We know that vitamin D helps our teeth and bones grow stronger, but there are a whole host of reasons why getting enough vitamin D is essential for the healthy running of our bodies. That’s why, if you’re deficient, you may notice you feel more tired or weak.
We spoke to the experts about what vitamin D is, the signs you’re not getting enough and how to boost it if you’re running low…
What is vitamin D?
Vitamin D is a fat-soluble vitamin that our bodies use for bone development and maintenance. “It’s is often called the ‘sunshine vitamin’ because our bodies produce it in response to sunlight,” explains Jessica Sepel, founder of JSHealth Vitamins & Expert Nutritionist. During exposure to sunlight, cholesterol in our skin absorbs UVB rays which creates the energy for vitamin D synthesis to occur.
What does vitamin D do?
According to the NHS, vitamin D helps regulate the amount of calcium and phosphate in the body. Both are essential nutrients for keeping our bones, teeth and muscles healthy. And, alongside fortifying our physical health, it can provide benefits to our mental health, too. “Vitamin D is crucial for strong bones, a healthy immune system and a good mood,” confirms Shenaz Shariff, founder of The Face and Body Clinic, Nutritionist Expert and Member of the British Association for Nutrition and Lifestyle Medicine.
5 signs you’re not getting enough vitamin D
Bone pain
We know that vitamin D is important for maintaining healthy bones, so it tracks that a vitamin D deficiency can lead to bone abnormalities and pain. According to Yale Medicine, “when vitamin D levels are low and the body isn’t able to properly absorb calcium and phosphorus, there is an increased risk of bone pain, bone fractures, muscle pain, and muscle weakness.”
Muscle weakness
As mentioned above, a lack of vitamin D can lead to muscle weakness. A 2018 study noted that vitamin D is increasingly recognised to play an important role in normal muscle function, asserting: “low vitamin D status is associated with an increased risk of falls and proximal weakness.”
The study considered a marked deficiency of vitamin D “clearly detrimental for muscle function,” and added that observational studies also associate muscle weakness, falls and reduced muscle mass with vitamin D deficiency. Whilst the study recommended vitamin D supplementation for those with a severe vitamin D deficiency and vulnerable elderly people, it specified that further research was necessary to establish its benefit for the rest of the population.
Fatigue
Vitamin D is thought to affect our mental health as well as our physical health. Although research is in its infancy, one study from 2019 found that vitamin D deficiency was associated with mental and physical fatigue. Another discovered a prevalence of fatigue in nurses, noting that the profession had a high connection with vitamin D deficiency, given night shifts and work on internal wards limit access to sunshine. A third established a strong association of mental and physical fatigue, with vitamin D deficiency in elderly patients.
Increased illness
“Vitamin D is crucial for immune function, so if you find yourself frequently unwell, a lack of vitamin D could be a contributing factor,” explains Jessica. Scientists discovered that vitamin D is present on almost all cells in the immune system and one study found that a correlation exists between infections and autoimmune diseases and vitamin D deficiency.
Depression
Many people experience feeling more sad in the winter, and others suffer from Seasonal Affective Disorder (SAD) over the darker months. One reason that scientists believe this may be is due to a lack of vitamin D. One study found that vitamin D has properties that can affect the brain tissues involved in the physiological processes associated with depression and anxiety. Another study of 7,534 participants found that vitamin D supplementation can reduce negative emotions, particularly in those with major depressive disorders. More research needs to be done to fully establish the connection.
Why might you be low in vitamin D?
“This deficiency is often due to not getting enough sunlight, especially during winter as your body makes vitamin D when exposed to sunlight,” says Shenaz. “If you spend a lot of time indoors or live in a region with limited sunlight, you could be at increased risk,” adds Jessica. “You could also not be eating enough foods that have vitamin D, like fatty fish or fortified milk,” explains Shenaz.
What can you do to boost vitamin D?
All our experts agreed that the best thing you can do to boost vitamin D is to spend time in natural sunlight each day, particularly from the moths of April to October in the UK, when the rays are strong enough to boost vitamin D synthesis. “Even just 15 minutes of sun exposure per day should be enough to meet your vitamin D requirements,” says Reema Pillai, dietitian at Dietitian Fit. However, they noted that it might not be possible to get the sun exposure needed over the autumn and winter. “The UV rays are not strong enough to allow the body to produce vitamin D,” explains Reema.
“You can also include vitamin D-rich foods in your diet, such as fatty fish and eggs,” says Jessica, but for a boost, “it is advised to take a vitamin D supplement during October to April, or all year around for certain populations who are at higher risk of vitamin D deficiency, such as those who cover their skin when outdoors, or spend little time outdoors, the elderly or those or who have darker skin,” explains Reema.
Can I have too much vitamin D?
Since vitamin D is a fat soluble vitamin, it’s stored in the body for a period of time, rather than ejected (through peeing) like water-soluble vitamins. Therefore, it’s important not to exceed a safe dosage. According to the NHS, “taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart.”