As summer comes to an end and autumn arrives, the days become shorter, temperatures drop and we naturally spend more time indoors. That change in season can also affect how we get vitamin D.
Vitamin D is often called the “sunshine vitamin” because our bodies can produce it when our skin is exposed to sunlight. However, in the UK, there are times of year when sunlight isn't strong enough for the body to make sufficient vitamin D from sunlight alone. ¹
Vitamin D contributes to normal immune system function, normal muscle function and the maintenance of normal bones and teeth. ² So, as autumn approaches, it's a good time to think about your vitamin D intake and whether a supplement could form part of your daily routine.
In this guide, we'll explain why vitamin D becomes particularly important during autumn and winter, how your body gets vitamin D, which foods contain it and what to know about vitamin D supplements.
What Is Vitamin D?
Vitamin D is a fat-soluble vitamin that plays several important roles in the body.
It contributes to:
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The normal function of the immune system
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Maintenance of normal bones
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Maintenance of normal teeth
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Normal muscle function
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Normal absorption and utilisation of calcium and phosphorus
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Normal blood calcium levels
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The process of cell division ²
Vitamin D is different from many other vitamins because our bodies can produce it naturally when our skin is exposed to sunlight.
This is why sunlight is such an important source of vitamin D.
Why Is Vitamin D Important in Autumn?
During the spring and summer months, sunlight exposure can provide our bodies with vitamin D.
However, as autumn arrives, the days become shorter and the sun sits lower in the sky. In the UK, there is also a period during the autumn and winter months when sunlight doesn't contain enough UVB radiation for our skin to make vitamin D effectively. ¹
This means that even if you spend time outside during autumn, your body may not be able to produce vitamin D from sunlight in the same way it can during the summer. This is one of the reasons why vitamin D supplements are particularly relevant during the colder months.
When Should You Start Taking Vitamin D?
The UK government recommends that everyone consider taking a daily vitamin D supplement during the autumn and winter months because it is difficult to get enough vitamin D from sunlight during this time of year. ¹
The NHS recommends a daily supplement containing 10 micrograms (400 IU) of vitamin D during autumn and winter. ¹
Some people are advised to take vitamin D throughout the year, including those who have little or no exposure to the sun, people who usually cover most of their skin when outdoors and people from certain ethnic minority groups with darker skin. ¹
If you're unsure whether you should take vitamin D all year round, speak to a healthcare professional.
Can You Get Vitamin D From Sunlight in Autumn?
It depends on where you live and the time of year. In the UK, sunlight is generally a useful source of vitamin D during the spring and summer months. However, between roughly October and early March, sunlight doesn't contain enough UVB radiation for our skin to make vitamin D effectively. ¹
This means that simply spending more time outdoors during the UK winter won't necessarily provide your body with the vitamin D it needs. Getting outside is still important for plenty of other reasons, including physical activity and general wellbeing, but it shouldn't be relied upon as a source of vitamin D throughout the UK autumn and winter.
What Foods Contain Vitamin D?
Unlike some vitamins, there aren't many foods that naturally contain significant amounts of vitamin D.
Sources include:
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Oily fish such as salmon, sardines and mackerel
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Egg yolks
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Red meat
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Liver
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Fortified foods
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Some mushrooms
Oily fish can be a particularly useful dietary source of vitamin D. However, it can still be difficult to get enough vitamin D from food alone, particularly during the autumn and winter months. ¹ This is why supplementation can be useful for many people.
Vitamin D and the Immune System
Autumn and winter are often associated with seasonal illnesses, which makes immune health a common consideration at this time of year. Vitamin D contributes to the normal function of the immune system. ²
This doesn't mean that taking vitamin D will prevent colds, flu or other infections. Instead, maintaining an adequate intake of vitamin D helps support the normal functioning of the immune system as part of a balanced diet and healthy lifestyle.
Vitamin D and Bone Health
Vitamin D is particularly important for maintaining healthy bones because it contributes to the normal absorption and utilisation of calcium and phosphorus. ²
It also contributes directly to the maintenance of normal bones and teeth.
Calcium and vitamin D therefore work closely together as part of normal bone health.
Good dietary sources of calcium include:
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Milk
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Cheese
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Yoghurt
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Fortified plant-based alternatives
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Leafy green vegetables
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Calcium-set tofu
A balanced diet containing a variety of nutrients is important for maintaining healthy bones throughout life.
Vitamin D and Muscle Function
Vitamin D also contributes to normal muscle function. ² This is one reason why maintaining adequate vitamin D intake is important beyond simply thinking about bones and immunity.
Combined with regular physical activity and a balanced diet, getting enough vitamin D can form part of a healthy approach to maintaining normal muscle function.
Who May Be at Risk of Low Vitamin D?
Some people are more likely to have low vitamin D levels. According to the NHS, this can include people who:
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Spend little time outdoors
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Live in a care home or institution
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Usually wear clothing that covers most of their skin when outdoors
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Have darker skin ²
People in these groups may be advised to take vitamin D throughout the year. Older adults may also be at greater risk because their skin becomes less efficient at producing vitamin D from sunlight as they age. ¹
If you're concerned about your vitamin D levels, speak to your GP or another healthcare professional.
