Vitamin D, The sunshine vitamin for the winter blues.
The start of Autumn for the most part has been actually much warmer than I remember in previous years, which has been great while we have been in lockdown huh! But it is starting to get quite dark and gloomy now and signs are here that yes we are about to approach winter.
It’s amazing how much of an impact the sun can have on our mood huh! And these overcast days make me feel less motivated and more inclined to hibernate.
And it’s no wonder! The science and nutrition behind the sun and our mood is pretty amazing.
Sunlight and serotonin
Did you know that sunshine helps to stimulate the part of the brain that regulates melatonin allowing for an increase in serotonin the neurotransmitter that helps you feel happy?
As humans we are designed to be programmed to be outdoors working in the sun. So during the night when there is low or no light, the lack of light detected by our eyes should send a message to the brain to produce melatonin which is a sleep hormone. At the same time less serotonin is produced which allows the natural sleep cycle to kick in.
When our eyes detect sunlight, our brain receives this message to wake the body up. Melatonin production slows down and serotonin increases enough to send messages to other neurotransmitters to help the body wake up for the day.
So, how does lack of sunshine affect all of this? Although there is enough light to help us wake if it is constantly cloudy, appropriate levels of each these important neurotransmitters don’t quite reach their peak which could be why many people during these cloudy days report a feeling of “flatness”. That is they can cope with the day….but only just. Sound familiar?
Seasonal Affective Disorder (SAD)
This is a mood disorder that affects some people generally within the Autumn and Winter months due to the lack of sunshine. It is a condition that results in low mood or depression but with the key difference being that significant improvement is seen once spring and summer return. Some of the key symptoms of SAD include:
Poor sleep or insomnia
Losing interest in everyday activities
Lack of sunshine is the not the only factor that impacts our mood. You see a lack of Vitamin D also known as the “sunshine vitamin” is another key reason why we often feel gloomy in winter.
What is the sunshine vitamin?
Vitamin D is a fat soluble vitamin and is essential for our health. It is sometimes referred to as a hormone vitamin because it plays such a vital role within communication. (The main role of hormones is communication – and it is this communication that regulates different organs/systems within the body).
Vitamin D is a such a vital nutrient, but we actually only get about 10% of it from our food. It is found in mushrooms, oily fish like salmon and sardines and liver, foods that we don’t tend to consume a lot of.
The rest of our vitamin D comes from being exposed to sunlight – specifically ultraviolet B (UVB) rays. A biochemical process occurs when UVB penetrates our skin and this biochemical process activates stores of vitamin D we have in our body. The biochemical process converts stored vitamin D which is referred to as “pre” vitamin D (D2) and converts into “pro”vitamin D (D3).
Pre vitamin D is stored in our adipose (fat) tissue or in the liver. And when UVB from sunshine hits our skin, the activation of D3 occurs so that vitamin D can be utilised by the many processes in the body including:
Neurotransmitter (brain) function
Research now shows that a deficiency in the essential Sunshine Vitamin may be linked with any of the following:
Poor immune function
Arthritis and other inflammatory conditions
Depression, anxiety, schizophrenia and other brain mood disorders
Why we need this sunshine vitamin for our mood
For a long time Vitamin D was mostly associated with bone health. It is well established the role vitamin D plays for helping with calcium absorption for good bone health helping reduce the risk of osteoporosis and rickets. (Did you know research from as recent as this year shows babies in the south of the South Island are at higher risk of rickets due to low vitamin D?)
But in the last decade there has been some great leaps forward into understanding this hormonal role vitamin D has in the body in particular when it comes to the immune system, cardiovascular and brain/mood function.
Researchers have found vitamin D receptor sites located at different parts of the brain involved with cognition (process and thought) and mental illness (fear, mood, behaviour). There is a lot of growing evidence to support the need to supplement with vitamin D for not only depression but other mood and brain disorder such as dementia, Alzheimer’s disease, Parkinson’s, Bipolar and Schizophrenia and post-traumatic stress disorder (PTSD).
But that's not all! Vitamin D not only helps with neurotransmitter communication, evidence shows that the sunshine vitamin helps to protect the brain by supporting antioxidant processes in the brain as well as support the immune function within the brain protecting against vascular injury.
So… why do we need to supplement vitamin D in winter?
No UVB = No Vitamin D
You see the New Zealand Winter sun only provides us with about 10% UVB light that we need compared to that of summer. And generally these can only be achieved when the sun is at its highest between the hours of 11 and 2.
Between these hours we should be outside (in the cold) with our kit off (mostly not all!) exposing our skin for 20 minutes to get our Vitamin D. Are you kidding me? I’m in merino rugged up inside sitting in the sun if I can doing my work!
As you can see, it is actually very hard to get our natural dose of sunshine vitamin D in winter, and the further down south you go, the worse it is as there are less sunshine hours compared to the north island.
Vitamin D deficiency in New Zealand
Over the last decade there has been much debate on whether as Kiwi’s we are at risk of Vitamin D deficiency or not. However there is a lot of recent research indicating that there is a very strong risk of deficiency. And when you consider the impact this important nutrient has within the body, it would make sense to supplement. It is estimated that 1 in 3 Kiwi’s may have vitamin D levels below the recommended blood levels.
Because we can store vitamin D in the body, you may want to consider getting your levels checked first. But if you are experiencing any of the above symptoms supplementation may be helpful.
Supplements essential in winter – regardless of sunny days
Unless you think you are going to start sun worshiping in the middle of winter (brrrrrr) then supplementation is the next best option.
My favourite option is a Vitamin D with vitamin K2. A vitamin K2 article is coming soon so watch this space!
If you have any specific questions around any this topic, please email me your questions, I am more than happy to reply and give you some help around this important winter topic. firstname.lastname@example.org
Clinical Nutritionist DipNut GradCert. HPN