Energy dipped since the season has changed? This is the supplement you need to be taking, stat

A woman with sunlight on her face.

You'll likely know that vitamin D is not only good for you, but essential for bone, muscle, and nerve health, as well as for maintaining stable energy levels and mood. While we get the fat-soluble vitamin naturally in summer in the UK via sunlight, it's harder to get naturally come winter (thanks, weather).

While there’s a wealth of evidence to show the many benefits of getting your daily dose of vitamin D, a shocking 57% of Brits aren't getting enough of it - despite everyone in the UK being advised to supplement 10mg daily in the colder months, as per the NHS website.

So, why is vitamin D so important? Good question. "Vitamin D is one of the most important vitamins because it has an abundance of uses," says nutritionist for health and fitness app lifesum, Lovisa Nilsson. "It also enhances the body's absorption of other vitamins and minerals like calcium, iron, magnesium, zinc, and phosphate." Mel Wakeman, senior lecturer in Nutrition & Applied Physiology at Birmingham City University, adds that vitamin D "may also have roles in preventing health problems such as cancers, heart disease, diabetes, and viral infections."

Below, some of the country's top nutritionists explain what vitamin D is and why it's so important to supplement. Don't miss our guides to the best magnesium supplements, stress supplements and menopause supplements, while you're at it.

Supplementing Vitamin D in winter is key for mood and mental health - your guide

As we've touched on above, sunlight is our main source of vitamin D (although, it's always important to make sure you're using the best sun protection when soaking up those rare rays).

But what about during the winter months in the UK? "Spending 20 to 30 minutes between 11 am and 3 pm in the sun each day from April to September should enable us to make enough vitamin D to meet our requirements," says Wakeman. "But for the rest of the year, we have a much heavier reliance on other sources."

Symptoms of vitamin D deficiency, according to world-renowned dermatologist Dr. Howard Murad, include fatigue, muscle pain and weakness, weight gain, poor concentration, restless sleep, and headaches.

If you're worried, your GP can do a blood test to check your levels.

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How else can a Vitamin D deficiency affect you?

Below, Doctor Clare Morrison of MedExpress reveals the five signs you might notice if you're deficient in vitamin D.

1. Dull complexion

"Much like all organs, skin needs vital vitamins to function properly, and vitamin D is one of them," shares Doctor Morrison. Noticed that your colouring is a little grey, your under-eye circles are darker, or your skin is lacking in its normal plump or supple texture? Then it might be time to opt for supplements.

"These are common signs that your skin needs more vitamin D, as it's essential for your skin cells to regenerate properly and remain healthy," she explains.

2. Acne or rosacea issues

As well as affecting the general appearance of your skin, vitamin D can reduce inflammation in your skin, which helps to fight certain skin conditions. "You may notice issues with acne and rosacea, as vitamin D can directly impact your blood insulin response," the doctor shares. "With the right amount of vitamin D, your inflammation levels will be lowered which will help with your general skin health."

3. Dry skin

One tell-tale skin sign of a vitamin D deficiency? Dry or itchy skin on your face. "This may occur on areas such as cheeks, chin and forehead, and in some severe cases, those with a deficiency may also develop eczema, this is thought to be caused by an immune system dysfunction," the expert continues. Case in point: studies have shown that vitamin D can be effective in its treatment whether the vitamin comes from direct sunlight, supplement or a topical skin application.

4. Sweating

Last but by no means least, an increase in the amount you sweat is considered one of the first signs of a vitamin D deficiency. "If you're sweating excessively, including on your face, upping your vitamin D could help," Doctor Morrison concludes.

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How much Vitamin D should I be supplementing?

As per the NHS website and the Department of Health and Social Care, adults and any children over the age of four need to take ten micrograms (mcg) of vitamin D a day during the autumn and winter months.

Supplements are available to buy in health stores, like Boots and Holland & Barrett, and also in most major supermarket chains.

Is there such thing as too much Vitamin D?

The experts we consulted for this piece share that it's rare. "Vitamin D toxicity is uncommon and usually only affects people who have been taking vitamin D supplements well above the recommended dosage for several months," shares Wakeman.

Of course, if in doubt, do consult with your doctor if you have any concerns.

Am I at risk of Vitamin D deficiency?

Wakeman shares that any adults living in the UK should consider supplementing the vitamin, simply because we don't get enough sunlight during winter.

That said, according to the 2014 NICE (National Institute for Health and Care Excellence) guidelines, anyone on the list below is considered "at-risk" and so should definitely take a supplement. These include:

1. All pregnant and breastfeeding women
2. All babies and young children from 6 months to 5 years
3. Breastfed infants from one month of age (if their mother has not taken vitamin D supplements throughout pregnancy)
4. People aged 65 years and over
5. People who are not exposed to much sunlight
6. People with a darker skin tone.

Now, if you'll excuse us - we're off to stock up on vitamin D.