Vitamin D Deficiency - Cambridge Nutritional Sciences

Vitamin D Deficiency

Throughout the winter months, the majority of us within the UK are subject to reduced sun exposure, which can in turn lead to a lack of vitamin D. This is because our main source of vitamin D is through its production within the skin, in response to direct exposure to sunlight. As there are often no obvious symptoms associated with this deficiency, it is important to monitor vitamin D levels, especially in the winter months when daylight is reduced. Individuals who spend more time indoors or who live in areas of high pollution or inner-city areas where large buildings block sunlight, are at risk of vitamin D deficiency. The same can be said for individuals who frequently use sunscreen when out in the sun, who have darker skin, or who have an impaired ability to produce vitamin D (e.g. the elderly).

Inadequate levels of vitamin D can make individuals more susceptible to serious and wide-ranging conditions such as cardiovascular and autoimmune disease, osteoporosis, rickets, osteomalacia, strokes, nervous system disorders, as well as diabetes to name but a few (Holick, 2003; Poole et al, 2005; Khazai et al, 2008; Wrzosek et al, 2013; Dankers et al, 2017; Narasimhan and Balasubramanian, 2017). Breast (Shao et al, 2012), prostate (Trump and Aragon‑Ching, 2018) and colon cancer (Klampfer, 2014), as well as depression (Penckofer et al, 2010; Spedding, 2014) have also been linked to vitamin D deficiency and in addition, this nutrient is key to ensuring the health and integrity of the gut lining (He et al, 2018). In fact, vitamin D is known to affect more than 2000 genes in the body and thus is often referred to a ‘pro-hormone’ (Coen, 2008; Arneson and Arneson, 2013).

As there are so few foods which naturally contain vitamin D, we must rely heavily upon direct sun exposure to meet our bodily requirements. However, there are some foods which contain modest amounts of vitamin D, including oily fish, cod liver oil, milk, yogurt, beef, calf liver, egg yolks, cheese and mushrooms exposed to ultraviolet light to increase vitamin D content.

Testing an individual’s vitamin D status is not only important to identify vitamin D deficiency for the reasons previously highlighted, but as it is fat-soluble, individuals who are not deficient, but supplement anyway, may be at risk of vitamin D toxicity as a result of unnecessary supplementation. The main consequence of this is hypercalcemia, a build-up of calcium in the blood, which can result in nausea, vomiting, fatigue, frequent urination and in extreme cases, kidney problems (Mirrakhimov, 2015). Something else to consider is that not all supplements work successfully and therefore, retesting can also help to ensure that they are being effective, and money is not being wasted.

The CNS Vitamin D Test uses conventional ELISA-based technology to measure serum levels of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 (25(OH)D), which are the most reliable markers of vitamin D status. The technique has been calibrated against the gold standard LC-MS/MS method, demonstrating excellent agreement with external quality assurance. In addition, the CNS laboratory are also active participants in DEQAS (the Vitamin D External Quality Assessment Scheme), which is the largest specialist external quality assessment and accuracy-based scheme for the vitamin D metabolites 25-hydroxyvitamin D2 and 1,25-dihydroxyvitamin D
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A finger-prick blood sample is all that is required, and results are received within 15 working days. This particular diagnostic test is available at the practitioner price of £30.60 and RRP £40.80 (inc. VAT). Click here to order this test