This article was originally published as a guest editor post at foodpharmacy.se
You’ve probably heard plenty about how stress, social isolation, negative emotions and a lack of joy have a negative impact on health. What if we turn it around: can positive emotions, fun and social connectivity influence our well-being in a positive way? Since this article is part of a series on immune function, I also wonder if joy could even make us more resistant to infections?
The study of the relationship between the nervous and immune system is called psychoneuroimmunology or immunopsychiatry. Nerve activity and immune function interact in complex and intricate ways. For example, our nervous system is directly connected to the bone marrow and thymus. The bone marrow is the site of origin for new immune cells, and the thymus is the location where some of them mature. Furthermore, our immune cells have means of reacting to changes in concentrations of neurotransmitters. Neurotransmitters are the signaling molecules of our nervous system, and control how neurons behave. Let’s have a look at what this all means for us in our daily lives.
Laughing for health
There’s the famous story of Norman Cousins who laughed himself into remission of his autoimmune disease (1). Although that’s a n=1 experiment and is likely to be a bit of an outlier, there might be support of fun and joy being a beneficial immune modulator.
If you haven’t tried it yourself, you’ve seen it on TV; a laughter therapy class. It may seem a bit odd to many of us, but these people may in fact be on to something. Researchers who study psychoneuroimmunology often use natural killer (NK) cell activity as an indicator of how well the immune system is functioning. NK cells are a type of immune cell with antiviral and anti-cancerous properties. In particular, NK cells are important in the fight of viral infections such as herpes, epstein barr (mononucleosis) and influenza. One study concluded that not only does mirthful laughter increase emotional well-being and reduce stress, but it also improves the activity of NK cells (2). When exposing study participants to humorous content such as funny videos, some research groups also observed immune enhancing effects (3).
Connectedness can come in many different forms, such as nature, pets and fellow humans. Research shows that having access to social support improves many aspects of physical health, including immune function. (4) In a recent research review (5), the authors are looking at social interactions and immune function from an evolutionary perspective and conclude that “positive experiences of social connection may reduce inflammation and bolster antiviral responses.” Surrounding ourselves with people we enjoy spending time with may be very important to health. Did you know that you may be able to boost your immune system, simply by looking at someone you like? (6)
Owning a pet can also be a fantastic way of finding connectedness, joy and of benefitting from its effects on our health. Human-animal interactions can have a positive impact on mood, stress resilience, anxiety, depression, blood pressure, heart-rate variability, pain, and immune function. Researchers suggest that the “love and cuddle hormone” oxytocin may be the main mediator of these effects. (7)
How about connecting with nature? One universal way of nurturing joy is exposing oneself to green, natural surroundings. Many studies have concluded that spending time in nature is positive for emotional well-being and a number of general health parameters. A team of researchers found that 10-50 minutes in a natural environment had a positive effect on mood, focus, blood pressure and heart rate. (8, 9). But can it also boost our defence against infections? Seemingly, it might. A Japanese research group has found that “forest bathing” (i.e. immersing oneself in a natural environment) might have a positive effect on immune alertness by increasing both the number and the activity of NK cells (10). Spending time in nature might also exert other positive effects on immune function and inflammation. (11)
Hobbies boost your biology
The positive effect of hobbies on general health has been observed in a study which saw that hobbies might extend longevity. (12) Music and singing is a universal source of joy and a common hobby across all human cultures. Music can increase a large number of different immune cells, including NK cell activity. It’s even been proposed that music therapy can re-balance an immune system in someone afflicted by stress. (13) What’s fascinating is that increased immune responses have also been observed in rodents who get to listen to music. (14) I don’t know if scientists can make rodents sing, but many people report that singing makes them happy. According to researchers ”singing can cause changes in neurotransmitters and hormones, including the upregulation of oxytocin, immunoglobulin A, and endorphins, which improves immune function and increases feelings of happiness.” The positive effect on physiology may involve many different mechanisms, for example strong emotions, social connectivity, and stimulation of the vagus nerve which in turn has calming and anti-inflammatory effects. (15)
Thinking about it, it’s tricky to distinguish the main reason a particular hobby is beneficial to health. For example, an outdoor hobby might include all of the following factors: exposure to natural environment, physical activity, physical touch, pets, laughter, creativity, friendship and a sense of community, meaning and belonging. Not to mention exposure to immune-modulating microbes and sun . Also, many of these things have in common that you are forced to exit your own mind for a while, and focus on something other than the problems and struggles of yourself and the rest of the world, in that regard somewhat similar to meditation.
Tipping the balance
Life-threatening infections, autoimmune disease, cancer and other immune-related conditions often arise as a result of complex underlying causality, and the triggers of ill health can be powerful. I’m not suggesting that taking up a hobby can cure serious illness. However, if we look at it all as tipping the balance in our favour, it makes sense to make more space for joy in our lives.
The populations of the world’s blue zones are fascinating examples of the idea of tipping the balance. Blue zones are longevity hotspots, where people lead healthier lives than the rest of the world. Researchers have studied their lifestyle in detail. Extensive social support, a sense of community and spending time on hobbies are thought to be three of the reasons the blue zone inhabitants can look forward to long, healthy lives. (16)
For some of the discovered connections exemplified in this article, more research is needed to truly verify the findings, and some areas report inconsistent findings. Nevertheless, many do seem to point in one and the same direction ‒ doing things that makes us feel good also does good. Simply put, joy makes us healthy. Could there be any better news than that?
You find the other articles in the 7 part series ”For king and country – Tend to your immune system” here: