Vitamin D is a fat-soluble vitamin that is produced by our body naturally when there is direct exposure to sunlight on the skin. Additionally, vitamin D can also be obtained from dietary sources.

The major function of vitamin D is to regulate calcium and phosphorus levels, which is important for maintaining healthy bones and their growth. There are other different health benefits of vitamin D, and a deficiency of the vitamin can be associated with several diseases.

So, getting enough vitamin D is important for the proper functioning of the body. In the article, we will discuss why is vitamin D important to our health and the effects of vitamin D deficiency.

Vitamin D importance

Vitamin D is produced in the form of vitamin D2 and vitamin D3. Both are naturally occurring forms of vitamin D, produced when sunlight falls on the skin. So, vitamin D is also called “the sunshine vitamin," and it plays an important role in various body functions, which are mentioned below:

Healthy bones and muscle strength

Vitamin D helps in the absorption of calcium from the digestive tract. It also causes calcium and phosphorous resorption from the kidney. Thus, it increases blood calcium and phosphorous levels. Calcium and phosphorous are essential minerals for bone mineralization and maintaining healthy bones.

When there is a deficiency of vitamin D in children, it can cause a condition called rickets, which is a softening of the bones, causing the bowing of the legs. In adults, a similar condition is called osteomalacia.

Additionally, if there is a chronic vitamin D deficiency, it can cause osteoporosis, a condition in which bones become fragile and increase the risk of fractures.

Furthermore, vitamin D increases muscle strength by preserving muscle fibers, which prevents falls and related injuries.

Hence, the major function of vitamin D is to regulate calcium levels in the blood for healthy bones and muscles.

Fighting disease

Vitamin D also plays a major role in preventing various diseases. Some of the conditions that might be prevented by vitamin D are:

• Heart disease: The immune system plays an important role in the development of heart diseases like heart attack and stroke. Vitamin D helps in the regulation of the immune system, and there is an increased risk of heart disease with vitamin D deficiency. Furthermore, vitamin D improves the flexibility and relaxation of arteries, which in turn helps to control high blood pressure. Thus, vitamin D reduces the risk of heart attack, stroke, and hypertension.
  
  
• Severe infections: Vitamin D is also found to be associated with decreasing the severity of infections like flu and COVID-19 infections. A recent study also found an association between low vitamin D levels and acute respiratory distress syndrome.
  
  
• Cancer: Vitamin D has also been found to inhibit the development of tumors and slow the growth of existing tumors in the breast, ovary, colon, prostate, and brain, with the evidence strongest for colon cancer. It has also been found that vitamin D reduces the mortality associated with these cancers. Additionally, it has been found that vitamin D is beneficial in the prevention of these cancers.

• Type 2 diabetes mellitus: There are studies suggesting a higher concentration of vitamin D is associated with decreased rates of type 2 diabetes mellitus. 

Mood regulation

Vitamin D is thought to play an important role in regulating mood and reducing the risk of depression. Vitamin D supplementation helps people with depression when there is a lower level of vitamin D. 

Additionally, vitamin D levels are also considered a risk factor for conditions like fibromyalgia, and anxiety. Calcium imbalance also causes various mood-related problems, and thus, vitamin D promotes a healthy mood by regulating calcium levels. Mood-related symptoms associated with vitamin D deficiency are low mood, irritability, and anxiety.

Weight loss

In a study conducted among people with obesity, more weight loss was seen in groups taking vitamin D supplementation than in placebo groups. It is suggested that calcium and vitamin D might have appetite suppressing effect, contributing to weight loss.

Although further study is required to support the theory, there seems to be some relationship between vitamin D and weight loss.

Immune function

Vitamin D regulates immune function, and the research is particularly interested in the two different aspects of immune function associated with vitamin D.

One of them is associated with the role of vitamin D in the prevention of autoimmune conditions. The next one is regarding the role of vitamin D in the prevention of infection. Some of the disease conditions related to the abnormality in immune function due to the deficiency of vitamin D are mentioned below.

