In the Western world, taking a daily vitamin is common, accessible, and socially accepted as being part of a ‘healthy’ regimen. Many individuals don’t think twice about taking a vitamin to supplement the nutrients they might not be getting enough of from their food. However, many of those individuals who take vitamin supplements don’t really know what the vitamins are doing for their bodies or why they’re so important. Vitamin C is a well-known vitamin typically understood to help boost the immune system and fight off the common cold. But a recent study done by Hansen, Schou-Pedersen, Lykkesfeldt, and Tveden-Nyborg in 2018 showed another very important purpose for Vitamin C: it helps with healthy brain development and spatial memory – remembering where things are in one’s environment. According to the study, as many as 15% of the Western population are still deficient in this critical vitamin, despite its accessibility through simple diet changes and/or the use of supplements.
The study used new-born guinea pigs to test the effects of Vitamin C deficiency on the brain and spatial memory, since guinea pigs have similar brains to humans. The researchers believed the results would show a clear connection between Vitamin C deficiency and problems with spatial memory, as well as decreased neurotransmitter levels – chemicals that travel within the brain like messengers – and decreased growth in a part of the brain called the hippocampus (the hippocampus plays a major role in memory and spatial recognition).
To test their theory, the researchers used 27 guinea pigs that were five to six days old. Half of the guinea pigs were given a diet with a healthy amount of Vitamin C, and the other half were given a diet low in Vitamin C. The two groups were put on their assigned diets for eight weeks, then tested for spatial memory function using the Morris Water Maze test. This test consisted of placing the guinea pigs individually in a tub of water and seeing how long it took for them to find a small platform to rest on. Then, they were tested again to see if they could remember where the platform was. Longer times in the second trial would indicate decreased spatial memory functioning. The group that was deficient in Vitamin C predictably performed worse on this test than the control group. In particular, the deficient group took longer to find the platform the first time they were placed in the water, and also didn’t show a coherent swim pattern the second time, which indicated impaired spatial memory.
A few days after the Morris Water Maze test, when the guinea pigs were 60-61 days old, they had some blood samples drawn before being humanely put down. This was necessary so the researchers could take a closer look at the brains of the two groups of guinea pigs to see if there were any differences in the size of the hippocampus, as well as other tests that weren’t possible on live guinea pigs. The hippocampus regions of the deficient group showed lower neuron count (brain cells that transmit messages through electricity or neurotransmitter chemicals) than the control group, which indicated fewer healthy connections between those cells necessary for memory. The levels of neurotransmitters in that brain area were also examined, resulting in only one significant difference between groups. There was a decrease in the 5-HIAA/5-HT ratio (two types of neurotransmitters) in the deficient group compared to the control group, which the researchers took to mean that Vitamin C might aid in the production of such neurotransmitters.
To investigate further into the theory that a lack of Vitamin C played a role in message transmission in the brain, the researchers looked at what they called ‘markers of synaptic transmission’. Neurons in the brain communicate (transfer messages) through spaces between them called synapses. The electric messages or neurotransmitter/chemical messages travel between neurons at those synapses – synaptic transmission. Markers of synaptic transmission, then, indicate when there is activity between neurons in synapses, thus indicating if messages are being communicated properly in that area of the brain. A marker called synaptophysin in the hippocampus of the deficient guinea pigs’ brains was significantly lacking compared to the control group. This marker is particularly important for learning and memory function, showing strong support for the theory that Vitamin C deficiency impairs spatial memory.
In conclusion, this study was able to show that Vitamin C deficiency in young guinea pigs can lead to improper formation of connections and chemicals in the brain which are necessary for spatial memory. Although not directly applicable to humans, the results do show a strong indication that Vitamin C could affect our memory as well. Further studies are required to confirm this; however, this study provided a solid baseline for such studies going forward. Although vitamin supplements are easily accessible in the Western world, and many of us take them regularly, the fact that as many as 15% of our population are lacking in Vitamin C means that further research and awareness of its benefits are warranted. Individuals should aim to consume as many of their needed nutrients from foods – citrus fruits such as oranges and grapefruits are especially rich in Vitamin C – use of vitamin supplements should be discussed with a doctor.
Source:
Hansen, S., Schou-Pedersen, A., Lykkesfeldt, J., & Tveden-Nyborg, P. (2018). Spatial Memory Dysfunction Induced by Vitamin C Deficiency Is Associated with Changes in Monoaminergic Neurotransmitters and Aberrant Synapse Formation. Antioxidants, 7(7), 82.
