Vitamin D is also known as the sunshine vitamin. We know the importance of eating a healthy diet for essential nutrients. But how exactly does one get vitamin D if this is the ‘sunshine vitamin’? Vitamin D is naturally present in very few foods. Some foods like orange juice may contain added Vitamin D. It is also available as a dietary supplement. Since it is found in very few foods, it is produced on the skin in the presence of ultraviolet rays from the sun. They strike the skin and trigger vitamin D synthesis. Vitamin D is important since it helps the body absorb calcium. Calcium forms the building blocks of bone. Therefore, a deficiency of vitamin D can lead to osteoporosis or rickets. Vitamin D is also important for healthy nerve, muscle and immune system.

Functions:

Bone Health: Vitamin D along with calcium, supports bone health. Calcium and phosphorus develop bone structure and strength. It is interesting to note that even if your diet is rich in calcium and phosphorus, without Vitamin D, they are not absorbed by the body. Vitamin D is very important for strong bones. Calcium and phosphorus are essential for developing the structure and strength of your bones, and you need vitamin D to absorb these minerals. Even if you eat foods that contain a lot of calcium and phosphorus, without enough vitamin D, you can’t absorb them into your body. Vitamin D acts by promoting calcium absorption in the gut. This helps maintain adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and teeth.

Immune system: Recently described as the ‘miracle nutrient’, Vitamin D boosts immunity as it helps the body produce antimicrobial peptides. These then fight against infections.

Muscle function: Vitamin D helps to improve muscle function and boosts energy within muscles. Especially in the elderly, this is important since it prevents falls. 

Heart health: Along with fibre and omega 3 fats, vitamin D helps maintain a healthy heart. It improves cardiovascular function, for a healthy heart and good circulation. 

Respiratory system: A lesser known function of the sunshine vitamin, is its importance for healthy lungs and airways. Exposure to sunlight has been known to help with the treatment of tuberculosis. However, only recently was it discovered that vitamin D is a powerful anti-microbial against Mycobacterium tuberculosis.

Brain development: Scientists have studied the relationship between Vitamin D status and brain health. They found that the lower the subjects’ vitamin D levels, the more negatively it impacted their performance on mental tests.

Mental health: Some studies have shown that vitamin D may help in positively impacting mood and warding off depression. The relation between vitamin D and depression was studied. Scientists found that people with depression who took vitamin D supplements had improved symptoms. It was also noted that those who had fibromyalgia (a disorder that causes musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues), experienced anxiety and depression and had low Vitamin D levels.

Deficiency:

Due to its close relationship with bone and muscle health, symptoms of a vitamin D deficiency in adults include severe bone or muscle pain. One may also experience weakness that may cause difficulty climbing stairs or walking.  Severe deficiency results in osteoporosis (brittle bones) which could lead to stress fractures of the legs, pelvis, and hips. 

Deficiency could also impair cognitive outcomes of thinking, behaviour and memory.

Sources of Vitamin D:

Good sunlight exposure- For Indians, based on scientific studies (Harinarayan et.al- Vitamin D status and sun exposure in India), it is recommended that we get sunlight exposure between 11 am to 2 pm for 10 minutes on the exposed areas of our body like the arms. 

Food sources of the sunshine vitamin include- meat, cheese, egg yolk, fatty fish (tuna, salmon, and mackerel), cod liver oil, butter, milk and mushrooms. Fortified foods- cereals, orange juice, soy products and yogurt.