Ain’t no sunshine? Boost your vitamin D food stores all year round with these key ingredients.
While the majority of our vitamin D comes from exposure to the sun’s rays, in the UK sunshine can be hard to come by, so filling up on vitamin D foods is an easy way to keep your stocks of this essential nutrient topped up. Deficiency is far more common than you might think: at least 10 million Brits have low stores, according to government estimates.
Vitamin D is an essential building block for growth and development, and plays a crucial role in the body’s immune response. So if one in five of us aren’t getting the right amount, it can have serious health implications. The good news is, by adding a few tactical vitamin D foods to your diet, you can stay in optimum health whatever the weather.
We spoke to Sophie Medlin, registered dietitian and owner at City Dietitians, and Dr Louise Durrant, dietitian and science manager at Yakult, to talk us through the facts about the sunshine vitamin – and share the best vitamin D foods to add to your shopping list:
Vitamin D benefits
Vitamin D is essential for several important bodily functions; primarily bone health and immune function, Medlin explains. It regulates your calcium and phosphate levels – two minerals that are essential for keeping your bones and muscles in good shape – and plays a part in activating your immune system defences. Vitamin D also stimulates immune cells, such as T cells and macrophages, while at the same time dampening down inflammation.
Since it’s made from sunlight, vitamin D isn’t technically a vitamin. ‘It’s classified as a prohormone, because it’s produced by the body, unlike other vitamins which come from our diet,’ says Dr Durrant. ‘Just under the surface of our skin is an abundance of a substance called 7-dehydrocholesterol, which is converted to vitamin D when our skin is exposed to ultraviolet (UV) rays of a specific wavelength from the sun’.
Interestingly, there are several different forms of vitamin D to be aware of. ‘In foods and dietary supplements vitamin D comes in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol),’ Dr Durrant explains. ‘Vitamin D2 is produced in plants, whereas vitamin D3 is found in animal products and is also the form that we make ourselves.
‘Vitamin D3 is almost twice as effective at raising vitamin D levels within the body,’ she continues. ‘This doesn’t mean vitamin D2 doesn’t work, and as it’s a plant source, it certainly has its place within vegan diets – D3 is usually made from lanolin in sheep’’s wool – but vitamin D3 may be a more effective choice.’
How much sun do you need?
Between early April to late September in the UK, your body can create vitamin D from the sun’s rays – ‘but the sun is not high enough in the sky to do this in the winter months,’ Dr Durrant continues. What’s more ‘the UV rays needed to make vitamin D can’t pass through a window pane,’ which means if you’re stuck indoors working a desk job, you’re also at risk of deficiency. ‘Make sure you get outdoors and allow your skin to be exposed directly to sunlight for short(!) periods during the spring and summer months,’ she recommends.
If your shadow length is shorter than your height, the sun is high enough in the sky for you to make vitamin D.
If you’re unsure whether the weather’s right, take a look at the length of your shadow. ‘If your shadow length is shorter than your height, the sun is high enough in the sky for you to make vitamin D – but if your shadow is longer than your height, you will not be able to make vitamin D, even if it’s a lovely sunny day,’ says Dr Durrant.
If the conditions are right, you don’t need to stay outside for too long. ‘As little as nine minutes of sun exposure can be long enough to make enough vitamin D for the day, although this does vary for everyone and is influenced by factors including skin tone,’ she adds. The darker your skin, the more sun exposure you’ll need in order to get sufficient vitamin D from the sun.
Are you vitamin D deficient?
If you’re constantly tired, achy, often get ill, or experience bone pain, muscle weakness, or mood changes like depression, you could be vitamin D deficient. ‘Because we are now mostly indoor creatures and we live in parts of the world that don’t get reliable sunlight all year round, we are certainly at risk of deficiency,’ says Medlin.
Left unchecked, vitamin D deficiency can increase the risk of rickets in children and osteoporosis in adults, so it’s worth being aware of the signs. The recommended daily intake for the general population varies according to your age:
- Babies up to the age of one need 10 mcg (400 IU) a day
- Children from the age of one and adults need 15 mcg (600 IU) a day
- If you’re 71 or above, the recommendation increases to 20 mcg (800 IU) a day
If you’re experiencing vitamin D deficiency symptoms, visit your doctor and ask for a blood test. Vitamin D deficiency can be caused by specific medical conditions, such as Crohn’s disease, liver disease, and cystic fibroses, so it’s worth getting checked out for any underlying causes.
