Vitamins are a major requirement for the body to function properly and, deficiency in a vitamin can be detrimental to health. Most vitamins are present in different types of food; hence, no need to worry about having an insufficient supply but nutritional deficiency of vitamin D is common because most foods contain a little amount of it.

About one-quarter of the UK’s population is deficient in vitamin D and, this number rises to one-third during winter. This is so because the primary source of vitamin D is sunlight. Only a few types of food like oily fish, egg yolk, milk, mushrooms, and cod liver oil contains vitamin D.

Since a deficiency of vitamin D tests in London may notice until some complications arise, it is important to get routine a full blood test in London to check that you have enough vitamin D for your body to function.

Importance of vitamin D

Vitamin D has several functions in the body, which include enhancing the absorption of calcium from the gastrointestinal tract and bone mineralization. The deficiency of vitamin D in adults can lead to osteomalacia. In osteomalacia, the bone is broken down by osteoclasts to increase serum calcium.

There are also claims that vitamin D deficiency can be linked to chronic fatigue syndrome, macular degeneration, reproductive health issues, and various cancers.

Causes and risk factors of vitamin D

Sunlight is pretty vital for the synthesis of vitamin D, but, there are other causes and risk factors. The vitamin D gotten from the sun and food is inactive and has to undergo a lot of conversion in the liver and kidney to form the usable metabolite known as 1, 25- dihydroxy vitamin D. Inactive vitamin D also undergoes renal conversion.

The factors for vitamin D deficiency arises from conversion stages as well as the formation of inactive vitamin D

Risk factor due to reduced intake in the diet or lack of exposure to sunlight

  • Restrictions in the diet (vegans)
  • 65 years and above – the substrate responsible for the synthesis of vitamin D is reduced.
  • Darker skin- the melanin in people with darker skin absorbs some UVB light which makes them require more sunlight to produce vitamin D.
  • Malabsorption in coeliac and post-bariatric surgery
  • Reduced exposure to the sun- those who rarely leave the house or cover the skin when outside

Risk factor due to reduced liver conversion

  • Chronic liver disease
  • Induction of liver enzymes

Risk factor due to reduced renal conversion

  • Nephrotic syndrome
  • Reduced parathyroid hormone
  • Chronic renal failure

Risk factor due to increased demand for vitamin D

  • Pregnancy
  • Breastfeeding

Recommendation for vitamin D supplementation

The Public Health England (PHE) recommends that people in the UK should take 10mcg (400IU) supplement of vitamin D during winter and autumn because sunlight is insufficient during this period. Babies who consume at least 500ml of formula daily do not need Vitamin D supplement because the formula is fortified with vitamin D but babies who are being breastfed need at least 8.5 – 10 mcg supplement of vitamin D.

Those who have only little exposure to sunlight, or those who cover all their skin when outside need to take vitamin D supplements throughout the year. They should get these supplements only from certified places, such as

Test for vitamin D

Most people do not need vitamin D test but, same-day blood tests London for vitamin D should be performed in the following cases for adults over 18 years.

  • Chronic widespread pain
  • Symptoms of hypocalcaemia (e.g. muscle cramps, numbness)
  • Symptoms of osteomalacia (e.g. bone pain, muscle aches and weakness, impaired physical function, waddling gait, symmetric lower back pain)
  • Fall or sprain
  • A bone disease that needs treatment with vitamin D (osteoporosis, Paget’s disease)

Vitamin D test should be performed for children in the following cases

  • Unexplained bony pain or muscular weakness
  • Suspicion of rickets (bow legs, knock knees, delayed tooth eruption, painful wrist swelling)
  • A chronic disease that may increase the risk of vitamin D deficiency

Vitamin D insufficiency

Vitamin D insufficiency and deficiency are often misdiagnosed as there is no clear consensus to differentiate them. However, the National Osteoporosis Society (NOS), NICE, and the Institute of Medicine have agreed on the following as thresholds for determining vitamin D deficiency and insufficiency.

Serum 25 OHD levels (nmol/l) Vitamin D status
<30 Deficient
30 – 50 Insufficient in some people
>50 Sufficient

The risk of developing skeletal problems increases with a vitamin D level less than 25nmol/l.

Treatment for vitamin D deficiency

People with vitamin D deficiency require a loading dose of approximately 300,000 IU of the vitamin, which can be administered in the following ways.

  • 50,000 IU once a week for six weeks
  • 20,000 IU twice a week for seven weeks
  • 4,000 IU daily for ten weeks

Blood test after treatment

Private full blood test London should be carried out a month after treatment to check the level of serum calcium. If hypercalcaemia is discovered, this may be an indication of primary hyperparathyroidism, so the patient would not need to take more vitamin D and, an investigation would be carried to make an accurate diagnosis. The frequency of vitamin D testing after treatment depends on some set guidelines by the NOS and NICE.

Over-the-counter supplements

Some people do not need routine monitoring and can take over-the-counter vitamin D supplements. Those with vitamin D insufficiency who have completed their loading dose would need a maintenance dose of 800 IU per day while, people with malabsorption disorders may need 2000 IU – 4000IU.

Symptoms of vitamin D toxicity

Vitamin D toxicity is rare and, is only seen in people who are taking very high doses of the vitamin over extended period. Symptoms of hypercalcaemia include:

  • Vomiting
  • Nausea
  • Weight loss
  • Headache
  • Altered bowel habit
  • Thirst

Vitamin D toxicity is associated with serum levels of at least 300 – 600 nmol/l. The loading and maintenance dose of vitamin D rarely causes toxicity.

Lifestyle changes

You can optimise your dietary intake of vitamin D and calcium. Exposure to sunlight to get vitamin D is essential, but, excess sunlight is a significant risk factor for melanoma. Sufficient sunlight can be gotten from short periods of exposure to sunlight, especially during the summer periods. Sunscreen is necessary for prolonged exposure to the sun as sunbeds increase the risk of developing melanoma by about 20%.

If you think that you are vitamin D deficient, you can carry out same-day blood tests in London at Blood London. You can call us now on 020 71830244 to book an appointment for your vitamin D blood test.