Vitamin D

Vitamin D deficiency has become a hot topic. Last year there were disturbing revelations about the sharp increase in GPs reporting cases of rickets anecdotally in children across the UK, a condition once common in the past that affects bone development.

The importance of vitamin D to our health is becoming more recognised, especially during childhood, to ensure healthy growth, bone and brain development and immunity.

Scientific research shows vitamin D deficiency as a major culprit in the development of disease. Whilst the list is extensive it includes

·      Eczema and asthma

·      Heart disease

·      Diabetes

·      Mood and behavioural problems (depression, schizophrenia, autism, ADHD)

·      Dementia, Alzheimer’s, Parkinson’s

·      Cancer

·      Autoimmune disease such as thyroiditis, multiple sclerosis, coeliac disease, psoriasis

There is a presumption that we should be able to meet all our nutritional needs from a balanced diet. Whilst certain foods do provide some vitamin D value, diet alone doesn’t provide enough, even if we were to eat copious amounts of eggs, oily fish and liver every day. Our main source is ultraviolet radiation from the midday sun absorbed through exposed skin, between April and October, which is when the wavelengths are the right frequency for vitamin D synthesis.

Vitamin D deficiency is much more common than most people realise. A 2007 survey estimated that around 50% of all adults have some degree of vitamin D deficiency. There is an increased risk of Vitamin D deficiency amongst black and minority ethnic communities as darker pigmented skin is less able to absorb sunlight easily, however, everyone in the UK is prone to seasonal fluctuations.

Fears generated by skin cancer warnings have encouraged us to cover our skin, seek shade and coat ourselves in sunblock. Vitamin D synthesis is further thwarted by our modern office-based and indoor lifestyles, and our children may be missing even more essential sunlight hours by staying inside watching television and fixated to computer games.

Whilst the risks of deficiency are considerable, there is often general hesitation to recommend vitamin D supplementation, as there may be a toxic potential to overdosing with an associated risk of increased calcium.

However, the human body can make several thousand units of vitamin D in a matter of minutes in the sun, so if toxicity is a concern, why would nature design us in a way that would make us sick? NHS guidance also tells us that 20-30 minutes of sunlight exposure at midday generates about 2000IU of vitamin D and suggests 2 or 3 sunlight exposures per week during the summer, may provide sufficient vitamin D levels for an individual who has adequate levels to begin with. Unfortunately there is no NHS guidance published yet on what dose of vitamin D supplementation or regimen to use to treat deficiency.

Ideally an individual need for supplementation should be based upon one’s weight, skin colour, frequency of sunlight exposure as well as on blood levels of vitamin D.  So, although cheaper blood tests are becoming more easily available, without testing, a cautious approach to supplementation is recommended.

We now know widespread vitamin D deficiency in the UK is a problem. In mothers and babies it is even more concerning. Pregnancy alone can be a big drain on a mother’s vitamin D levels. That’s why vitamin D supplementation by pregnant, postnatal and breast feeding mothers should be encouraged, not just to replenish body stores but to provide beneficial bone and brain development and immune support to babies.

Optimal vitamin D levels has also been shown to increase human fertility, reduce risk of preeclampsia, increase placental immunity, so reduce any risk of infection to the foetus, and, in a latest study, even reduce the need for pain relief in childbirth.

In France, pregnant women are routinely put on vitamin D supplements but at the moment most pregnant women in the UK are often not given guidance. The most recent guidelines published by the Department of Health suggest that all pregnant and breastfeeding women should take a daily supplement of 400 IU (10 micrograms) of vitamin D. It is important to note that these advisory guidelines are based solely on bone health to ensure development of the foetal skeleton and, as we are learning, the emerging evidence suggests deficiency has other important health consequences.

The easiest way to boost your vitamin D stores is by spending a few minutes each day in the sun between May and September, without sunblock, long enough to synthesise vitamin D without causing skin damage through sunburn. Needless to say consider the strength of the sun and your own sensitivity.

As we approach winter, when skin photosynthesis isn’t an option or if you have found it difficult to get outside in the summer months, you may want to consider supplementation. As daily requirements vary according to age and deficiency levels, without the personal advice of a healthcare professional who will take into account your individual circumstances and risk factors for reduced vitamin D, it is recommended to follow the current UK guidelines that adults take no more than 1,000 IU (25 micrograms) per day. It is also worth noting that vitamin D3, which is the active form of vitamin D, may be more effective than a vitamin D2 supplement.

Current Vitamin D supplementation recommendations by the Department of Health
All pregnant and breastfeeding women 10 micrograms (400 IU) a day
All babies and young children aged six months to five years 7-8.5 micrograms (280-340 IU) of vitamin D a day 
Babies fed more than 500ml infant formula per day Not needed as formula is fortified with vitamin D
Breastfed infants from one month of age May need vitamin D drops if mother has not taken vitamin D supplements throughout pregnancy
People aged 65 years and over 10 micrograms (400 IU) a day
People not exposed to much 10 micrograms (400 IU) a day
You may want to consider taking supplements if: The optimal daily dosage is a matter of continuing debate
your have darker skin Some suggest adults can safely take 20 micrograms (800 IU) per day. Some even suggest 50 micrograms (2,000 IU) would be an optimal dose.
your exposure to sun is limited – e.g. housebound, work nightshifts or live in a high latitude (northern England & Scotland) Current UK guidelines recommend that adults take no more than 25 micrograms (1,000 IU) per day

Article written by Jo Feakes BSc Nut Med mBANT CNHC Registered Nutritional Therapist. Tel:  07801 697 207, email: or visit her webpage at

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