A billion people worldwide are deficient in vitamin D!
Vitamin D is a really important vitamin which actually acts more like a hormone and is involved with bone health, metabolism, thyroid health and immune health to name a few roles! Deficiencies have been linked to respiratory infections, cancer and autoimmune disease.
Our main source of vitamin D is through exposure to UVB rays from the sun on our skin. When these rays hit the skin, vitamin D is synthesised from cholesterol. In the U.K. we can’t get enough vitamin D from the sun between the end of October and the end of March to enable this synthesis to happen.
In addition, there are many different factors which might hinder your ability to make vitamin D.
Medications such as laxatives, steroids (such as prednisone), cholesterol-lowering drugs (such as cholestyramine and colestipol), seizure-control drugs (such as phenobarbital and phenytoin), tuberculosis drug (rifampin), weight-loss drug (orlistat).
Kidney disease impacts your levels as the kidneys play a central role in vitamin D metabolism. Being overweight or obese affects your ability to make vitamin D. Older people might find it more difficult too as the ability to generate vitamin D through the skin decreases with age.
Having darker skin is a key factor affecting vitamin D levels. People with darker skin will need significantly more sun exposure to produce vitamin D than those with lighter skin.
Not enough sun exposure either from not getting out or due to where you live will impact levels, as will wearing sunscreen – which has been shown to reduce vitamin D levels, if applied properly and consistently. The angle of the sun, lattitude, altitude, pollution and cloud cover will all impact how much UVB rays reach the ground and therefore how much vitamin D you can make.
Certain conditions such as crohn’s disease, cystic fibrosis and coeliac disease can reduce your ability to absorb vitamin D.
Weight gain in perimenopause, can impact our ability to absorb vitamin D. Then as oestrogen declines this can also impact vitamin D. Research shows women who have low oestrogen often have low vitamin D and those with higher vitamin D have higher oestrogen.
Vitamin D helps boost oestrogen utilisation at receptor sites (we have oestrogen receptors all over the body) and increases hormone production in general so it’s important you have optimum levels.
Because everyone will have different abilities to make and absorb and even transport vitamin D, then you will require a dose dependent on that. So the best way to determine this is to do a test to find your starting level. Then, if you are deficient or not at an optimal level, you need to supplement accordingly to get that level up. Then retest after 8 weeks. Be sure to test a couple of times a year to understand your levels and how much you need to take to keep them at a sufficient level. Consider working with your doctor or a registered nutritional therapist if you can, to guide you on supplement levels. Aim for a blood vitamin D level of around 75 to 100. The NHS recommend no more than 4000iu per day for adults although this depends on what your vitamin D status is when you start supplementing. If your levels are reasonably high then 4000iu could be way too much for you and you don’t want to over supplement as that can also be problematic.
Some foods have vitamin D, oily fish, eggs, cod liver oil, mushrooms, BUT you can’t get enough from food so supplementation is the best option.
