Are you D-ficient? (Why we need vitamin D)
At this time of year – and in the midst of the pandemic – we all need to think about our levels of vitamin D. We know vitamin D as the ‘sunshine vitamin’, and that our bodies manufacture it after exposure to sunlight – the only vitamin that we don’t get solely from food. Vitamin D helps to regulate levels of calcium and phosphate in our bodies, which is needed for healthy bones, teeth and muscles.
Where we get vitamin D from
It’s tricky to get enough from food. Good sources include oily fish (salmon, mackerel, herring and sardines), and egg yolks. Some foods are fortified with vitamin D, including breakfast cereals, fat spreads and non-dairy milk alternatives like soya or oat. You can buy mushrooms rich in vitamin D, marketed by UK & Ireland Mushroom Producers; or up levels yourself by exposing mushrooms to strong sunlight.
Why we may need more vitamin D
Around one in five people in the UK have low vitamin D levels. Deficiency symptoms may include muscle pain and weakness, risk of fractures and osteomalacia (bone softening). In children, severe deficiency results in rickets, where the bones of the leg are deformed, causing them to bow outwards. This was virtually eradicated in the UK in the 1950s, but child food poverty is causing it to make a comeback.
In spring and summer, most people in the UK can generate enough vitamin D from being in the sun daily for short periods with forearms, hands or calves uncovered and without sunscreen, especially from 11am to 3pm. How much time in the sun is enough, depends on the strength of the sun and how much skin you’re showing.
But from October to March, the sun isn’t strong enough for our bodies to make it, so many of us risk deficiency. The NHS currently advises everyone to take a daily supplement of 10 micrograms (or 40 International Units, IU) through these months. Most good-quality vitamin and mineral supplements contain this amount – check the label.
Levels can be lower than normal in many people, including those who are overweight, and black and minority ethnic people, who might want to take a supplement year-round.
As we age, our skin gets thinner, which means it’s less able to synthesise vitamin D. During the first five years of menopause, we can lose nearly 10% of muscle mass, so getting enough vitamin D is crucial.
If you’re on statins to lower cholesterol you may be aware of the commonly reported side-effect of muscle pain. There has been some debate on whether these pains are actually a sign of vitamin D deficiency, since cholesterol is needed for the vitamin’s synthesis in the body.
I decided to test my own vitamin D levels because writing this sparked my curiosity– and it would be silly to write about possible deficiency while unknowingly suffering it. As an overweight vegetarian, I’m at slightly higher risk, because I’m overweight and because many D-rich foods are of animal origin.
Current National Institute for Health and Care Excellence guidelines say health professionals shouldn’t test vitamin D levels unless there are symptoms of deficiency, so I tried BetterYou’s test kit, £32.95, including DLux Vitamin D Oral Spray at the right strength for your level (sent after testing). It arrived in a letterbox-fitting cardboard box, with comprehensive instructions on how to take a blood sample and drop four drops on the little card, an alcohol wipe and even a plaster. Because I am a wimp, I had to screw up my courage to stab my finger with the little spring-loaded lancet device. This punctured me perfectly, albeit a bit more painfully than a blood test by someone else. The results arrived within 10 days and I was relieved to see that I had the top status: ‘adequate’, above the levels ‘severe deficiency’, ‘deficiency’ and ‘insufficiency’.
Superdrug also sells a test for £36.
Covid and vitamin D
Another reason to take that supplement is because people with low vitamin D levels might be more at risk of catching Covid-19. Queen Mary University of London is currently carrying out a six-month home-based study of over 5,000 people on the effects of vitamin D supplementation.
Lead researcher Professor Adrian Martineau said: ‘There is mounting evidence that vitamin D might reduce the risk of respiratory infections, with some recent studies suggesting that people with lower vitamin D levels may be more susceptible to coronavirus. Vitamin D deficiency is more common in all of the groups who are at increased risk of becoming very ill with Covid-19.’
Principal investigator, Dr David Jolliffe, added: ‘The trial has the potential to give a definitive answer to the question of whether vitamin D offers protection against Covid-19. Vitamin D supplements are low in cost, low in risk and widely accessible; if proven effective, they could significantly aid in our global fight against the virus.’
Adrienne Wyper is a health and lifestyle writer and regular TNMA contributor.