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  • Writer's pictureNarelle

Vitamin D-lightful: 8 Sunny Side-Up Facts About the Sunshine Vitamin


The sky is grey, the winter woolies are coming out, the boots are unboxed which means …


Time to start your Vitamin D supplementation.


I will admit I am a big “fan girl” of Vitamin D, the sunshine vitamin.  It is just the all rounder super star of the vitamin world, and not just for immunity.


So I thought I would share 8 very cool facts and uses for Vitamin D other than for immunity.


  1. Vitamin D is technically not a vitamin.

It is actually more like a hormone inside the body that interacts with our genes.  In almost every cell and tissue of our body, and in all major organs,  there are Vitamin D Receptors (VDR) or binding sites.  Plus these VDR binding sites can be found throughout the genome controlling a lot of our genes and there are over 800 genes in the body (and counting) for which there is a Vitamin D response element. In other words, it has a role in regulating genes. It just floats around and attaches to cells via the VDR and turns them on or off.  And this helps regulate many body processes.


  1. Most of our Vitamin D is absorbed through the skin from sunlight

This makes Vitamin D uniques in that it is synthesised in the human body through the action of sunlight.

But we can only make Vitamin D in the skin when the sun is high enough in the sky, the UV index is 3 or more, the skin is uncovered and free from sunscreen and you are not too close to either Poles (again to do with how high the sun is in the sky).


To make it simple, expose your arms and legs and live above 33 degrees latitude to get Vitamin D most of the year round.  Sadly Melbourne is only just above as is Sydney so we get very little if any D during winter.


An easy way to work out if you are getting Vitamin D from the sun is by comparing your shadow to your height.  If your shadow is shorter then you are synthesising vitamin D.   If your shadow is longer than your body won’t synthesis vitamin D.


But do avoid getting burnt.


  1. We can’t get enough Vitamin D from foods

It is very difficult to obtain adequate amounts of vitamin D from food sources (unless you are part of an indigenous North American population such as the Inuits who consume oily fish, whale blubber, seal blubber and polar bear liver).


Only a few foods contain Vitamin D and only in small amounts.  And the foods aren’t taste bud ticklers for many people - cod liver oil, oily fish (especially sardines), egg yolks and traces in dairy products and I must say I am not a huge fan of many of these foods but each to their own..


  1. 50% of the population is thought to have low levels and most people assume they are getting enough.

In Australia at least 25% have low levels of Vitamin D but that percentage rises to 50% of Victorians and Taswegians who see less sunlight during winter, 42% of South Australians and about 29% of New South Welsh-people.


Deficiency is more common in women, darker skinned people, the obese and the elderly.


Remembering too, a deficiency is when low levels can lead to illness or a pathology.  It is not an optimal level.  The optimal level is thought to be around 150nmol/L, or at least over 100nmol/L.


  1. Vitamin D is implicated in obesity

Overweight people tend to have lower vitamin D levels - a higher BMI and body fat percentage are associated with lower Vitamin D levels. And it seems that overweight people need more Vitamin D than normal weight people to reach the same blood levels.


But losing weight, even small amounts can affect your Vitamin D levels and lead to a  modest increase in blood levels of Vitamin D


Some evidence shows that increasing Vitamin D in the blood can reduce body fat and boost weight loss so it may aid weight loss.   It seems to suppress the storage and formation of fat cells which basically makes it hard for fat to form in your body in the first place.


Plus it increases serotonin which plays a role in appetite control, and increases testosterone which can trigger weight loss.


  1. Vitamin D is vital for bone health and to prevent bone disease like osteopenia and osteoporosis.

Vitamin D is essential for optimal absorption of calcium from the gastrointestinal tract.  Along with Vitamin K and Magnesium it helps “lock” the calcium into the bone tissue.  So you can get all the calcium you need but without Vitamin D you may not absorb enough and then get it in the bones to keep them strong.


  1. Vitamin D has a role in gut health.

It keeps things tight!


Our small intestine has junctions that need to be tight to reduce intestinal permeability.  If those junctions are loose then it lets in things that are not meant to be there like partially digested food stuff and bacteria.  This can lead to leaky gut and a variety of digestive disorders.


Plus Vitamin D regulates the immune response and may contribute to a thriving flourishing gut microbiome.


  1. Having low levels is linked to bad moods and poor sleep

Adequate Vitamin D plays a role in serotonin production and serotonin helps regulate mood and sleep.  Plus it has a role in melatonin production which is also needed for sleep.


So low levels could be making you grumpier.


Interestingly Seasonal Affective Disorder is due to a drop in serotonin which is caused by reduced sunlight and may be triggered by changing levels of Vitamin D across the winter.


So you can see Vitamin D is fairly crucial to our health and wellbeing.


Depending where you live, during winter levels naturally decrease in the majority of people due to the decreasing exposure to sunlight.  Most people are not able to achieve the amount of winter sun exposure for maintaining vitamin D adequacy and even those who do are unlikely to maintain adequate Vitamin D levels.


So my message for winter is to ensure you have adequate Vitamin D levels to accommodate this decline and consider taking Vitamin D supplements. Talk to me about the best one to take for you.


Don't forget to take your Vitamin D supplements with food, preferably a fatty food so you are enhancing the absorption.



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