If your doctor confirms a deficiency and it’s due to a lack of sun exposure, it’s worth taking a supplement alongside adding vitamin D foods to your diet. When supplements are administered, the maximum recommended vitamin D doses are:
- 1,000 IU per day
- 10,000 IU every seven to 10 days
- or 50,000 IU per month.
Taking more than 100 micrograms (4,000 IU) of vitamin D a day could be harmful to your health.
Generally, everyone is recommended to take a supplement during the chillier months to keep all bases covered. ‘Through the autumn and winter months – from late September to early April – everyone in the UK should consider taking a daily supplement containing 10 mcg (400 IU) of vitamin D,’ says Dr Durrant.
10 of the best vitamin D foods
While sunshine and supplements are the easiest ways to top up your stocks, adding the following vitamin D foods to your diet will help you hit your daily quota:
- Plant-based milk
Unlike other countries, the UK doesn’t fortify its cows milk (although vitamin D-enriched options are available in some stores if you seek them out). However since the majority of plant-based milks – soy, coconut, almond, oat, etcetera – are fortified, they’re an excellent choice for easily incorporating the vitamin into your diet. While the content varies across brands, you can expect to gulp down around 2 mcg in each 250ml glass.
- Fortified orange juice
Not all orange juice is fortified with vitamin D, so you’ll need to look for it on the label. Again, while the content will be different depending on the brand, your average 250ml glass can be reasonably expected to contain approximately 2.5 mcg of vitamin D.
- Mackerel
Fish are a prime source of dietary vitamin D, since they store large quantities in their liver and fat tissues. Each 100g serve of mackerel contains 13.8 mcg of vitamin D per 100g, which is well over your baseline daily recommendation. Not keen on the oily texture? Herring is another rich source, containing 4.2 mcg in the same portion size.
Oily fish are a prime source of dietary vitamin D, since they store large quantities in their liver and fat tissues.
- Eggs
Your average egg contains 1 mcg of the sunshine vitamin, although the true vitamin D levels depend on chickens’ sun exposure and the vitamin D content of their feed. It might not seem like much, but if you’re regularly eating the other vitamin D foods on this list, it’ll soon stack up. The nutrients in eggs are concentrated in the yolk, so be sure to eat them whole. Choose eggs from chickens raised outside, if you can.
- Cod liver oil
If you want a potent vitamin D food hit but can’t stomach the taste of fish, cod liver oil could be the solution. One teaspoon contains 11.25 mcg, although a capsule might be a better bet. Cod liver oil is also an exemplary source of vitamin A, providing 90 per cent of your daily requirements in the same serve. Bear in mind that vitamin A can be toxic in high amounts, so avoid taking too much.
- Mushrooms
One of the only non-fortified sources of plant-based vitamin D foods, mushrooms contain 0.2 mcg per 100g portion. They synthesise the vitamin from sunshine, just like humans – although they produce D2, rather than D3. In the supermarket, look for mushrooms that have been treated with ultraviolet (UV light) – it’ll say ‘vitamin D enriched’ or similar on the packet – or buy regular mushrooms and leave them on the windowsill at home.
- Sardines
You’ll find 4.8 mcg of vitamin D in every 100g serving of sardines. While they’re usually sold canned in water, oil or sauce, you can also buy them fresh, though they tend to perish quickly. Like other oily fish, they’re loaded with healthful omega-3 fatty acids, protein and B vitamins.
- Fortified cereals
Many cereals are fortified with vitamin D, although like other fortified foods, you’d need to compare the labels to find out how they stack up against each other. They’re usually fortified with other nutrients, like iron and vitamin B12, which can be useful for people following a plant-based diet.
Many cereals are fortified with vitamin D, although like other fortified foods, you’d need to compare the labels.
- Salmon
Each 100g portion of salmon contains 10.9 mcg of the sunshine vitamin, making it a worthy addition to our pick of vitamin D foods. But that’s not the only reason this oily fish deserves to be a dietary mainstay – its impressive nutrient profile has been shown to protect the health of your heart, brain and thyroid.
- Beef liver
If organ meats don’t phase you, beef liver contains 1.2 mcg vitamin D, along with vast amounts of vitamin B12, vitamin A, iron, copper, choline, riboflavin, and folate. And when we say vast, we mean it – for example, the same 100g serving contains 3,460 per cent of your daily B12 needs, and 1,620 per cent of your copper requirements. However it’s also high in cholesterol, so avoid eating it too often.
Net Doctor