Unfortunately, many people seem unaware of is how crucial vitamin D is for keeping bones and teeth healthy.
But with the distinct lack of sunny weather (sunshine being a vital source of vitamin D) as well as our substandard eating habits - the average UK household only manages to consume 4 portions of fruit and veg per person per day - a deficiency is more common than you think.
According to the NHS, a lack of vitamin D can result in bone deformities in children, as well as bone pain and tenderness in adults.
There's no excuse to not get your fill as your daily dose can come from all shapes and forms including: salmon, mushrooms, eggs, tuna, milk, pork, cereal and sunshine (when we're blessed with it).
In fact, you can even take supplements to boost your dosage.
But what happens if you're not getting enough of the stuff? Signs of a vitamin D deficiency include:
:: Muscle weakness
:: Lowered stamina
:: Chronic pain
:: Depression
:: Increased blood pressure
Research has shown that during winter and spring in the UK, one in six adults will suffer from a vitamin D deficiency.
Juliette Kellow, expert nutritionist for Fish is the Dish, notes the importance of eating oil-rich fish to up your dose of vitamin D.
She also adds that there's now evidence of low Vitamin D levels in most age groups of people living in the UK: “This is especially true for older children and young adults.
"Eating at least one portion of oil-rich fish a week could help to improve Vitamin D status so it’s important that parents consider this when planning the family’s weekly meals,” she says.
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7 Signs You Have Vitamin Deficiency
According to Gloria Halim, a holistic health coach, if you think you might be deficient then it's best to visit your doctor and ask for a blood test.
"Chronic vitamin D deficiency cannot be reversed overnight," she adds.
"It takes months of vitamin D supplementation and exposure to sunlight to rebuild the body's bones and nervous system so it would be a good idea as part of daily routine to supplement and eat foods that have some amount of vitamin D present to prevent becoming deficient."