Vitamin D is certainly having its moment right now. In the past few years, research has associated a vitamin D deficiency with higher risks of heart disease, diabetes, cancer, mood disorders and dementia. The world seems to be listening as vitamin D supplements and screening tests have increased in popularity.
Vitamin D is nicknamed the sunshine vitamin as your body produces it when your skin is exposed to the sun. It helps to regulate the amount of calcium and phosphate in the body – nutrients needed to keep bones, teeth and muscles healthy.
While the evidence for vitamin D’s role in bone health is strong, the prevention of other diseases and health conditions is not yet conclusive and need to be researched further.
There’s now also growing interest in whether it could help protect against COVID-19.
Scientists from Queen Mary University of London are launching a new trial to investigate whether vitamin D protects against the virus, as there’s already evidence that it might reduce the risk of respiratory infections, with some recent studies suggesting people with lower vitamin D levels may be more susceptible to coronavirus.
Researchers from Queen Mary, funded by @Barts_Charity, have launched a new clinical trial to investigate whether taking vitamin D could protect people from #COVID19 https://t.co/K1EHuWq2VI pic.twitter.com/kGRtCUJ2L0
— Queen Mary University of London (@QMUL) October 14, 2020
“Vitamin D deficiency is more common in older people, in people who are overweight, and in black and Asian people – all of the groups who are at increased risk of becoming very ill with COVID-19,” says lead researcher Professor Adrian Martineau.
“Making sure you’re getting enough vitamin D is likely to really benefit your bone and muscle health in the long term,” explains nutrition scientist Bridget Benelam from the British Nutrition Foundation (BNF). “Vitamin D is also involved in supporting our immune system, something we’re all really aware of in light of the coronavirus pandemic. No vitamin can prevent or cure COVID-19, but if you’re not getting enough vitamin D, increasing your intake, alongside a healthy diet, can help keep your immune system working as well as possible.”
And dietitian Dr Carrie Ruxton, from the Health & Food Supplements Information Service, notes: “Vitamin D is vital because it contributes to the uptake of calcium by bones and teeth and helps regulate blood levels of calcium and phosphorus.”
So, whatever the outcome of the COVID-19 trial, vitamin D is already known to be beneficial for optimal health. Here are four reasons why it’s important to make sure you get enough vitamin D.
1. Stronger bones
Vitamin D helps regulate the absorption of calcium and phosphorus, so a lack of the vitamin can lead to poor calcification of the skeleton. The BNF explains that prolonged vitamin D deficiency in children leads to rickets, which can cause bone pain, poor growth and bone deformities including bowed legs, curvature of the spine, and thickening of the ankles, wrists and knees, and fractures.
While rickets was for a long time virtually wiped out in the Western world, due to fortification of foods and improved diets, in recent years cases are again being reported. In addition, while osteoporosis in adults isn’t directly caused by vitamin D deficiency, the vitamin can help manage the disease, says the BNF.
2. Stronger muscles
In adults, vitamin D deficiency can lead to osteomalacia, which causes aching bones and muscles plus muscle weakness, which can make standing and walking difficult.
3. Better teeth
Because of its role in regulating the absorption of calcium, vitamin D also helps keep teeth strong, says the BNF.
4. Improved immunity
A 2019 University of Edinburgh study suggests low levels of vitamin D may lead to an increase in immune responses potentially linked to a raised risk of autoimmune conditions, such as multiple sclerosis.
“There are vitamin D receptors on many immune cells,” says Dr Ruxton, “suggesting that it has a widespread role in optimal immunity – an important point as we face a continuation of the COVID-19 crisis, just when the winter flu and cold season approaches.”
People at risk of vitamin D deficiency
If you have little or no sunshine exposure you could be at risk of vitamin D deficiency as it’s difficult to get the daily recommended amount from diet alone. Oily fish and shellfish provide some vitamin D, egg yolks have a small amount, and some dairy products are fortified with it. However, you need to consume 140g of salmon, 200g of halibut or almost a litre of milk to get 400 international units (IU) of vitamin D, which is the lower end of the daily recommended amount.
You may need to look into a daily supplement of vitamin D throughout the year if you:
- are not often outdoors – for example, if you’re frail or housebound
- are in an institution like a care home
- usually wear clothes that cover up most of your skin when outdoors.
Although vitamin D supplements are very safe, taking more than the recommended amount every day can be dangerous in the long run.
Should I take vitamin D2 or D3?
You may have seen both vitamin D2 and D3 at the pharmacy. D2 usually comes from plant sources such as wild mushrooms, it’s also used more in fortified food products as it’s less expensive to produce.
Vitamin D3 mainly comes from animal sources such as oily fish, fatty fish, liver and egg yolks. Your skin also produces D3 when it is exposed to the sun.
But which is best? D2 has been the focus of supplements for more than 80 years and is the form used in prescription preparations but both D2 and D3 are available as over the counter supplements.
A 2008 trial tested a 1000 IU megadose of either D2 or D3, a mix of both, and a placebo on 68 healthy adults aged 18 to 84. Interestingly, 60 per cent of participants were deficient in vitamin D at the start of the trial. At the end of the 11 weeks, D2 and D3 were found to be equally effective at boosting blood levels of vitamin D. So, go for whichever one is available to you, or what your healthcare provider recommends.
How much should I take?
Vitamin D intake is recommended at 400–800 IU per day or 10–20 micrograms.
Have you heard about the benefits of vitamin D before? How do you ensure you get enough? Do you take any supplements?
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Disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.