The vitamin that isn’t a vitamin at all! ☀️
According to the World Health Organisation (WHO), 3.3bn years (measured in DALYs *) might be lost across the globe, annually, due to disease arising as a result of a complete lack of sunlight! [1]. However, you could argue that we wouldn’t be here at all without sunlight, not just due to disease but also a lack of any life at all.
There are many short-comings in the report, not least because it doesn’t consider all disease, including mental health concerns, however it is an interesting representation of the significance of sunlight. The point that the WHO are trying to make is that insufficient exposure to sunlight results in a variety of disabilities, or diseases, that reduce life expectancy or impair quality of life to such an extent that they would be devastating to the human population. So what are the benefits of sunlight?
Why is the sun so special?
The benefits of sunlight exposure on the human body include:
- synthesis of vitamin D by the body;
- production of serotonin, via the activity of vitamin D, which is a mood-boosting and calming chemical;
- governing the 24-hour circadian clock in the brain, through altering serotonin and melatonin levels, and
- inducing release of endorphins.
Vitamin D
Vitamin D is no longer considered a vitamin at all, but a hormone. It is very difficult to find a reliable statistic on how many people are deficient in vitamin D in the UK. The UK Government say 1 in 6 people are deficient and should supplement their diets as a result. However, I would say it is much more prevalent, and some respected scientists go as far as saying about 50-60% of people have insufficient levels.
The issue in calculating deficiency is partly because we cannot agree what is an optimal level. As a result, it is also difficult to know what is an appropriate amount to supplement. In addition, we cannot know our current vitamin D levels without testing them, and there are many variables including seasonality and diet that affect them.
Scientists are still working to understand the importance of vitamin D. We do currently know that Vitamin D is essential for many processes in the human body, including:
- maintaining bone health, through calcium and phosphorus regulation;
- supporting immunity;
- preventing and fighting cancer;
- protecting cardiovascular function;
- reducing inflammation, which is the lead exacerbator of many conditions including autoimmune disease like rheumatoid arthritis, type 1 diabetes mellitus and multiple sclerosis;
- mental health conditions like depression, anxiety, bi-polar disorder, autism, Attention Deficit Hyperactivity Disorder (ADHD), Seasonal Affective Disorder (SAD), panic attacks, Pre-Menstrual Syndrome (PMS) and suicide.
In fact, it is now known that over 1,000 genes, affecting almost every tissue in the body, are modulated by the active form of vitamin D. Given the widespread effect of the vitamin, we can see how important it is in general human health, both physical and mental.
Circadian rhythm
Vitamin D is important in the production of serotonin. As we discussed in previous blogs, serotonin is produced during the day, and is converted to melatonin in darkness. These neurotransmitters regulate the sleep-wake cycle, which also affects digestion, hormonal activity, inflammation, infection and immunity including modulating autoimmune conditions, cancer and other important bodily functions. All of these also have an indirect role to play in conditions like depression and anxiety.
Early morning exposure to sunlight especially, is now known to trigger melatonin production at night, which helps to promote restful sleep and mitigate mental health problems associated with insufficient sunlight or vitamin D.
Endorphins
Endorphins are the feel-good chemicals that our body produces, which we discussed here. I don’t know about you, but I notice the endorphins immediately when I’m out in the sunshine, and just like the head of a sunflower turns towards the sun, so does my face! 😊🌻
Seasonal Affective Disorder (SAD)
SAD especially seems to be triggered by a drop in daily sunlight exposure and is most prevalent during the winter months of countries further away from the equator. Vyssoki et al reviewed over 16,000 suicides in Austria and confirmed the highest incidences occurred between March and May. This pattern isn’t fully understood. You might imagine the highest number of suicides would be in the depths of winter. Some scientists suggest it relates to the suddenness of the increase in serotonin release due to greater sun exposure [3]. Personally, I consider it might be more likely to do with the length of time for which a person has had insufficient exposure to sunlight, from October through to the spring. By the time we reach spring, the accumulated effect of the lack of exposure to the higher intensity sunlight is greatest.
Mental health treatment
Currently, UV therapy, which mimics the sun’s rays, is used as a treatment for poor mental health, however it is not currently available on the NHS. It involves using a light box (a lamp) that emits a high intensity of light, of ideally at least 10,000 lux, which simulates sunlight and triggers the release of serotonin. This is found useful in SAD especially in the darker months of the year, and also non-seasonal depression.
We recommend great care when buying yourself a light box as they may not filter out the harmful UV-rays.
Caution
Sunlight contains different types of ultra-violet (UV) rays including UVA (longest wavelength), UVB and UVC (shortest wavelength). It is the UVA rays that are most ageing and the highest cause cancer. UVA is most prevalent in the winter months. UVB rays are more likely to cause DNA damage and skin cancer but are important for the synthesis of vitamin D and all the benefits previously mentioned [2].
Nevertheless, clearly we should ensure we obtain an optimum level of sun exposure. The best advice I can give is to obtain full-body sun exposure for about 15 to 20 minutes a day between 10 am and 2 pm daily in the summer. You would need to do this without sunscreen to obtain the benefits; otherwise the rays are filtered out (although not completely). You may want to use sunscreen on your face. I would always recommend building up sun exposure slowly, especially where sunscreen is not used. I do not advocate using chemical sunscreens as research shows they may cause cancer. I recommend using a physical (mineral) sunscreen containing either zinc oxide or titanium dioxide instead.
What else can we do?
During the winter months in the colder climes, it is recommended that we supplement with vitamin D to support our bodies, and some suggest adults should take as much as 4,000IU/100 micrograms (depending on level of melanin in the skin, diet, daily sun exposure, latitude and use of sunscreen). This is quite a lot more than the 400IU/10 micrograms currently recommended by the NHS in the UK. High doses of vitamin D should be taken with caution due to the effect on calcification in the body, especially the kidneys and heart and how it may negatively affect the bones. It is a good idea to obtain vitamin D from our diets. Fatty fish (salmon, mackerel, sardines and herring), liver and eggs are a great source.
As you have seen, sunlight forms another of our powerful toolkit for good mental health. As spring (and the associated showers!) are well and truly here and the clocks have changed, we can all benefit from more sunlight at last. We recommend trying to get outside into the sunlight every day to obtain maximum benefits, and as early as possible in the morning as this will trigger earlier melatonin production in the evening and help you sleep.
We have so much more information to share with you and will be doing so on a fortnightly, rather than weekly, basis in future. We’re always here for you, so in the meantime, feel free to reach out to us.
Enjoy the longer days.
Well wishes,
Andie. x
* Measured in DALYs, which measure how much a person’s expectancy of healthy life is reduced by premature death or disability caused by disease. 1 DALY represents one lost year of 'healthy' life. The sum of these DALYs across the population, or the burden of disease, can be thought of as a measurement of the gap between the current health status and an ideal health situation where the entire population lives to an advanced age, free of disease and disability. For a full explanation, visit: https://www.who.int/data/gho/indicator-metadata-registry/imr-details/158
[1] Benefits of Sunlight: A Bright Spot for Human Health, M. Nathaniel Mead, Environ Health Perspect. 2008 Apr; 116(4): A160–A167
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290997/
[2] Solar ultraviolet radiation: Global burden of disease from solar ultraviolet radiation, World Health Organisation, Environmental Burden of Disease Series, No. 13
https://www.who.int/publications/i/item/9241594403
[3] Effects of sunshine on suicide rates, Vyssoki et al, Comprehensive Psychiatry, 2012 Jul;53(5):535-9, PMID: 21821241