Having read yet another study showing the importance of vitamin D, this time in relation to autism. I thought I'd explain more about Vitamin D as it is something we are hearing more and more on the news but I'm not sure most people fully comprehend the importance of this particular vitamin and why the NHS are now recommending supplementation for many people throughout the winter months.
Before studying Nutritional Therapy, I had of course, heard of it ('something to do with sunshine?!') but really didn't understand what or why it was so crucial. Vitamin D, like any 'vitamin' is crucial to our survival. Vitamins are required in our diet as they cannot be synthesised or made by the body. So we have to eat enough sources of (for example) vitamin C, so it can perform vital and necessary jobs around the body. In a nutshell.
[Interesting fact by the way - humans, monkeys guinea pigs and fruit bats are some of the only animals who can't make vitamin C - your dog can make it themselves, but we need to eat lots of citrus fruit and dark leafy greens!]
But vitamin D is slightly different from other vitamins. First of all technically we can synthesise it when we are exposed to enough sunlight. When we aren't getting enough (e.g. in winter, working in an office and not getting outside enough) we need to rely on dietary sources. Obviously this is a modern problem as hundreds of years ago when we spent most of the day outside and didn't slather on suncream (which incidentally blocks the UV light needed to synthesise vitamin D) vitamin D deficiency probably wasn't an issue. Nowadays the WHO believes we are facing a global health crisis with over one billion people suspected to be either deficient or suboptimal with their vitamin D levels causing incredible health problems. Some of the more minor symptoms include migraines, low energy, joint pain, recurrent infections and low mood.
Secondly, vitamin D works more like a hormone in our body controlling the absorption of important minerals such as calcium and phosphorus so of course impacts the normal growth of teeth and bones.
It also influences over 2000 genes (!!) in our body so becoming deficient, or even below optimal levels can have disastrous effects on our body and has been linked to heart disease, depression, low immunity, asthma, diabetes, bronchitis, gum disease, weight gain, osteoporosis, PMS, m/s and other autoimmune conditions and as this more recent study shows autism....
But even the richest dietary sources of vitamin D (oily fish, liver, eggs and butter) are limited in their amounts - for instance as an adult over 25 you would need to eat 200g of butter to get your recommended daily amount (not recommended in case you were wondering!) and if you are over 65 where your requirements for vitamin D go up you'd need to double that - eek!
There are two main types of vitamin D. Vitamin D2 (ergocalciferol) from plant based sources such as mushrooms and vitamin D3 (cholecalciferol) from animal sources like those listed above. Current evidence indicates that ergocalciferol is less than one third as potent as cholecalciferol.
This is obviously a problem to those wishing to follow a vegetarian or vegan diet. These people would be considered 'at risk' for becoming deficient without supplementation. I would personally not ever recommend ergocalciferol supplementation - there is a very fine line between an effective therapeutic dose and toxicity with vitamin D2 which isn't present with careful supplementation of vitamin D3. You can get vegetarian sources of Vitamin D3 supplements (made from sheeps wool!) and for vegans (made from lichen).
Other groups of people at risk from vitamin D-eficiency:
Low fat dieters
Vitamin D is also fat soluble (as is vitamin A, E and K). Meaning you need fat in your diet in order for the vitamin to travel round the body doing its good deeds. This is therefore a problem for those wishing to follow a low fat diet (not recommended by the way).
People living in northern Europe
There is also very little storage of vitamin D meaning you can get all the outdoor air and sunshine you like which is fine in summer, but in winter when UV levels from the sun are low in northern Europe, its likely you will experience suboptimal levels no matter how much you 'banked' during summer holidays.
Sorry but as we age so do our nutritional requirements change. Anyone over age 65 should consider supplementation especially during winter.
People with darker skin:
Vitamin D3 synthesis is less effective for Asian/black/mixed race populations than in caucasians due to the darker skin pigmentation - which reduces the production of vitamin D3 so more sunshine is needed.
If you feel you are at risk of becoming deficient or low in this amazing and we're-just-discovering-how-crucial vitamin then speak to me or your local Nutritional Therapist about using a supplement effectively through the colder months of the year.