Vitamin D for People Who Spend a Lot of Time Indoors
Modern lifestyles mean that many people spend a significant proportion of their day indoors. Working from home, office-based jobs, studying and spending evenings indoors can all reduce the amount of time you naturally spend outside.
During autumn and winter, this becomes particularly relevant because there is already less sunlight available for vitamin D production. This is another reason why checking your vitamin D intake can be a useful part of your autumn health routine.
Should You Take Vitamin D in Autumn?
For most people in the UK, the NHS recommends considering a daily vitamin D supplement during autumn and winter. ¹ The recommended daily supplement is 10 micrograms (400 IU).
Vitamin D supplements are available in different strengths, so always check the label and follow the recommended serving. Taking more isn't necessarily better, and you shouldn't routinely exceed the recommended amount unless advised to do so by a healthcare professional.
What Is Vitamin D3?
There are different forms of vitamin D used in supplements, with vitamin D3 (cholecalciferol) being one of the most common. Vitamin D3 is also the form produced in the skin following exposure to sunlight.
When choosing a vitamin D supplement, check the form and amount provided per serving. For everyday supplementation, it's particularly useful to look at the amount of vitamin D in micrograms (µg) rather than focusing only on the number of tablets or capsules.
How Much Vitamin D Do You Need?
The UK government recommends that adults consider taking a daily supplement containing 10 micrograms of vitamin D during autumn and winter. ¹ The NHS states that adults should not take more than 100 micrograms (4,000 IU) of vitamin D a day unless advised to do so by a doctor. ²
Some people with diagnosed vitamin D deficiency may be prescribed a different dose by a healthcare professional. Always follow the instructions provided with your supplement.
Is Vitamin D Safe?
Vitamin D is an important nutrient, but taking excessive amounts can be harmful. Because vitamin D is fat-soluble, it can accumulate in the body when taken in excessive amounts over a long period.
For this reason, don't take more than the recommended amount unless you've been advised to do so by a healthcare professional. ² If you're already taking a multivitamin or other supplements, check the ingredients to make sure you're not unintentionally taking vitamin D from several different products.
Vitamin D and Your Autumn Routine
Autumn is a good opportunity to reassess your everyday health routine. As the weather gets colder and the days become shorter, try to focus on the basics:
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Eat a varied, balanced diet
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Stay physically active
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Get outside during daylight hours
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Prioritise sleep
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Stay hydrated
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Consider your vitamin D intake
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Take supplements consistently where appropriate
Vitamin D is just one part of a healthy lifestyle, but maintaining an adequate intake becomes particularly relevant during the UK autumn and winter.
Vitamin D and Other Supplements
Vitamin D is often included in combination supplements alongside other vitamins and minerals. For example, magnesium and vitamin D can both contribute to normal muscle function, while vitamin D also contributes to normal calcium absorption and bone health. ²
This doesn't mean that everyone needs to take multiple supplements, your supplement routine should be based on your diet, lifestyle and individual nutritional needs. If you're new to vitamins and aren't sure where to start, it's generally better to focus on the nutrients that are relevant to your diet and lifestyle rather than taking lots of supplements unnecessarily.
FAQs
Should I take vitamin D in autumn?
Yes. The NHS recommends that people consider taking a daily vitamin D supplement during autumn and winter because there isn't enough sunlight during this period for the body to make sufficient vitamin D. ¹
How much vitamin D should I take in autumn?
The NHS recommends a daily supplement containing 10 micrograms (400 IU) of vitamin D during autumn and winter. ¹
Can you get vitamin D from the sun in autumn?
In the UK, sunlight generally isn't strong enough from around October to early March for the skin to produce sufficient vitamin D. ¹
What foods are high in vitamin D?
Oily fish, egg yolks, red meat and liver contain vitamin D. Some foods, including certain cereals and plant-based alternatives, may also be fortified with vitamin D.
What is vitamin D3?
Vitamin D3, also known as cholecalciferol, is a form of vitamin D commonly used in supplements. It is also the form of vitamin D produced naturally by the skin in response to sunlight.
Does vitamin D support the immune system?
Yes. Vitamin D contributes to the normal function of the immune system.² However, this doesn't mean that vitamin D supplements prevent infections.
Does vitamin D help bones?
Vitamin D contributes to the maintenance of normal bones and teeth and to the normal absorption and utilisation of calcium and phosphorus. ²
Who should take vitamin D all year round?
Some people are advised to take vitamin D throughout the year, including those who spend little time outdoors, people who cover most of their skin when outdoors and people with darker skin. ¹
Can you take vitamin D every day?
Vitamin D can be taken daily when used according to the recommended serving. The NHS advises adults not to take more than 100 micrograms (4,000 IU) per day unless advised otherwise by a doctor. ²
Make Vitamin D Part of Your Autumn Routine
As summer turns to autumn, it's worth thinking about how your routine changes along with the seasons. Shorter days and reduced sunlight mean that your body can't rely on sunlight alone for vitamin D during the UK autumn and winter. ¹
A varied diet can provide some vitamin D, but supplementation is recommended for many people during this time of year. Vitamin D contributes to normal immune system function, muscle function and the maintenance of normal bones and teeth, making it an important nutrient to consider as part of your everyday autumn and winter routine.
Small, consistent habits, from staying active and eating well to taking your vitamin D supplement, can help you look after your health as the seasons change.
