Our bodies rely on certain vitamins and minerals to help keep them functioning to the best of their abilities.
Vitamin D is one such nutrient, found in foods such as oily fish, red meat and eggs.
The majority of the vitamin D we need, however, comes from exposure to sunlight.
This can be a problem in the UK during the autumn and winter months as we get less hours of daylight, leaving people at risk of becoming deficient in vitamin D.
An expert spoke with Express.co.uk about how to spot the warning signs of a vitamin D deficiency and how to prevent it from happening.
Technical and nutritional advisor to Bio-Kult, Claire Barnes, shared six symptoms to look for.
“Whilst many individuals with vitamin D deficiency are asymptomatic, there are a number of signs that could suggest insufficient levels of this important vitamin,” she said.
“These include fatigue, low mood, bone and muscle aches, digestive issues, often feeling ill and even poor oral health.”
Who is at risk of a deficiency?
Many of us are at risk of becoming deficient in vitamin D during the winter.
Claire said: “More than 50 percent of the adult population in the UK appear to have insufficient levels of vitamin D and 16 percent have severe deficiency during winter and spring.
“During the winter period in the northern hemisphere we can expect to see levels of vitamin D drop by 20 to 40 percent.”
It can take more than a month to actually become deficient, Claire said.
She explained: “Levels of vitamin D in the blood can reduce by half the amount within 15 to 25 days.
“However, we’re unlikely to run out of vitamin D within the first month or so of winter, this is because like other fat-soluble vitamins, vitamin D is stored in the body.
“Therefore, it is assumed that vitamin D can be gradually released from storage into the circulatory system to prevent vitamin D levels falling to critically low levels during the winter.”
This means spending the odd day inside isn’t enough to cause a deficiency.
“However those who spend a lot of their time indoors are at risk of vitamin D deficiency or insufficiency,” Claire added.
How to prevent a deficiency
Claire recommended the best foods to keep your vitamin D levels topped up.
“Oily fish (such as fresh tuna, herring, mackerel, sardines and salmon) is the richest source, whilst liver, butter, egg yolk and mushrooms also contain modest amounts,” she said.
“In some countries certain foods such as milk and cereals may also be fortified with vitamin D.”
However, taking a vitamin D supplement daily is advisable during the autumn and winter, she said.
“The amount of vitamin D from food is unlikely to provide the recommended 10 micrograms per day in the UK,” Claire said.
“Everyone should consider taking a daily vitamin D supplement of 10 micrograms during autumn and winter.
“If you’re in a higher-risk group for vitamin D deficiency (such as having darker skin, having limited sun exposure, having certain health conditions, or following a vegan or vegetarian diet) it is advisable to take a supplement all year round.
“A higher dose may be required if your current vitamin D levels are already low.
“I would recommend getting your levels checked and finding out the most suitable dose for you.”
