Vitamin D is an essential fat-soluble vitamin important for our bones and deficiency affects nearly every system of our body. It is unique as much of it comes from sunlight and there are only small amounts in our food.
60% of UK population have insufficient Vitamin D
There has been an alarming rise in Vitamin D deficiency, particularly in children where rates of deficiency were 15 times higher in 2014 than in 2000 (1). This might be due to increased testing as it becomes clearer how important Vitamin D is. It may also be due to spending less time outdoors and the increased use of sunscreen.
Children, elderly people (particularly those in care homes) and those with darker skin tones are particularly at risk (2).
90% of Vitamin D is from sunlight
To raise blood Vitamin D levels to over 50nmol/L (bare minimum for good health) white British people require 13 minutes of skin exposure to midday summer sun at least three times a week (2). Two of the highest sources only just provide the minimum adult RDA. It takes 100g of cooked Sockeye salmon to provide 526IU (13.1μcg) and a whole can of tuna contains only 154IU (3.9μcg). The exception is cod liver oil which provides 1360IU (13.1μcg) per tablespoon (3).
For 6 months of the year UK daylight doesn’t give us enough Vitamin D
During winter months in the UK there is not enough UVB light for vitamin D synthesis (2) and we have to use any vitamin D stores from the summer or from supplements. The NHS now recommend that everybody considers taking a vitamin D supplement, particularly children, over 65’s, those with darker skin tones, pregnant women and breast-fed babies (4).
Low levels can cause bone problems
Vitamin D is needed along with Calcium, Magnesium and Vitamin K2 for healthy mineralisation of our bones. It is also needed for bone growth and health, and to prevent and help fractures (5). Vitamin D deficiency can cause rickets in children and osteomalacia in adults. Vitamin D helps protect adults from osteoporosis (6).
Vitamin D deficiency can cause increased infections
Vitamin D deficiency not only increases your risk of catching an infection it also increases your chance of that infection being more serious (including sepsis) and also your chance of dying from it (7).
Deficiency can cause pain and muscle weakness
Vitamin D helps to maintain muscle mass and strength as well as bone strength (8). Small studies have shown Vitamin D supplements can improve musculoskeletal pain (9) and osteoarthritis knee pain (10).
Deficiency can lead to poor growth and seizures in children
Vitamin D deficiency can cause hypocalcemic tetany (low calcium from low Vitamin D) leading to seizures (11). It is also linked to growth problems, heart problems, autoimmune disease and ADHD in children (12).
Vitamin D supplements may help mood
Many people feel their mood drop during the darkest months of winter, this is a good time to consider a Vitamin D supplement. Low Vitamin D levels have been found to increase the risk of depression and anxiety (13) and supplements may improve depression symptoms (14).
Vitamin D is critical to the immune system
Immune system cells have specific receptors for Vitamin D and are capable of activating it, showing how important this vitamin is to our immune system. Vitamin D helps maintain a healthy immune system, protect against infection and autoimmune diseases, and regulates cell growth. It could also protect against cancer (15). More recently research suggests low Vitamin D levels may contribute to food allergies (16), possibly through its role in gut health.
Vitamin D is important for memory & brain function
Vitamin D can protect against Alzheimers and Dementia, and is important for our brain function and memory (17).
Vitamin D has a role in gut & heart health
Vitamin D helps reduce inflammation in the gut and is important in reducing the risk of inflammatory bowel diseases like Crohn’s (18). Vitamin D helps support heart health, lower high blood pressure and reduce atherosclerosis (19) (although it should be taken with Vitamin K2 to prevent this).
Get your levels checked
Dr Jess says: I recommend all UK adult patients* take a Vitamin D supplement between the clock changes (October and March) of 2000-4000IU (50-100μcg), preferably with Vitamin K2. I suggest you have your levels checked by blood test if you have any health conditions which could benefit from Vitamin D or darker skin tone. If you are an indoor worker or wear high factor sunscreen you could consider taking the supplement all year round as our family does.
Children should take at least 20μg (800IU) and consider up to 100μg (4000IU) after age 9. The benefits of optimum Vitamin D levels are now indisputable, it is definitely in the top 3 of my supplements for patients. Many doctors believe we should aim for blood test levels of 70nmol/L for optimum health (rather than the minimum 50nmol/L recommended by the NHS).
*Do not take Vitamin D without talking to your healthcare provider if you have high Vitamin D levels, primary hyperparthyroidism, hypercalcaemia, tuberculosis, sarcoidosis, or are in kidney failure.
HOW DO YOU GET MORE VITAMIN D?
Go outside! – Modern life makes us more and more likely to stay indoors, but the benefits of being outdoors are incredible! As well as being the best way to get Vitamin D, sunshine itself promotes lower blood pressure and heart rate, the air quality is better and even the trees around us can reduce stress (read more about reducing stress and forest bathing here).
Eat oily fish – Tuna, mackerel and salmon are good sources of Vitamin D.
Organic raw milk – Is a great source of Vitamin D – choose a good supplier.
Organic egg yolks – Are a great part of any real food diet, and a good source of Vitamin D.
Take a Vitamin D supplement – Get your levels checked with your healthcare provider if unsure (aim for 70nmol/L) but generally a maintenance dose of 800i.u(10-20μg) daily for children and 2000-4000i.u. (50-100μg) daily for adults is safe and beneficial.
Consider a SAD lamp – Although they don’t raise Vitamin D, by mimicking better light levels many people report increased mood and energy levels using a special SAD lamp to combat shift work and short daylight hours in the winter.