Do we still need Vitamin D in the summer? Doctor warns the biggest mistake you've been making
Vitamin D helps regulate the amount of calcium and phosphate in the body – these are essential nutrients that are needed to keep bones, teeth and muscles healthy. As well as through our diet, you can get vitamin D from sunlight, as our skin synthesizes vitamin D when exposed to UVB radiation from the sun.
Government advice in the UK is that everyone should consider taking a daily vitamin D supplement the autumn and winter, due to the decline in sunshine hours, but experts are warning that it’s a risk to stop.
Health coach Kathryn Danzey, and founder of brandRejuvenated says, ‘Often referred to as the ‘sunshine vitamin,’ Vitamin D is produced naturally by the body when the skin is exposed to sunlight.
‘Vitamin D deficiencies are common for those who have limited sun exposure, or who live in northern climates such as the UK. As we get older, our skin becomes less efficient at synthesizing Vitamin D, while individuals with darker skin tones are also at risk, as melanin reduces natural vitamin D production.’
Zoe Hetherington, Nutrition Consultant and Naturopathic Nutritional Therapist at W-Wellness explains that Vitamin D is essential for bone health, immune function, mood regulation, and even hormone balance. ‘It helps the body absorb calcium and phosphorus which are two key minerals for strong bones and teeth. Low levels have been linked to fatigue, low mood, weakened immunity, infertility, and an increased risk of osteoporosis.
‘Vitamin D is unique because we produce it through our skin in response to sunlight but in the UK, this is only possible during certain months. Between late March and early September, we can theoretically make enough, if we spend adequate time outdoors daily, with some skin exposed, in direct sunshine and without sunscreen. That’s a big if.
‘Even in summer, factors like limited sunshine, cloud cover, pollution, skin tone, age, and time spent indoors or covered up can significantly reduce our natural vitamin D synthesis.
‘Sunscreen is crucial for protecting the skin from harmful UV rays and reducing the risk of skin cancer, but it also blocks the UVB rays needed for vitamin D production. That doesn’t mean you should skip the SPF, rather it highlights how tricky it can be to get enough vitamin D naturally, especially if you’re diligent about sun safety.’
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Zoe explains that while Public Health England recommends that everyone in the UK consider taking a daily vitamin D supplement, especially from October to March, even in summer, supplementation is often still a sensible insurance policy.
‘This is particularly important for those who spend most of their time indoors, have darker skin, cover up for cultural or health reasons, or consistently wear high-SPF sunscreen,’ she explains.
‘I recommend Bare Biology Beam & Balance, a high-quality, well-absorbed vitamin D spray with added K2. It allows for easy, flexible dosing throughout the year, making it ideal for adjusting between seasons. For those taking medications that may interact with vitamin K2, such as blood thinners, Wild Nutrition Food-Grown® Vitamin D is an excellent alternative. Delivered in capsule form, it provides a highly absorbable source of vitamin D without the inclusion of K2.’
Why do we need vitamin D?
A lack of vitamin D during childhood can lead to bone deformities like rickets in children, where bones are weakened and bone pain caused by a condition called osteomalacia in adults, a condition where your bones become soft, so bend and break more easily. Low vitamin D levels can increase your risk of osteoporosis.
It also plays a crucial role in immune support, mood regulation, and reducing inflammation. Deficiency can lead to fatigue and low energy, frequent illness, muscle aches and cramps, poor wound healing, depression or low mood and even hair loss. It can also impact your smile.
Dr Fazeela Khan Osborne is a leader in the field of implant and restorative dentistry. She opened her Harley Street practice, One-to-One Dental, nearly 30 years ago and has seen a worrying rise of vitamin D deficiency in her clients.
‘Vitamin D plays a critical role in dentistry due to its significant impact on oral and dental health. From childhood it plays a role in calcium absorption during tooth development and enamel formation,’ explains Dr Osborne. ‘Vitamin D is also important in our immune response throughout life by reducing inflammation and helping to modulate our ability to fight disease such as gum disease and decay in dentistry.
