For years, it has been widely accepted by scientists that vitamin D deficiency is a longstanding health problem, with implications on health and wellbeing. While there are a wealth of reasons for vitamin D deficiently, inadequate skin synthesis due to restricted sunlight, limited food fortification and lack of vitamin D from natural food sources are confirmed contributing factors.

Here, we discuss how certain health conditions can further enhance the risk of vitamin D deficiency and ways to increase its consumption.

The levels of vitamin D deficiency

In the UK, currently, Reference Nutrient Intakes (RNI) for vitamin D are only set for children aged 1.5-3 and adults over 65 years of age. Using the average intakes for each of these age groups, data from the latest UK National Diet and Nutrition Survey (NDNS) revealed that intakes of vitamin D from food sources are just 27% of the RNI for children and 33% for adults, showing significantly low vitamin D levels from food sources.

When it comes to assessing blood biomarkers in relation to vitamin D levels, plasma vitamin D levels of <25 nmol/L are used to identify a deficiency. Using this as an indicator, it was revealed that on average, 19.7% of boys and 24.4% of girls aged 4 to 10 had levels less than 25 nmol/L, while 24% of men and 21.7% of women aged 19 to 64 has plasma vitamin D levels below this.

The survey also revealed that when averaged out across the year, 40% of young people and adults were deficient between the months of January and March.

Health conditions which can increase the risk of vitamin D deficiency

Malabsorption, coeliac disease, cystic fibrosis, short bowel syndrome and inflammatory bowel disease (IBD) can all increase the risk of vitamin D deficiency.

Amongst adults, an Irish study involving 81 patients with Crohn’s disease (CD) revealed that 63% were vitamin D deficient. Furthermore, a study of patients with coeliac disease in the US showed that 25% had vitamin D deficiency.

Common signs of deficiency

When it comes to symptoms of vitamin D deficiency, these tend to vary across the lifespan and with the level of deficiency. During adolescence, symptoms typical of severe deficiency include muscle cramps, pain in weight-bearing joints and problems walking, running or climbing stairs. In adults, a mild lack of vitamin D may present itself as general aches and pain, while more severe deficiency is associated with osteomalacia and post-menopausal increased fracture risk. Furthermore, suboptimal vitamin D levels are associated with an increased risk of severe infections and sepsis amongst those that re critically ill.

Vitamin D supplements

When it comes to supplementing vitamin D levels, we must first ascertain whether it is to maintain and prevent deficiency or to treat a diagnosed deficiency. In the care of maintaining levels, The European Food Safety Authority (EFSA) proposed an adequate intake of 15 µg/day for adults. In the UK, while RNIs are not available, it has been suggested that 10 µg/day for those aged 11 to 65 is suitable.

In the situation of vitamin D deficiency, such as in cases of patients with diagnosed bone diseases, it has been advised by the National Osteoporosis Society that levels are increased rapidly with doses of up to 7500 µg. So, for example, taking 20 µg/day capsules, five times a day for 10 weeks could be used to rapidly correct low levels, and following this, levels should be maintained. When it comes to which form of vitamin D supplementation to take, evidence suggests that vitamin D3 (cholecalciferol) is effective at raising levels.

Here at 121 Dietitian we support all the evidence regarding Vitamin D deficiency and the importance of correcting low levels. However the safety of increasing levels and continued maintenance of these levels are of concern, and so we prefer to guide our patients with a safe combination of a whole food diet rich in Vitamin D foods and natural supplementation of key nutrients.

Why?

Many of the general population are correctly taking action and looking after their own health, and over the counter supplementation has been around for a long time, nothing new there. The issue is the toxic levels of Vitamin D supplementation that people are taking and the length of time they are taking them for with no monitoring.

Hypervitaminosis D is a rare but potentially serious condition. It occurs when you take in too much vitamin D. It’s usually the result of taking high-dose vitamin D supplements without checking your status.

Too much vitamin D can cause abnormally high levels of calcium in the blood. This can affect bones, tissues, and other organs. It can lead to high blood pressure, bone loss, and kidney damage without treatment.

Vitamin D can also affect Vitamin A, Vitamin K and magnesium levels and if the ratio is not maintained then you may experience further unpleasant side effects.

As of the past number of years GP’s in Northern Ireland are unable to routinely measure peoples Vitamin D levels.  This for me as a health professional is disappointing and worrying as we are frequently seeing cases of severe deficiency and many with long term excessive use and negative consequences. Monitoring needs to happen.

In summary, Vitamin D deficiency is common in the UK, particularly during the winter months and notably in vulnerable populations. While symptoms can be hard to spot, tiredness and general fatigue are common and may suggest your levels should be assessed by your GP or through a simple blood test where possible. Action should be taken based on these findings and current health status.

If you are unsure of how to change your eating habits, or need help optimising the foods you eat please do contact us. We would love to help you or your family and friends with any nutrition related queries big or small.

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Information checked & correct on 16th May 2018 and updated Jan 2021.