementary aid.
"It's a matter of the earlier, the better," said Song.
However, while the researchers highlight the importance of receiving adequate vitamin A, they also want to reiterate that the deficiency is not common in North America and that excessive intake of the vitamin could also bring negative effects. Instead of taking vitamin A supplements, pregnant women are advised to focus on consuming a balanced diet to get all the nutrients they need.
Other Study Results
Alongside clarifying the connection between vitamin A deficiency and Alzheimer's disease, the study also provided evidence that there is a link between the vitamin and developing dementia in later years. The researchers examined 330 elderly individuals in Chongqing and saw that 75 percent of the subjects with significant or mild levels of vitamin A deficiency had impaired cognitive abilities, compared to 47 percent who received had normal levels of vitamin A.
Partly funded by the Canadian Institutes of Health Research and the National Natural Science Foundation of China, the study included work from Jiaying Zeng, Tingyu Li, Zhe Wang, Jie Chen, Qian Chen, Lan Ren, Zhen Fan, Yili Wu, and Hongpeng Jiang.