With autumn vaccination campaigns underway to boost protection against respiratory viruses, it is the perfect time to think about what you could do to stay healthy as winter approaches. Many people are unaware that almost everyone in the UK is recommended to take a simple supplement from now until April. Vitamin D is an essential nutrient that helps to regulate the amount of calcium and phosphate in the body.
Why do we need vitamin D?
Dr Crystal Wyllie, a GP at Asda Online Doctor, explains that having low vitamin D can put you at higher risk of certain bone disorders, such as rickets in children or osteomalacia in adults, a condition which causes the bones to become soft and weak. As well as being crucial for bone and joint health, vitamin D is also important for a healthy immune system.
Dr Wyllie said: “It helps support the cells involved in our immune response, helping the body to regulate how it responds to bacteria and other potential threats.
“Vitamin D also plays a role in keeping our muscles working properly and helps maintain the right levels of calcium in the blood, which is important for keeping our muscles and nerves working properly.
“Your brain and nervous system are another area where vitamin D plays a role. Vitamin D receptors are found throughout the brain, and research suggests it is involved in supporting the development and function of nerve cells.
“There has also been research linking low vitamin D levels with depression, although clinical trials have not proven that taking vitamin D can ease symptoms, so it shouldn’t be viewed as a treatment for depression.”
Can you get enough vitamin D without supplements?
Our bodies can make vitamin D from sunlight but this becomes more difficult during winter, when there are fewer daylight hours and cold weather means people are less likely to venture outside. Most people make enough vitamin D from sunlight between later March and September, but are unlikely to produce enough naturally between October and March.
Dr Wyllie added: “Many people may feel the effects of low vitamin D over this period, such as headaches or feeling ‘bone aches’, but may write it off as Seasonal Affective Disorder (SAD) or fatigue if they haven’t had blood work tests.”
She said: “You can indeed up your vitamin D levels through diet, though when you are not getting the majority of your vitamin D intake from sunlight in the winter periods, it is not enough alone to get sufficient intake.
“For example, you can get vitamin D through red meats, liver, egg yolk and oily fish, or fortified foods such as cereals and spreads. So, a meal such as poached eggs and salmon on toast may be high in vitamin D, but it is not enough alone to satisfy your vitamin D needs over winter.
“In addition to this, if you see American healthcare professionals recommending milk as a form of vitamin D, it is worth considering as well that in the UK, cows' milk is generally not a good source of vitamin D because it is not fortified, as it is in some other countries.”
Claims have circulated on social media platforms that sunbeds and sun lamps can boost vitamin D intake, but Dr Wyllie cautioned against this advice. She explained: “For these forms of synthetic sunlight to give any form of vitamin D to users, they need to include UVB, a type of ultraviolet radiation that causes sunburn and helps the body create vitamin D.
“However, considering that using a sunbed before the age of 35 increases the risk of the most dangerous form of skin cancer by 60%, the potential long-term health implications mean that medical professionals would never recommend using any of the above.
“In terms of lamps, they would need to be medically graded, with most lamps targeted towards SAD not containing UVB rays to stimulate vitamin D production.”
What does the Government recommend?
Guidance from the Department of Health and Social Care advises everyone in the UK to take a daily vitamin D supplement during the autumn and winter months to support general health and in particular for bone and muscle health.
Dr Wyllie said: “In the UK, vitamin D deficiency is especially common, particularly over the autumn and winter periods. In fact, it is recommended by the NHS that everyone in the UK takes an over-the-counter supplement containing 10 micrograms (400 IU) daily from October to April.
“If you spend a lot of time indoors, cover up when outside, have darker skin, or wear high-factor sunscreen, you have a greater risk of deficiency and should take a supplement throughout the year.”
Dr Wyllie added that vitamin D is absorbed better when taken alongside a meal containing some fat. She said: “If you’re taking a tablet, in order for it to be absorbed by your body, you would need to take it with a meal or snack containing a fat source. Something as simple as having it alongside breakfast with eggs, avocado or full-fat yoghurt can help.”
Can you take too much vitamin D?
Vitamin D tablets are generally safe for adults and children when taken at the recommended dose. Dr Wyllie said: “Adults should not take more than 100 micrograms (4,000 IU) of vitamin D a day, as this could be harmful.
“Children aged one to ten years should not have more than 50 micrograms (2,000 IU) a day, while infants under 12 months should not have more than 25 micrograms (1,000 IU) a day. This applies to adults, including pregnant and breastfeeding women and the elderly, as well as children aged 11 to 17.
“It’s important not to assume that because something is a vitamin, taking more of it is better. Very high levels of vitamin D in your blood can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, excessive urination and thirst, and kidney stones.
“Extremely high levels of vitamin D can cause kidney failure, an irregular heartbeat, and, in very severe cases, can even be life-threatening.
“You cannot get too much vitamin D from sunshine because your skin naturally limits the amount of vitamin D it makes. High levels of vitamin D are almost always caused by consuming excessive amounts through dietary supplements, which is why it’s important to stick to the recommended dose.
“It’s also worth checking the labels of any other supplements you are taking, as vitamin D can be included in multivitamins and other products. It can be easy to accidentally take more than you realise if you are taking several supplements at once.”
