Vitamin D – Should I Have my Levels Tested?
All vitamins are important but because vitamin D is essential for so many body processes, low levels of this nutrient can lead to wide ranging health problems.
In this article we’ll take a closer look at vitamin D, and why you should get tested.
Functions of Vitamin D
Almost every cell in your body has receptors for vitamin D, which affects your gene expression when it binds to these receptors. In this way it can reduce chronic inflammation, which has far-reaching effects on the body.
Vitamin D increases absorption of calcium and plays a role in bone health, so low levels can be connected with osteoporosis as well as rickets in children. This disease is now at its highest level since the 1960’s.
It’s a pity we don’t see the sunshine in autumn because at this time of the year when colds and flu are taxing our immune system we need vitamin D all the more. This is because of its role in supporting immunity and improving our resistance to infection. Rather than simply boosting our immune system, it’s thought vitamin D regulates its function, in other words supporting the immune system if it’s under functioning but preventing it from becoming overactive. Because of this, it’s believed vitamin D may reduce the likelihood of developing autoimmune diseases such as lupus, rheumatoid arthritis, Type 1 diabetes and multiple sclerosis.
Vitamin D is known to be involved in regulating cell growth and division. In this way it may help to prevent the development of cancer cells. It also appears to protect heart health. Men with low levels of vitamin D have an increased risk of heart attack.
Finally, vitamin D is important for brain health. Low levels are associated with increased risk of dementia, Alzheimer’s and Parkinson’s disease.
Sources of Vitamin D
Only a few foods naturally contain high levels of vitamin D. It’s found in oily fish, egg yolks and meat, especially organ meats. We obtain the vast majority when we expose our skin to the UVB rays in sunlight.
Researchers found when volunteers were exposed to 13 minutes of simulated midday summer sunshine, while dressed in clothes which exposed one third of their skin to the sun, 90% of the participants saw their blood levels of vitamin D increase.
Vitamin D is produced in doses of UV light below those which cause skin reddening – little and often exposure to sun is best at encouraging its production by your body.
However, how much vitamin D we make in response to sun exposure does depend on our skin colour and our age, meaning people with darker skin, the elderly and people who cover their skin for religious reasons are at greater risk of vitamin D deficiency. Widespread use of sunblock to guard against skin cancer and spending more time indoors in the winter also means we naturally make less vitamin D.
Vitamin D Deficiency is Widespread
The British Nutrition Foundation estimates more than a fifth of us in the UK are deficient in vitamin D. In the USA it’s very different, with a staggering 70% of the population believed to be low in this vitamin. The discrepancy may lie with recommended blood levels of vitamin D, which differ from country to country.
How to Test for Vitamin D
Blood tests measure a substance from which the body makes active vitamin D, known as a precursor. In the UK, current advice is if your blood level is lower than 25mnol/l, (nanomoles per litre of blood), you are deficient.
However, this figure relates to the level of vitamin D needed to avoid having a deficiency and may be a lot less than the desirable amount for optimum health. There’s no standard definition of the optimal level of vitamin D. Some sources believe anything above 50nmol/l is sufficient, while others believe 70-100nmol/l is optimal for health.
However, these figures are by no means straightforward not least because it’s believed our genes may play a role in how effectively we can utilise the vitamin D precursor.
The process which produces vitamin D from sunlight is regulated so we don’t produce too much. That means even extensive sun exposure doesn’t lead to overly high levels of vitamin D in the blood. This isn’t the case with supplementation, when excess vitamin D can lead to a build–up of calcium in the body.
However vitamin D does not work in isolation and optimum intake does appear to depend on our intake of other nutrients like vitamins A and K.
Functional Medicine and Vitamin D
If you would like support on your personal journey towards optimal health, a Functional Medicine consultation can assess your personal vitamin and mineral status by using functional testing combined with a full health history.
You’ll be provided with nutritional recommendations to correct any deficiencies, along with lifestyle strategies to address imbalances in the body. Why not book an appointment by clicking here