‘Almost half of my patients (45%) over 50 are deficient in Vitamin D, which explains their bone, muscular and teeth problems. Within implant dentistry, vitamin D is vital in bone formation and maintenance around implants, helping to maintain bone density. Therefore, it is a problem that so many are deficient.
Dr Osborne agrees that we should keep taking vitamin D even during a sunny summer.
‘Vitamin D deficiency is relatively common especially in older patients and minority groups. This is due to spending little time in the sun and in the workplace, or being covered for cultural and religious reasons. Limited sun exposure will lead to deficiencies and supplements are advised.
‘Vitamin D deficiency can be seen in patients with increased bone and muscle pain. It can be measured by a simple COVID like test which we have now incorporated into all of our examination check-ups for patients over 55 and in all implant patients.’
What is the Shadow Test?
Did you know your shadow might be the key to solving the hidden vitamin D problem we have? New data from Medichecks, the UK’s leading at-home blood testing service, has revealed that a staggering 58% of 18 to 30-year-olds are showing suboptimal vitamin D levels, even during brighter months – despite longer days and more sunshine!
Young adults are falling behind and experts believe a mix of lifestyle and misconceptions are contributing. They’re spending more time indoors due to remote work and screen-based lives. Taking less supplements, and they believe that ‘summer is enough.’
Dr Natasha Fernando, Medical Director at Medichecks, says your shadow is a strong indicator to alert you to whether your body is producing enough vitamin D. ‘If your shadow is shorter than you, the sun’s rays are strong enough for your skin to make vitamin D. But if it’s longer, or missing entirely, you’re probably not getting enough, even on a sunny day,’ she explains. So, next time you step outside, take a moment to check your shadow. Shorter than you? You’re likely making vitamin D. Longer? Time to consider testing – your health could depend on it.
Medichecks offers a quick and accurate at-home Vitamin D Blood Test, £39, with results reviewed by doctors and delivered securely online.
While spending time in the sun helps, health coach Kathryn Danzey warns about the dangers. ‘The NHS recommends avoiding direct sunlight between 11am – 3pm between March to October; this is when the sun is at its strongest and you’re more prone to skin damage,’ she explains.
The amount of time you should spend in the sun depends on your skin type. For very fair-skinned people (skin type 1), for example, UV radiation starts becoming harmful to untanned and unprotected skin after 5 to 10 minutes. Skin type 6 in comparison, can sit in the sun for over 60 minutes. You can find the table for skin types and exposure here.
How to increase your vitamin D with diet
You can boost your vitamin D levels through diet too. Qualified Nutritionist Emma Thornton and advisor for avogel.co.uk explains.
‘Vitamin D is quite unique because, unlike some other vitamins and minerals, it is classed as a 'pro-hormone'. This means the body is able to create vitamin D itself when conditions are just right. It is thought, for example, that the body manufactures up to 90% of its vitamin D stores from sunlight, which means we rely on diet for around 10% of our intake.
‘In 2016, the Scientific Advisory Committee on Nutrition (SACN) reviewed its evidence on vitamin D and health. As a result of this research, it is now recommended that everyone over the age of 1-year should have 10μg (400IU) of vitamin D daily.’
A.Vogel’s Balance Mineral Drink offers one means of topping up your vitamin D intake as each sachet contains 5IU. This sensible dose is in addition to other essential nutrients including magnesium, calcium, potassium and zinc. Together these can work well together and aid muscle health, energy and bone maintenance - in addition to eating vitamin D-rich foods, of course, as well as getting out in the sunshine where possible.
Emma takes us through some foods with high levels of Vitamin D.
1. Oily fish
Oily fish including salmon, mackerel, tuna, sardines and herring have some of the highest vitamin D quantities of any food. A small fillet of salmon (around 155g), for example, contains roughly 815IU of vitamin D. As oily fish is such a good source of vitamin D, a fish oil supplement can also be used to top up levels.
2. Products fortified with vitamin D
The likes of butter, some fruit juice and some cereals are now fortified with vitamin D to help keep levels topped up. In 2011, for example, one of the UK's best-known cereal producers, Kellogg's, announced that they were fortifying cereals with extra vitamin D. In 2018 they increased the vitamin D quantity in their cereals further in response to ‘chronic low levels of this essential vitamin in the UK.’
