Studies have increasingly shown that vitamin D, also known as the sun vitamin, plays a vital role in protecting the body from a number of chronic illnesses. It is important to know both the symptoms of a deficiency in vitamin D, and the valuable sources that can provide us with a daily healthy dose.

Insufficient levels of vitamin D in the body can cause pain in the bones and weakness in the muscles, according to Web MD.

Most often, such signals are felt during the winter, when “adults feel discomfort in their bones and muscles and their joints are a little stiffer when they wake up in the morning,” Dr. Michael Holick, a professor of medicine and biophysics at the Boston University Medical Center, told the Huffington Post.

Even your mood can be a clue that your body is not getting enough vitamin D. A group of experts observed this phenomenon in a study. Some volunteers received vitamin D supplements for five days in winter, and another group did not. Those who took the supplements reported a stronger positive emotional state than the participants who did not take the supplements.

Excessive sweating can also be one of the first signs of a vitamin D deficiency, adds Dr. Holick.

Risk factors for a vitamin D deficiency

A deficiency of this substance in the body can be attributed to several causes. First, there may be insufficient exposure to the sun, or a lack of foods that contain vitamin D in one’s diet.

People with darker skin have a lower ability to produce vitamin D from sun exposure, writes Web MD. This is due to the large amount of melanin in darker skin.

At the same time, individuals who struggle with extra pounds and whose body mass index (BMI) exceeds 30, may suffer from a vitamin D deficiency.

Certain conditions and health problems can also affect the levels of vitamin D in the body. This is the case, for example, for those suffering from cystic fibrosis, gluten enteropathy (celiac disease or gluten intolerance), Crohn’s disease, or other conditions that prevent the digestive tract from absorbing vitamin D. A vitamin D deficiency can also occur if the kidneys cannot convert vitamin D into its active form. This often happens with age, writes Web MD.

Why vitamin D is important for the body

Vitamin D is important for bones because it helps absorb and fix calcium and phosphorus, Harvard experts have shown. Moreover, “activated vitamin D is one of the strongest inhibitors of cancerous cell growth. It also stimulates the pancreas to produce insulin. It regulates your immune system,” Dr. Holick told Web MD. Other evidence shows that vitamin D plays an important role in reducing the risk of diabetes, multiple sclerosis, heart attack or rheumatoid arthritis.

The risks we are exposed to due to the lack of this nutrient in the body are worrying. “Vitamin D deficiency, especially in old age, can lead to osteoporosis and osteomalacia (bone decalcification),” says Dr. Lona Sandon of the University of Southwest Texas, Dallas. It can also increase the risk of developing cancer and even tuberculosis, experts at Harvard note.

Foods which contain vitamin D

Vitamin D can be found in foods such as fatty fish (tuna, salmon, trout), milk, orange juice, fortified cereals and egg yolks, writes Health.

You can also use food supplements to compensate a vitamin D deficiency.

Last but not least, sun exposure can help you achieve the required level of vitamin D per day. Dr. Holick recommends 5 to 10 minutes spent in the sun, after which he recommends applying a cream with UV 15 protection factor. It is important to avoid prolonged periods in strong sunlight, as this increases the risk of developing skin cancer.