Doctor reveals the five MAIN symptoms of vitamin D deficiency

Dr Corné Hurter

31 May 2026

In the past month alone, there have been over 626,000 UK Google searches for ‘vitamin D’, following data revealing that almost half of UK adults (49.5%) have below-optimal levels of vitamin D.*

With UK Google searches for ‘level of UV’ surging by 112% in the past week,* Dr Corné Hurter, Medical Director for Services and Delivery at AXA Health insurance, advises the nation on how to spot and prevent low vitamin D levels throughout the summer months.

Beyond just sunlight, other factors influence vitamin D levels

Dr Hurter comments, “Vitamin D is a vital vitamin our bodies need. It helps our bodies to absorb and use calcium and phosphates from our diet, which are important for maintaining healthy bones, teeth, muscles and skin.”

“In addition to sunlight, a person's skin pigmentation, age, body weight, underlying medical conditions, medications, and food habits all have a substantial impact on their vitamin D status.

As a result, more people may be at greater risk of vitamin D deficiency even when they spend time outdoors.”

FIVE symptoms of low vitamin D levels and how to spot them

Fatigue
Mood changes
Bone and joint pain
Frequent illnesses
Muscle aches or weakness

Dr Hurter comments, “Symptoms of low levels of vitamin D can be hard to detect, as many are subtle and difficult to spot. However, it can be helpful to be aware of what to look out for to ensure that symptoms can be identified sooner rather than later.

“Vitamin D impacts our body in numerous ways, so symptoms of lower levels can manifest throughout the body. Symptoms of low levels of vitamin D appear when our body is not absorbing enough of the vitamin, and although this can happen at any point throughout the year, symptoms of low levels of vitamin D are commonly experienced in autumn and winter.”

“Lower levels of vitamin D can lead to a deficiency, which, if left untreated, can cause illnesses, such as bone deformities.”

Vitamin D has other important roles in our body, including:

Reducing the chance of heart disease
Regulating blood pressure and inflammatory pathways
Regulating mood and reducing depression
Helping to maintain a healthy immune system

Preventing low levels of vitamin D besides just being outdoors

Dr Hurter reveals, “Our bodies can absorb vitamin D in numerous different ways; so spending time outdoors in the summer sometimes isn’t enough for sufficient vitamin D year-round.”

1. Sunlight

“Although there is no prescribed amount of sunlight our bodies need to produce the right levels of vitamin D, around 10-15 minutes of sun exposure per day can help to maintain healthy levels of vitamin D, but it’s important to do this without risking sunburn.”

“Taking a short walk outdoors on your lunch break, or throughout the day, is a great way to maintain healthy vitamin D during the winter months.”

“In the northern hemisphere, levels of sunlight are at their strongest between late March and early September, and weakest between October and early March. Since our bodies rely on sunlight to make vitamin D, production virtually stops over the darker months, and our reserves naturally deplete, leaving many people deficient by the end of winter. “

2. Diet

“Maintaining a healthy diet rich in foods with vitamin D can support healthy levels in our bodies. However, there are very few foods that contain vitamin D, so you shouldn’t rely solely on your diet.”

“Foods such as oily fish, egg yolks, liver, mushrooms and ‘fortified’ products, contain vitamin D; however, not enough to be your only source, and this is why supplements can be recommended during the winter months”

3. Supplements

“Following a balanced diet and daily exposure to the sun should allow your body to absorb sufficient vitamin D levels. Your body stores excess vitamin D in fatty cells in the body, which can be used when needed in a process called hydroxylation, in which the liver and kidneys turn stored vitamin D into an active form for the body.”

“A daily supplement containing 10micrograms of Vitamin D can be considered between October and March when levels of sunlight are limited or if you have previously been diagnosed with a Vitamin D deficiency by your doctor.”

“Supplements are a great option for boosting vitamin D levels when your body is lacking vitamin D; however, consuming extreme levels of vitamin D can be toxic to the body.”

“Symptoms of vitamin D toxicity, or a vitamin D overdose, can sometimes be mistaken for the symptoms of vitamin D deficiency; therefore, it is crucial to always consult with a medical professional before taking any supplements.”