Sunshine is the Best Medicine for Improving Mood and Lowering Depression Through Vitamin D

Vitamin D is a fat-soluble vitamin that has been studied extensively for its role in bone health but only recently has its role in mental health begun to appear. With over 70% of adults registering as Vitamin D deficient, it’s no wonder our mental health continues to be “depressing”. While we won’t explore in detail how Vitamin D can impact the integrity of the surface of our gut as well as boosting beneficial bacteria, this also highlights the importance of nutrition. A healthy gut has numerous implications on our overall health, wellness, and mental states. Not that you needed another reason to prioritize Vitamin D in your daily health regimen.

Major Depressive Disorder (MDD) has been ranked by WHO as the third cause of burden of disease in 2008 and by 2030 it is estimated to rank first. There are an increasing number of studies which link Vitamin D deficiency to depression. This is mainly due to Vitamin D’s role in melatonin and serotonin regulation, which are two hormones involved with mood.

For a long time, we thought that Vitamin D was only produced in the kidneys, which makes sense for its impact on bone health and immunity. However, we have also discovered the vitamin D precursor (enzyme 1-alpha-hydroxylase) is found in several regions of the brain which suggests an important role of vitamin D in cognitive regulation. When we look at the function of Vitamin D within the different regions of the brain, it is incredibly evident that its ability to affect neuronal function, differentiation, proliferation of precursor cells, and even the direct pathogenesis of depression has a potent impact on our mood.

How do we Increase our Vitamin D Levels?

Serum Vitamin D3 (cholecalciferol) increases rapidly when exposed to UVB, which mainly occurs between 11 am - 3 pm due to the solar zenith angle and the intensity of UVB available. Interestingly, these cholecalciferol levels during this time are naturally increased for optimal processing of these metabolites in the liver and kidneys due to the circadian nature of our organs. In other words, getting adequate sunlight exposure during the times when UVB exposure can be highest is our best method for absorbing and metabolizing Vitamin D. It has also been shown to control over 900 genes and is a key regulator of brain serotonin synthesis through TPH2 (tryptophan hydroxylase 2) which converts tryptophan into serotonin in the brain and is required due to its inability to cross the blood brain barrier.

Serotonin is referred to as the “social brain” for its ability to regulate social cognition and decision making and is commonly known to regulate brain function and behaviors. In fact, serotonin can specifically inhibit impulsive aggression toward self and others with a positive impact on mood, cognition, impulse control, and social behavior to name a few. Recent evidence also supports that serotonin may not have as much control over depression as previously thought, but most of this is related to the modulation of serotonin through SSRI’s and other anti-depressants, specifically focused on serotonin regulation.

What is scientifically evident is that Vitamin D is an important vitamin that our bodies require for many processes, including cognitive behaviors. While the jury is still out on whether Vitamin D supplements are effective, sunlight continues to be the best way for our bodies to increase our serum vitamin D levels. Essentially, we need to get outside and let the sunshine in so our vitamin D levels can escalate, thereby positively impacting our behavior and mood. There is a chemical reaction that occurs inside of our bodies when UVB is allowed to reach our skin that’s timed with the natural circadian rhythm of our organs. Nature continues to show us the way, we just have to be willing to listen.

References:

https://www.sciencedirect.com/science/article/pii/S1087079220301222

https://pubmed.ncbi.nlm.nih.gov/25713056/#:~:text=Brain%20serotonin%20is%20synthesized%20from,serotonin%20synthesis%20is%20not%20optimal.

https://faseb.onlinelibrary.wiley.com/doi/epdf/10.1096/fj.14-268342

https://pubmed.ncbi.nlm.nih.gov/35637805/

https://pubmed.ncbi.nlm.nih.gov/25713056/#:~:text=Brain%20serotonin%20is%20synthesized%20from,serotonin%20synthesis%20is%20not%20optimal.