Here is a bit of info .....well a lot really ! , about Vitamin D.
Yes , amongst many symptoms of D deficiency is fatigue and tiredness , lethargy, muscle aches and pains , joint pains , etc.
In the UK , at our latitude , 50 degrees plus , the suns elevation, in winter never goes above 45 degrees in the sky, this means that UVB , the high energy light which produces Vitamin D in our skin is absent from Mid October to Mid April. So we have a 6 month period when we cannot make vitamin D in our skin from sunlight. This is just physics , it has been proved by various bodies. Light of wavelength shorter than 320 , i.e. UVB is absorbed by the long pathlength through the atmosphere in winter. So , if your shadow is shorter than you , in summer, then, the suns elevation is greater than 45 degrees and you <strong>can</strong> make vitamin D . If your shadow is longer than your height , then you <strong>cannot</strong> make Vitamin D. So , even in summer ,,,, before about 11 in the morning and after about 3 in the afternoon, you cannot make vitamin D. Again, this is all just physics.
Food is quite a limited source of Vitamin D . It is a fat soluble vitamin , so it is NOT found in any fruits or vegetables at all. It is not found in most foods unless they have been specifically fortified. Some countries do mandate some fortification , i.e. the USA , we in the UK, however, do not. You will find a very few items with a very low level of fortification, but not many at all. Eggs contain about 40 IU each. A very very low level , enough for a chick to develop, but not enough to satisfy our needs. Oily fish is one of the best sources , wild salmon being a prime example , also mackerel etc. However, to get sufficient , you would need to consume that fish every day. Humans evolved to make their own Vitamin D in skin, in strong sunlight. When we sunbathe in strong sun , we can make 10,000 to 20,000 IU in 20 mins , if you are white skinned. If you are dark skinned it will take 3 to 5 times longer , to make the same amount. Skin pigment acts as a sunscreen. Sunscreen creams and lotions , can prevent UVB from reaching the skin cells which make vitamin D . If you apply factor 15 or more , you can reduce your Vitamin D production in that skin by 97%.
Many people in this country have low levels of vitamin D , for the reasons outlined above. Our blood levels are generally 1/2 to 1/4 that which prevailed throughout human evolution in Africa, where sunlight is strong enough to make vitamin D all year round. Our migration from Africa , (approx 45,000 years ago) has meant that our bodies need to adapt to lower light levels. It is only 10,000 years ago , at the end of the last ice age , that we moved into Northern Europe, and became white. Evolutionary pressure caused this adaptation to spread throughout our Northern population. Darker skin inhibits the production of Vit D , so darker skinned individuals would be less able to survive. Vitamin D is an essential micro-nutrient. It becomes a hormone in the body , it enables genes in every cell in your body to be read , it enables those cells to function properly. About 2000 of your genes are affected. That is about 10% of your entire genome. Low vitamin D is associated with a myriad of illness, from short latency , like rickets , to long latency like osteoporosis osteopenia etc etc. In evolutionary terms , 10,000 years is short , we have not evolved our physiology to cope with low vitamin D. It is true we have had a few genetic mutations i.e white skin , which is a single gene mutation , however every cell in our body carries a receptor for vitamin D. If you lived and worked in sunlight , like our ancestors , you blood level would rise to their level, as has been shown in modern day humans , lifeguards etc. Our modern lifestyle pre-disposes us to low vitamin D , our latitude means that we will be low vitamin D , unless we take steps to alleviate it.
If you think you are deficient , then have a look over here , where you will find many people that have been diagnosed with Vit D deficiency , their stories, how it affected them , how it was treated. What effect it had etc.
www.mumsnet.com/Talk/general_health/2421492-Vitimin-D-can-it-have-this-effect
I have posted quite a few times here on Mumsnet , with information/ latest research into this Vitamin, search my nick, if you are interested !
.