Who Needs Vitamin D?
Vitamin D. Who might need it and how to get it.
Vitamin D, often called the "sunshine vitamin," as it can be synthesised in most healthy individuals after careful and limited sun exposure, plays an essential role in maintaining our overall metabolism and health. It can support strong bones, boost the immune system, and even impact mood.
While some people get enough vitamin D naturally, others may need to supplement or adapt their lifestyle to maintain healthy levels.
In this health edit, I’ll give you the lowdown on who might benefit from taking vitamin D, how to test your levels (in the UK, different options may be possible elsewhere), foods that contain it, and how to maximise absorption. I'll also discuss the role of supplements and other nutrients that may support vitamin D's effectiveness.
Who might benefit from vitamin D supplementation?
Sub-optimal or deficient Vitamin D is common, especially in regions with limited sunlight. Individuals who may benefit from supplementation include:
People with Limited Sun Exposure: If you spend a lot of time indoors, live in northern climates, or cover your skin for cultural or medical reasons, your body may struggle to produce enough vitamin D for your body to store it, particularly to see you through winter until the sun becomes stronger again in spring.
Older Adults: As we age, our skin becomes less efficient at synthesising vitamin D from sunlight. Additionally, older adults are at higher risk of bone diseases like osteoporosis.
Darker-Skinned Individuals: Melanin reduces the skin's ability to produce vitamin D, making supplementation beneficial for those with darker skin tones living in areas with low UV levels.
Pregnant and Breastfeeding Women: Vitamin D is essential for maternal health and the baby’s bone development.
People with Certain Medical Conditions: Conditions like Crohn’s disease, coeliac disease and obesity can impair vitamin D absorption or metabolism.
Those with Bone Health Concerns: Individuals at risk of osteoporosis, frequent fractures or even rickets, cases of which are once again rising in number in the UK, may benefit significantly from adequate vitamin D levels.
Testing vitamin D levels (in the UK)
Testing your vitamin D levels is recommended before any supplementation. Here’s how you can do it:
NHS Test: If your doctor suspects a deficiency, they can request a blood test. However, access to NHS testing may vary and is typically reserved for individuals with symptoms of severe deficiency, such as bone pain or muscle weakness.
Private Testing: Numerous private providers offer finger-prick blood tests that can be done at home. These tests analyse your blood sample for 25-hydroxyvitamin D, the main form measured to assess levels. Results typically range from:
Deficient: Less than 25 nmol/L
Insufficient: 25–50 nmol/L
Adequate: Above 50 nmol/L
Vitamin D in food
Whilst sunlight is the best source of vitamin D, some foods provide small amounts. These include:
Oily Fish: Salmon, mackerel, and sardines are good sources. For example, 100g of cooked salmon contains around 10–20 micrograms (mcg) of vitamin D. In the UK, mackerel is currently one of the most sustainable oily fish. Its prime season is June to September, but fresh gutted and cleaned whole mackerel or fillets can be frozen for a few months; despite what some people say about freezing it, it is fine, I’ve tested it!
Egg Yolks: Eggs contain around 2 mcg of vitamin D per yolk, with free-range or organic eggs typically having higher levels due to increased sun exposure.
Fortified Foods: Some products, such as breakfast cereals, plant-based milks, and orange juice, may be fortified with vitamin D (it’s good to be aware of the ultra-processed nature of some fortified foods, however; read the labels as many contain all sorts of unhelpful things that can mess with our gut health, including excessive amounts of sugar).
Liver: Beef liver is a nutrient powerhouse, providing about 1 mcg of vitamin D per 100g serving.
Mushrooms: Certain mushrooms, especially those exposed to UV light, can contain significant amounts of vitamin D2, a plant-based form. Download my free guide on how to make mushrooms your own secret ingredient, including how to get the most from them in terms of Vitamin D, along with some seasonal mushroom recipes. Even I’m converted, and they used to be my least favourite vegetable!
Maximising vitamin D from your food
Clever Cooking: Avoid overcooking oily fish, as this may reduce vitamin D content.
Store Mushrooms Properly: Leave mushrooms on a windowsill in sunlight for 15-30 minutes, before consuming to enhance their vitamin D levels.
Supplements: Types and considerations
For those unable to meet their vitamin D needs through sunlight or diet, supplements are a convenient option. Supplementation of any kind should be undertaken after discussion with a nutritional therapist or another suitably qualified healthcare provider.
Types of vitamin D:
Vitamin D2 (Ergocalciferol): Derived from plants, often found in vegan supplements.
Vitamin D3 (Cholecalciferol): Derived from animal sources or lichen (for vegans). D3 is more effective at raising blood levels of vitamin D.
Dosage:
The NHS currently recommends 10 mcg (400 IU) daily for adults.
Higher doses may be prescribed for certain health conditions or goals, but exceeding 100 mcg (4,000 IU) daily without medical advice can be harmful.
Formulations:
Tablets and capsules are common.
Liquid drops or sprays may be more suitable for children or those who find swallowing difficult.
Nutrients that may assist Vitamin D absorption
Vitamin D works best when paired with certain vitamins and minerals:
Calcium: Vitamin D helps the body absorb calcium, crucial for bone health. Foods rich in calcium include:
Dairy products (milk, cheese, yoghurt)
Leafy greens (e.g., broccoli, kale)
Fortified plant-based milks
Magnesium: This mineral is vital for converting vitamin D into its active form. Good sources include:
Nuts and seeds (e.g., almonds, pumpkin seeds)
Whole grains (e.g., brown rice, quinoa)
Dark chocolate – yes!
Vitamin K2: This vitamin complements vitamin D by directing calcium to the bones instead of arteries. Sources include:
Fermented foods (e.g., sauerkraut, kimchi)
Egg yolks
Grass-fed dairy and meats
Tips for optimising Vitamin D absorption
Take with food: Vitamin D is fat-soluble, so consuming it with a meal containing healthy fats such as good olive oil or whole fat plain yoghurt improves absorption.
Pair with magnesium: A balanced diet rich in magnesium can enhance the effectiveness of vitamin D.
Regular monitoring: If you’re supplementing, periodic testing ensures you stay within safe levels. I recommend a review of any supplement you are taking after 3 months, with a registered nutritional therapist or other qualified healthcare professional.
Conclusion
Vitamin D is an essential nutrient that supports numerous aspects of health, from strong bones to a robust immune system. While sunlight is the most efficient source, dietary adjustments and supplements ensure adequate levels for those at risk of deficiency. Pairing vitamin D with calcium, magnesium, and vitamin K2 through a varied diet further enhances its benefits.
If you suspect you’re not getting enough vitamin D, consider testing your levels and consulting a healthcare professional. By making small but meaningful changes, you can enjoy the many benefits of this vital nutrient.
Get in touch if you’d like more tailored support.