Vitamin A, vitamin D, and omega-3 for the brain’s neurons and development

- throughout life

Neurologists agree that the brain’s neurons constantly change in relation to stimuli from the inside and outside environment. That is how we learn new skills and develop our memory. The brain’s ability to adapt and change is called neuroplasticity and doctors have suspected for a long time that it takes place in the synapses. A team of scientists from the University of Freiburg in Germany has discovered that a vitamin A-like compound affects the neurons and their ability to adapt to structure and function. The scientists hope that their discovery can contribute to the development of new therapies for treating brain disorders. Earlier studies have shown that omega-3 fatty acids, vitamin D, and lifestyle in general also affect the brain’s neuroplasticity and development.

The human brain contains around 100 billion neurons that collectively control our thoughts, feelings, behavior, and movements. Neurons control all the impressions that we are exposed to inside and outside our bodies. The huge network of brain neurons and our information management is therefore a precondition of good health. Neurons consist of a cell body (soma) and two types of branches: The dendrites that receive signals and the axons that transmit signals.
The point of contact between two neurons is called the synapse, and signals are transmitted by means of electric impulses or neurotransmitters such as glutamate, serotonin, dopamine etc.
The plasticity of neurons is a measure for their ability to change and adapt as a result of interaction with thoughts, behavior, and environment. For instance, when we learn something new or become better at making a specific movement, new connections are established between the neurons, while existing connections are amplified.
Neuroplasticity is developed in the fetal stage and continues throughout life. Some connections are strengthened, while others are weakened. It all depends on how they are used. The neuroplasticity theory replaces the previous assumption that the brain and neurons are unable to change after a person reaches a certain age. The scientists also believe that understanding the cellular and molecular mechanisms that represent the brain’s plasticity – or its ability to learn, change, and develop – is vital for the prevention and treatment of many different diseases and conditions.

Retinoic acid, brain health, and brain plasticity

The University of Freiburg researchers wanted to study how the neuronal dendrites change if they are exposed to retinoic acid, which is a derivate of pure vitamin A (retinol). The dendrites, as mentioned earlier, receive signals from other neurons in their synapses, and because they constantly have to relate to countless stimuli, they play a key role in brain plasticity. For example, learning something new can change the number and shape of dendrites. However, such changes are also observed in diseases like depression and dementia.
It is already known that retinoic acid plays a key role in cellular growth and cell differentiation. In the new study, the scientists found that retinoic acid is able to increase the size of the dendrites and improve signal transmission between the neurons. They concluded that retinoic acid is important for the neurons’ plasticity in the human brain. This new discovery may help understand synaptic plasticity and contribute to the development of new therapeutic strategies for treating brain diseases such as depression.
In the study, the scientists used small tissue samples of the brain cortex that had been collected in connection with surgery. Afterwards, the brain tissue was treated with retinoic acid and the functional and structural properties of the neurons were analyzed by means of electrophysiological and microscopic techniques. The new study is published in eLife.
When the neuroplastic changes cause physical changes in the synapses, certain nutrients are needed to form the new connections.

Vitamin D and memory

All cells in the body have vitamin D receptors (VDR), including neurons and cells in the hippocampus, which is the part of the brain that controls our memory, learning, and sensory input. Vitamin D is considered a neuroactive steroid hormone that has a particularly important role in the brain and in the formation of new connections between neurons.
Scientists from the University of Queensland, Australia, have found in earlier studies that vitamin D affects a type of network in the brain called perineuronal networks. These networks constitute a strong and supportive structure around certain neurons. That way, these networks stabilize the interneuronal contacts.
The scientists also found a possible link between lack of vitamin D and loss of brain plasticity. When they depleted healthy mice of vitamin D they found after 20 weeks that the mice’s ability to remember and learn dropped significantly. Furthermore, there was a large reduction in the number and strength of neuronal connections in the hippocampus of the mice. According to Professor Thomas Burne, who conducted the study, loss of plasticity and functions in this part of the brain can contribute to the development of schizophrenia, including loss of memory and distorted perception of reality
Vitamin D plays a great but overlooked role in brain health, and other studies have shown that a deficiency of this nutrient also increases the risk of anxiety, depression, dementia, Alzheimer’s disease, autism, and other neurological disorders. It certainly doesn’t help that around one billion people worldwide are believed to lack vitamin D.

Omega-3 fatty acids counteract brain inflammation

The brain contains large quantities of omega-3 fatty acids that are found in the membranes of the neurons, among other places. The form of omega-3 called DHA (docosahexaenoic acid) plays a key role in the development of the human brain and intelligence. It also supports the formation of new connections between neurons and improves synaptic plasticity. DHA is important for the activity in hippocampus throughout life.
EPA (eicosapentaenoic acid), another type of omega-3, counteracts inflammation that can damage healthy cells and cause depression. It seems that omega-3 fatty acids in general are vital for a healthy brain and support healthy ageing and brain plasticity.
A rich source of EPA and DHA is oily fish so it is a good idea to follow the dietary guidelines for fish consumption or to take a fish oil supplement. There is also omega-3 in linseed oil, rapeseed oil, and walnuts, but it is in the form of ALA (alphalinolenic acid) that must be converted into omega-3. Many people have difficulty with this conversion because their enzyme processes are sluggish.

Physical activity, brain exercise, and a good night’s sleep

Many studies show that it is easier to learn something new and remember it if you are physically active right before or after the actual learning process takes place. That is why physical activity is so important for neuroplasticity.
Also make sure to get enough sleep. When you sleep, your brain removes toxic waste from all the daily activities at a cellular level. Healthy sleep helps us recharge physically and mentally and makes it easier for the brain to sort impressions from the day so our memories function better. The neuroplastic changes that are started during the day continue in your sleep. The brain prefers a regular 24-hour rhythm and it is best to get 7-8 hours of uninterrupted sleep. Also, avoid exposure to unnecessary light and electrosmog just before bedtime and try to sleep in complete darkness to support the natural rhythm of the body and brain.

References:

Maximilian Lenz et al. All-trans retinoic acid induces synaptic plasticity in human cortical neurons. eLife, 2021

University of Freiburg. Vitamin A for nerve cells. ScienceDaily. March 31, 2021

University of Queensland. Potential Link Between Vitamin D Deficiency and loss of Brain Plasticity. Neurosciencenews.com 2019

Alexander Muacevic and John R Adler: The Role of Vitamin D in Brain Health: A Mini Literature Review. Cureus 2018

Debora Cutuli. Functional and Structural Benefits Induces by Omega-3 Polysaturated Fatty Acids During Aging. Current neuropharmacology. 2017

Neuroplasticitet – hjernens foranderlighed. Elsass Fonden
Elsass Fonden - Neuroplasticitet, CP og hjernens foranderlighed