Unfortunately, in the UK, our fresh milk isn't generally fortified with vitamin D as it is in countries such as the USA and Canada, so we should get it via other means. However, if you live outside the UK, this is another way to add to your vitamin D intake.
3. Almond milk
To produce almond milk, nuts are soaked in water, blended and then strained. At this point they can then be fortified with vitamin D, plus other ingredients are occasionally added such as salt or honey for added flavour.
Almond milk also has the benefit that it is suitable for vegetarians and vegans. There are very few vegan sources of vitamin D so this group more or less have to rely on fortified foods or supplements to get enough. This is unless, of course, they get excellent all-year-round sun exposure (and have good liver and kidney function to help with absorption).
4. Red meat
For those whose diets will allow it, red meat, offal and liver can provide additional vitamin D. One 25g steak, for example, contains around 15 IU of vitamin D, whilst 100g of braised beef ribs contains approximately 27IU.
However, too much red meat may interfere with our digestion, so it is important that you don't overload on this food. It is recommended we eat no more than 70g of red meat each day and no more than 1.5mg of liver (and liver paté) a day.
5. Mushrooms
Mushrooms are another vegetarian and vegan source of vitamin D. Unusually, the quantity of vitamin D in mushrooms increases when they are exposed to UV light. Button mushrooms are perhaps the most popular variety, but don't forget that the likes of shitake mushrooms also contain vitamin D.
6. Egg yolk
One large egg yolk contains around 37IU of vitamin D whilst a whole cup of egg yolks holds 530 IU. This indicates that, of all the foods on this list, egg yolks are one of the most abundant in vitamin D, weight for weight, that is.
Egg yolks can be cooked into tasty meals like omelettes but I wouldn't throw away any of the whites if you do this. Egg whites are a good source of protein, and we wouldn't want to miss out on this so make use of the complete egg instead.
7. Cheese
There is roughly 24IU of vitamin D in a 100g portion of cheddar, ricotta, blue cheese and goat's cheese. This occurs naturally in each variety and so cheese does not need to be fortified with vitamin D, as is the case with some other dairy products. Naturally-occurring, food-state nutrients are always best in my book!
The recommended portion size for hard cheese is 30g (about the size of a small matchbox), so make sure you are sticking to this next time you are preparing a cheesy meal or snack!
Could this be the new ‘vitamin D’?
New York Times bestselling author and health guru Ben Azadi is an expert on Vitamin D. In his book Metabolic Freedom, Ben explores the most important vitamins and the most natural ways we can boost them.
Ben says, ‘Every single function inside your body is dependent on metabolism, which comes from the Greek metabole, meaning to change or transform. Your metabolism takes different substances, such as protein, carbohydrates, fats, body fat, sunshine, and oxygen, and transforms them into energy.
‘Most people think of melatonin as merely a sleep supplement, but research reveals that its benefits extend far beyond sleep. In fact, melatonin plays a significant role in metabolism. As we know, healthy mitochondria are crucial for fat loss and longevity, and melatonin is the most potent antioxidant for these cellular powerhouses. Every cell in your body, except red blood cells, contains mitochondria, and these mitochondria produce their own melatonin.
‘Melatonin is nothing to fear. On the contrary, it can be a powerful ally in our modern world, where we are bombarded by stressors that can shut down our cellular energy production. Without proper adaptation to these stressors, disease is likely to follow. To age gracefully, consider making melatonin a part of your nightly routine, especially after the age of 40 or 50.
‘The study ‘Is Melatonin the ‘Next Vitamin D’?’ reviews the expanding understanding of melatonin’s functions beyond sleep regulation. It highlights melatonin’s antioxidant properties, its role in immune function, and its influence on mitochondrial health, comparing it to vitamin D in terms of its wide-ranging health effects.’
Can you take too much vitamin D supplements?
Yes! Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart. If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people.
Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful. Always seek medical advice.
You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you're out in the sun for long periods to reduce the risk of skin damage and skin cancer.
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