• Multiple sclerosis: A population-based study in 2018 found that a low level of vitamin D is associated with an increased risk of multiple sclerosis. It might be due to the activity of vitamin D for immune system regulation. The incidence of multiple sclerosis is higher in less sunny areas, which also suggests the role of vitamin D in the prevention of the condition.
  
  
• Type 1 Diabetes: Type 1 diabetes is also lower in sunnier areas like multiple sclerosis. Although it can be due to genetic differences, the role of vitamin D is also suggested by some evidence.
  
  
• Flu and the common cold: The flu infection is far more common in the winter season as compared to the summer. This led researchers to hypothesize that the seasonal variation might be related to vitamin D availability in the summer season. It has also been shown that people with low vitamin D levels report having recent coughs, colds, or upper respiratory tract infections. Additionally, vitamin D boosts the microbe-fighting capacity of immune cells and thus reduces the risk of common infections.

It has also been found that a low level of vitamin D is associated with an increased severity of infections.

• Tuberculosis: Before antibiotics, sunlight and sunlamps were the major modalities of treatment for tuberculosis. Although there is no concrete evidence, it is suggested that vitamin D plays a role in the prevention of tuberculosis.
  
  
• Other autoimmune conditions: Evidence has found that vitamin D supplements are able to reduce the incidence of autoimmune conditions including rheumatoid arthritis, psoriasis, polymyalgia rheumatica, and autoimmune thyroid diseases (Hashimoto’s thyroiditis, Graves’ disease).

Benefits of vitamin D in infants and children

There is rapid bone growth and development during infancy and childhood. So, vitamin D plays an important role in the growth and development of this age group. When there is a deficiency of vitamin D, it can cause softening of bones, which can lead to a condition called rickets, in which there is a malformation of bones and joints.

Vitamin D deficiency also increases the risk of high blood pressure and hypertension in children. It is because the vitamin plays an important role in the elasticity of the arterial wall.

Furthermore, there is a connection between lower vitamin D levels and allergic sensitization in children. It may be due to the immune function of vitamin D. The evidence is suggested by the lower number of hospital admissions for allergies in children from near the equator. 

Benefits of vitamin D in pregnancy

Studies have shown that low vitamin D is associated with pregnancy-related complications such as preeclampsia, gestational diabetes mellitus, and vaginal infections. However, the studies are not conclusive enough to recommend vitamin D supplementation during pregnancy.

An adequate vitamin D intake during pregnancy may be linked to a lower risk of asthma and food allergy development in the offspring.

Symptoms of vitamin D deficiency

There are certain symptoms related to vitamin D deficiency that will help you decide to seek medical care. Some common symptoms of vitamin D deficiency are:

• Tiredness and fatigue
• Muscle pain, or weakness
• Bone and joint pain
• Stress fractures
• Low mood

When you seek medical care for the above-mentioned symptoms, your doctor might order vitamin D levels and provide vitamin D supplements if required. You should also make sure to get vitamin D through sunlight and a diet. Some common food sources of vitamin D are salmon, tuna, herring, cod liver oil, beef liver, egg yolk, shrimp, mushrooms, and foods fortified with vitamin D like milk and cereals.

Conclusion

Vitamin D is an important nutrient required for the proper functioning of the body. It plays a major role in the growth and development of bones; maintaining bone and muscle strength; improving mood and reducing mood-related disorders; weight management; immune function; and the prevention of various diseases. Thus, this explains why is vitamin D important to our health.

Vitamin D is produced in our body when there is sunlight exposure, and it can also be obtained from dietary sources. However, there might be a deficiency of vitamin D due to inadequate sunlight or a lower level of vitamin D in the diet. In such situations, you might experience symptoms of vitamin D deficiency such as bone and muscle pain, weakness, and low mood. If you experience these symptoms, you might need to check your blood vitamin D levels and take vitamin D supplements if required.

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