As a fat-soluble vitamin, Vitamin D is responsible for many bodily functions, including calcium absorption and bone health. Vitamin D is naturally produced by the skin when exposed to sunlight, but it can also be obtained from food and supplements.
Vitamin D deficiency occurs when the level of vitamin D in the blood is too low. This can happen for various reasons, such as:
Lack of sun exposure: People who live in areas with less sunlight, wear sunscreen or clothing that covers most of the skin, or have darker skin may not produce enough vitamin D from the sun.
Poor diet: People who do not eat enough foods that contain vitamin D, such as fatty fish, egg yolks, cheese, and fortified milk, may not get enough vitamin D from their diet.
Malabsorption: People who have certain medical conditions that affect the absorption of fat-soluble vitamins, such as celiac disease, Crohn’s disease, or cystic fibrosis, may not absorb enough vitamin D from their food or supplements.
Kidney or liver disease: People who have chronic kidney or liver disease may not be able to convert vitamin D into its active form in the body.
Obesity: People who have a body mass index (BMI) of 30 or higher may have lower levels of vitamin D in their blood, as vitamin D is stored in fat tissue and may not be released into the bloodstream.
Age: People who are older than 65 may have reduced ability to produce and use vitamin D in the body.
Vitamin D deficiency can cause various symptoms, depending on the severity and duration of the deficiency. Some of the common symptoms include:
Low vitamin D levels can result in osteomalacia (softening of the bones) in adults and rickets (deformities of the bones) in children.
In addition to affecting muscle function, vitamin D plays an important role in the contraction and function of muscles. Low levels of vitamin D, especially in the legs and arms, can cause muscle aches, cramps, and weakness.
Low levels of vitamin D may lead to fatigue, low mood, or depression. Vitamin D produces serotonin, a neurotransmitter that regulates mood, sleep, and appetite.
It is common for infections and illnesses to occur: Vitamin D aids the immune system in fighting bacteria, viruses, and other pathogens. Low levels of vitamin D can impair the immune system, increasing the likelihood of infection, such as colds, flus, and respiratory infections.
As Vitamin D is involved in the growth and repair of cells, low levels of vitamin D may also cause loss of hair, thinning, or brittleness, as well as skin problems, like dryness, itching, or eczema.
The main form of vitamin D in the blood is 25-hydroxyvitamin D (25(OH)D), so a blood test can be used to diagnose vitamin D deficiency. 25(OH)D levels normally range between 20 and 50 nanograms per milliliter (ng/mL), although this may vary depending on the lab and reference values. A 25(OH)D level below 12 ng/mL is considered deficient, while a level between 12 and 20 ng/mL is considered insufficient.
The amount of vitamin D required to treat vitamin D deficiency depends on the severity of the deficiency, the age, the weight, and the health status of the individual, as well as the amount of vitamin D consumed. Most adults need 600 international units (IU) or 15 micrograms (mcg) of vitamin D per day, while adults over 70 need 800 IU or 20 mcg. Some patients may need higher doses of vitamin D to correct the deficiency, as prescribed by their doctor. The upper limit of vitamin D intake for adults is 4,000 IU or 100 mcg.
Vitamin D deficiency can be prevented by following these tips:
You should get at least 15 minutes of sun exposure on your face, arms, and legs, two or three times a week, preferably between 10 a.m. and 3 p.m., when the sun is at its strongest. Use sunscreen if you are going to be in the sun for longer periods of time.
The best way to get enough vitamin D in your diet is to eat foods that are rich in it or fortified with it, such as fatty fish, egg yolks, cheese, and fortified milk, cereal, orange juice, and yogurt.
In case you are at risk of vitamin D deficiency or if you have a diagnosed deficiency, your doctor may recommend vitamin D supplements. Vitamin D3 (cholecalciferol) is the most effective form of vitamin D for the body, so choose supplements that contain it.
You may need to check your vitamin D levels regularly, as advised by your doctor, if you have a history of vitamin D deficiency or a medical condition that affects your vitamin D metabolism. By doing so, you can prevent complications and adjust your vitamin D intake.
In addition to affecting bone health, muscle function, mood, immune system, and overall well-being, vitamin D deficiency is a common and treatable condition. Vitamin D deficiency can be prevented and treated by getting enough sun exposure, eating foods that contain vitamin D, and taking supplements as needed.
