The immune system is constantly working every day to maintain the body’s defense against foreign substances like viruses and bacteria.
Not only does the immune system function to fight off illness and disease, but it is also involved in many other cognitive and behavioral functions within the body.
Here, we’ll breakdown some of the cognitive and behavioral functions that involve the immune system, and emphasize why it is important to maintain optimal immune function.
Support Learning and Memory Processes in the Brain
The immune system is made up of several components that help regulate inflammation in the body1.
One way this system regulates inflammation, wound healing, and removal of foreign particles is through the signaling activity of small proteins called cytokines2.
Various cytokines have been shown to play key roles in cognitive functions like learning and memory.
One of the fundamental processes thought to be involved in learning and forming new memories is synaptic plasticity3. This is where neurons strengthen and modify their connections with one another.
In the brain, nerve cells called neurons send signals to one another to relay information. Accordingly, the better these neurons can send these signals, the more efficient the brain becomes at performing its various functions.
Importantly, studies have shown that cytokines are involved in regulating molecular mechanisms that play a key role in synaptic plasticity.
For example, the pro-inflammatory cytokine TNF-α has been shown to modify the strength of neuronal connections by increasing the number of proteins responsible for receiving signals from neurons. These proteins are called AMPA receptors4.
In other words, for a neuron to send a signal to another neuron, it sends a molecular message which needs to bind to AMPA receptors located on the other neuron. By increasing the amount of these AMPA receptors, the receiving neuron now becomes much more efficient at receiving the necessary information.
Similarly, another pro-inflammatory cytokine called IL-1β also appears to be necessary for synaptic plasticity. One study found that blocking IL-1β activity actually stopped one of the major processes involved in driving synaptic plasticity5.
Anti-inflammatory cytokines are also important in this process. Specifically, the anti-inflammatory cytokine TGF-β is very important and almost necessary in strengthening plasticity and that blocking activity of this cytokine can make rodents become forgetful6.
Conversely, long-term elevations in pro-inflammatory cytokines have been shown to cause negative effects on memory processes like forgetfulness in animal studies7.
Thus, the role of inflammation in learning and memory appears to be highly refined, in that adequate immune activity is necessary for these processes, but too much can be detrimental.
This is why it is important to keep the immune system in check, especially while learning a new skill or remembering things.
Combat the Effects of Stress
We all deal with stress in our daily lives. The most prominent stress in humans is likely psychological stress—things like constantly remembering to meet deadlines, pay bills, timing our commute to work, balancing work and family life, and/or getting our kids to soccer practice after work.
Psychological stress is everywhere. Importantly, however, these relatively short activations of the stress response system are meant to help us during times that are considered to be challenging and difficult to deal with8.
In fact, this short-term stress response—which may occur when trying to race home from work to get your kid to their soccer or baseball practice—has been associated with enhanced immune function8.
But, if stress is prolonged and continues for a period of time, the stress response system cannot fully and adequately recover, which dampens the enhanced immunity that normally happens during short bouts of stress.
And, if prolonged even further, the immune response actually begins to decline9,10,11.
As stress is constant and is likely to be experienced in more than one way every day of our lives, it is very important to maintain an optimal immune function to combat the possible negative effects that are associated with chronic stress.
Boost Immunity to Stay Sharp and Fight Stress
We may not always be able to avoid chronic stressors, but we can certainly boost immunity by incorporating anti-inflammatory foods into our diets like omega-3-rich fish, berries (i.e., elderberry, blueberry), and broccoli to name a few12,13,14.
At the same time, when dealing with stress, it is especially important to avoid foods that can cause inflammation, which happen to be high in saturated fats and carbohydrates (i.e., also referred to as comfort food—interesting how that works, isn’t it?)15.
Finally, immune boosting supplements and regular exercise—even mild to moderate housework, gardening, or a brief walk around the block—are both excellent ways to maintain adequate immune function, which will likely help you stay sharp during those business meetings and feel better when dealing with everyday stressors in the environment.
As always, consult your physician before making any significant changes to your diet and/or lifestyle.