Thursday August 11, 2016
Vitamin D - The Sunshine Vitamin
Why vitamin D?
We have all heard that vitamin D is good for our bones. However, few of us really understand how seriously a lack of vitamin D can impact our day to day wellbeing. In fact, one UK survey found that more than half of us are vitamin D deficient!
Why does this matter?
Well, Vitamin D’s job is to regulate the level of calcium and phosphate in the body. It does this by controlling how much is absorbed in the gut and taken up by the different parts of the body, including muscle, teeth and bone. As a result, Vitamin D deficiency causes muscle weakness, tiredness and bone pain. In extreme cases, a lack of vitamin D can impair bone growth causing diseases of brittle or painful bones, such as Rickets in children and osteomalacia in adults.
Where does our vitamin D come from?
Most of our vitamin D is produced in our skin. Sunlight plays a key role in activating the vitamin D, hence its nickname “the sunshine vitamin”. Unfortunately, winter sun is not great at making vitamin D (it does not contain enough ultraviolet B radiation) and sunlight through a window does not work either. The best way to get vitamin D from the sun is to exposure our skin to the summer sun. If you are spending a lot of time in the sun, remember to take the necessary precautions to protect your skin from sun damage!
We can also get vitamin D from oily fish (mackerel, herring, salmon, sardines), red meat, eggs and certain foods (breakfast cereals, formula milk) have added vitamin D.
Who gets vitamin D deficiency?
Infants under 1 year of age need 8.5 to 10 micrograms of vitamin D a day and the rest of us need 10 micrograms a day. Most of the population can make a lot of vitamin D from the sunlight we get in the Spring and Summer months.
However, there are certain groups of people who are at a higher risk of vitamin D deficiency:
- The elderly (skin thins as we age, reducing its ability to make vitamin D)
- People with darker skin (dark skin needs more sunlight to make the same amount of vitamin D as paler skin)
- People with reduced skin exposure to sunlight (such as those who spend a lot of time indoors or those who cover a large proportion of their body)
- Pregnant or breastfeeding women
- People with certain diseases (such as Crohn’s disease, coeliac disease, kidney disease)
- People taking certain medications (such as carbamazepine, phenytoin, primidone)
- People on strict vegetarian or vegan diets
And sometimes, for unknown reasons, people without any risk factors are deficient in vitamin D! These can be evaluated along with any other Vitamin Deficiency by a GP.
Vitamin D supplements
Vitamin D supplements are available in most pharmacies and supermarkets. For adults, vitamin D supplements typically take the form of 10 microgram tablets called colecalciferol or ergocalciferol, while “vitamin drops” are available for children under 5.
Vitamin D supplements may be prescribed by doctors for people who have a higher risk of vitamin D deficiency. For example, UK health departments recommend that:
- All pregnant and breastfeeding women should take a daily supplement containing 10µg of vitamin D, to ensure the mother’s requirements for vitamin D are met and to build adequate fetal stores for early infancy.
- All infants and young children aged 6 months to 5 years should take a daily supplement containing vitamin D in the form of vitamin drops, to help them meet the requirement set for this age group of 7-8.5 micrograms of vitamin D per day. However, those infants who are fed infant formula will not need vitamin drops until they are receiving less than 500ml of infant formula a day, as these products are fortified with vitamin D. Breastfed infants may need to receive drops containing vitamin D from one month of age if their mother has not taken vitamin D supplements throughout pregnancy
- People aged 65 years and over and people who are not exposed to much sun should also take a daily supplement containing 10 micrograms of vitamin D.
What happens if I have too much vitamin D?
While it is not possible to get too much vitamin D from sunlight, very high doses of vitamin D supplements can cause the calcium levels in the blood to be too high. This can cause symptoms of nausea and vomiting, headaches, thirst and passing a lot of urine. If you are taking vitamin D supplements and experience these symptoms, then we recommend you speak to your GP as soon as possible!
Do I need vitamin D supplements?
If you think you may be at risk of vitamin D deficiency, why not book an appointment at any of our six central London Clinics? Our GPs are more than happy to have a chat with you and we can even organise a blood test to measure the levels of vitamin D in your body.