Should I be taking a vitamin D supplement?

The COVID-19 pandemic has left a lot of us spending more time indoors than we normally would and for high risk individuals and the elderly the guidelines are to self isolate for 3 months meaning no time at all can be spent outside. Due to the fact that vitamin D is converted to its active form by the action of sunlight on the skin there is an increased risk of widespread vitamin D deficiency. 

Vitamin D is essential to keeping your body healthy. Not only is it good for bones and teeth, but research has shown that it also plays a role in the immune system. In fact, a study undertaken fairly recently by Trinity College Dublin found that adults who took vitamin D supplements saw a 50% fall in chest infections.

We can obtain vitamin D from food sources such as eggs and oily fish as well as fortified foods but it is extremely difficult to get enough through diet alone, the primary source is via skin's exposure to the sun. This is why government health advice recommends we consider taking a daily supplement especially during winter months and those that fall within vunerable groups of the population are strongly advised to supplement with 10 micrograms every day through the year.  Vulnerable groups are at greatest risk of inadequate vitamin D status and include children aged 1-4 years, people who don’t often go outdoors such as the frail or housebound, those in care homes, or people who usually cover their skin when going outdoors and those with darker skin. 

The recent Health of the Nation survey carried out by the HFMA revealed that under a third (31%) of people living in Britain were aware of the Public Health England (PHE) recommendations that all adults and children over the age of five years should consider taking a vitamin D supplement throughout the winter months. This lack of awareness causes concern that some people may be low in vitamin D and will particularly need to top up their levels up over the coming months while we are all spending more time indoors. 

The HFMA have recently issued a statement on ways to maintain optimum vitamin D status this spring in which they said:

In March to September, longer daylight hours mean that the skin has more opportunity to synthesise vitamin D. So, with the UK’s current situation, it is important that we all take advantage of sunny days to get out in the garden and for regular exercise when we can. Exposing the forearms, hands or lower legs to the sun, without sunscreen, for a short time between 11am and 3pm will help keep vitamin D status topped up. For people who don’t have access to their own outside space, going out once a day for a walk or run, or some other form of regular exercise is particularly important.

What are the symptoms of a Vitamin D deficiency?

• tiredness, aches and pains, and a general sense of not feeling well
• increased incidence of sickness and viral infections
• depression
• impaired wound healing
• severe bone or muscle pain or weakness that may cause difficulty climbing stairs or getting up from the floor or a low chair, or cause you to walk with a waddling gait
• stress fractures, especially in your legs, pelvis, and hips  

Can you take too much vitamin D?

Vitamin D sourced from sunshine and food cannot lead to an overdose within the body. This is because sustained heat on the skin is thought to photodegrade previtamin D3 and vitamin D3 as it is formed. Additionally, thermal activation of previtamin D3 in the skin gives rise to various non-vitamin D forms that limit formation of vitamin D3 itself. 

However Vitamin D toxicity (also known as hypervitaminosis D) can occur when a person has too many vitamin D supplements. Taking too many supplements over a long period of time can cause too much calcium in the body to build up which can lead to weakness of the bones and damage to the kidneys and heart.

The current recommended daily allowance of vitamin D in the UK is currently 400IU but larger doses can be taken for a short time to rectify a deficiency.