As winter approaches, many of us ramp up our supplement game to support energy, immunity and mood. But if you’re not checking which type of vitamin D you’re taking, it might not be helping — and could even be making things worse.
The supplement market is booming and one nutrient consistently tops the list — vitamin D.
Known as the ‘sunshine vitamin’, it’s considered essential for our health. But how much do we really know — or think to question — about what’s inside the supplements we take?
Most people don’t realise there are actually two types of vitamin D: D2 and D3. Recent research has raised questions about one of them, suggesting it might be less effective — and, in some cases, could even lower levels of the more beneficial type. So, if you’re taking it daily to support your health, it’s worth checking which kind you’re using.
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Why is vitamin D important for everyday health?
Vitamin D isn’t just another trending supplement. It’s essential for strong bones, a resilient immune system and even basic mood regulation.
“It helps control calcium and phosphate in the body, which are key nutrients for keeping bones, teeth and muscles healthy, and reduces the risk of fractures as you age,” explains Peter Thnoia, superintendent pharmacist at online NHS pharmacy PillTime.
Since the body produces vitamin D from sunlight, it’s especially important in winter. It helps fight infections, boosts energy and can even support mood during the darker months — that’s why the NHS recommends taking a daily vitamin D supplement from October to March.
But not all vitamin D supplements are created equal — and choosing the wrong type might mean you don’t get the benefits you expect.
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What are the different types of vitamin D?
There are two main types of vitamin D in supplements: D2 and D3.
- Vitamin D2 comes from plant and fungal sources, such as certain mushrooms and yeast, especially when they’re exposed to ultraviolet light.
- Vitamin D3 is produced by your skin when exposed to sunlight and is also found in foods such as oily fish, egg yolk and liver. Supplements are often derived from lanolin (sheep’s wool fat) and lichen.
Until recently, vitamins D2 and D3 were considered more or less interchangeable — both raise vitamin D levels, of course, but research shows that D3 is generally more effective at maintaining them.
In 2023, a study by Frontiers in Immunology at the University of Surrey found that D2 and D3 don’t, in fact, support immune function in the same way. D3 appears to have a stronger effect on the immune system, potentially offering better protection against viral and bacterial infections.
“That’s why many healthcare professionals favour D3, especially during the darker months,” says Peter.
Why is vitamin D2 bad for your health?
A recent study by the University of Surrey suggests that vitamin D2 can actually lower levels of vitamin D3 in the body.
This a problem because it could limit the (slightly stronger) benefits usually associated with vitamin D3, such as better immunity, energy and bone health. So, over time, low D3 can lead to fatigue, frequent illness and weakened bones and muscles.
“In children, vitamin D2 deficiency can cause rickets, leading to soft or misshapen bones, delayed growth and bowed legs. In adults, it can result in osteomalacia, causing bone pain and muscle weakness,” warns Peter.
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Which type of vitamin D should we take?
Peter points out that there’s no need to panic, but it’s wise to check what you’re taking. For most people, D3 is the preferred option, unless you’re vegan or a strict vegetarian, in which instance, the plant-based vitamin D2 is more suitable.
D2 is less effective and may hinder the body’s ability to absorb and use vitamin D efficiently. It’s not necessarily toxic, but it’s a good reason to check which type of vitamin D you’re taking.
Professor Martin Warren, chief scientific officer at the Quadram Institute, feels stronger, adding: “Vitamin D deficiency is a significant public health concern. Ensuring we use the most effective form — D3 — is key to supporting immune health and overall wellbeing.”
So, if you’re worried, it’s probably best to opt for D3 when you’re browsing the shelves — just check the ingredients on the bottle before you buy.
And in terms of brand, fancy doesn’t mean better. “A cheap calciferol tablet from the supermarket, as long as it’s validated and contains no other ingredients, is just as good as a fancy brand with a gelatine lining or a gummy,” said Professor Warren.
But don’t forget, there are other ways get vitamin D, aside from the sun and supplements. Food like oily fish (sardines, tuna, trout, mackerel), egg yolk, red meat, kippers and fortified cereals are all a good source that are worth prioritising in your diet.
Adults need 10 micrograms (mcg) of vitamin D a day. To put that in perspective, there’s roughly 2.7mcg in one egg yolk or 4.8mcg in one sardine — so, as long as you’re prioritising foods like these during the winter, you should be able to reach your daily target easily.
L360’s vitamin D top picks
The best vitamin D supplements to buy based on value and ingredients.
- Holland & Barrett Vitamin D3, buy 120 tablets for £16.99
- Nutrition Geeks Vitamin D3 One Year Supply, buy 365 tablets for £6.99
- Nature’s Own Vegan High Potency Vitamin D3, buy 60 tablets for £11.12
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How to know if you’re low on vitamin D
Whether you’re taking a vitamin D supplement or not, watch out for these signs you’re deficient:
- Fatigue
- Bone pain
- Muscle weakness
- Mood changes
- Frequent illnesses or infections
- Bone fractures
- Heart disease
If you notice one or more of these symptoms, you should always contact your GP.
Feature image: Pexels
