Vitamin D is known as the sunshine vitamin because our body produces it when we are exposed to sunlight. It is a fat-soluble vitamin and can also be obtained from foods such as green leafy vegetables, eggs, salmon, cod liver oil, and mushrooms, though in limited amount.
The most popular function of vitamin D is to maintain the levels of calcium and phosphorus in the blood. But according many reputed journals, vitamin D not only plays a major role in maintaining bone and muscle health, it also helps in an array of other body functions.
10 reasons why we need vitamin D
- It acts as an immune system regulator. According to researchers from the University of Colorado Denver School of Medicine, Massachusetts General Hospital and Children’s Hospital Boston, vitamin D arms the immune system against disorders like common cold.
- Vitamin D may reduce the risk of developing multiple sclerosis.
- It is required for optimum functioning of the brain.
- According to the Medical College of Georgia, vitamin D also helps maintain body weight.
- Research by The London School of Medicine and Dentistry found that having adequate vitamin D levels may speed up the recovery of tuberculosis patients undergoing antibiotic treatment.
- A Harvard Medical School study suggests that vitamin D reduces the severity and frequency of asthma symptoms.
- It has also been shown to reduce the risk of developing rheumatoid arthritis in women.
- Studies by the Cancer Treatment Centers of America also suggest that people who have enough vitamin D are less susceptible to cancer, compared to people with lower levels of the vitamin. It also found that regardless of the nutritional status, cancer patients had vitamin D deficiency.
- The New York City Department of Health and Mental Hygiene found that vitamin D also plays a role in our body’s mechanism that prevents damage from low levels of radiation.
- Studies by the Katholieke Universiteit Leuven, Belgium suggest that vitamin D may also play a role in preventing hypertension by limiting the action of certain enzymes that are responsible for an increase in blood pressure.
Lack of this vitamin can cause serious health problems. Recent research shows that a person with vitamin D deficiency for longer periods is at a higher risk for chronic diseases such as certain kinds of cancer, heart disease and diabetes. Let’s learn more about vitamin D deficiency…
Vitamin D deficiency is seen in adults as well as children. However, in the initial stages, it is difficult to spot the lack of the vitamin in the body, as often the symptoms are either ambiguous or absent.
Infants with severe vitamin D deficiency may experience muscle cramps due to low calcium levels. They may also suffer from bone deformities, soft bones and bow-shaped legs [known as rickets and osteomalacia]. Stunted growth, late walking, late teething, irritability and being prone to infections are some other symptoms.
Fatigue and depression are the most common symptoms. In addition, adults lacking in this vitamin experience muscle weakness. Studies show that vitamin D deficiency is prevalent in almost 80 per cent of people across all age groups. In severe cases, it leads to osteoporosis.
Insufficient exposure to sunlight is a principle cause. The other causes of deficiency include:
- The major sources of vitamin D are animal-based products such as dairy foods, beef liver, eggs, fish, and fish oils. Thus, strict vegetarians do not get enough of this vitamin from their diet.
- Vitamin D is converted to its active form by the kidneys. As we age, our kidneys become less functional in converting vitamin D to its active form.
- People with dark skin may suffer from vitamin D deficiency as the high amount of melanin reduces the body’s ability to absorb sunlight.
- Diseases such as Crohn’s disease [inflammatory bowel disease], coeliac disease [a condition that damages the lining of the small intestine], and cystic fibrosis [a disease that causes thick, sticky mucus to build up in the lungs and digestive tract] are also responsible for the drop in vitamin D levels.
How much of vitamin D is enough?
Vitamin D is now considered as a pro-hormone and not just a vitamin. The Indian Council of Medical Research [ICMR] recommends outdoor physical activity [for sun exposure] as a means of achieving both adequate vitamin D and controlling weight in addition to dietary suggestions.
But did you know that to get the desired result, the sunlight needs to fall directly on bare skin [not through a window or glass pane]? Just make sure that you do not overdo it as excess exposure may harm the skin.
According to International Osteoporosis Foundation [IOF], the average vitamin D requirement of older adults is 800IU – 1000 IU[IU=International Unit]. However, further research shows that children need at least 400IU – 1000 IU of vitamin D a day, while teenagers and adults need at least 2000 IU vitamin D per day to satisfy their body’s vitamin D requirement.
In short, for healthy vitamin D levels, people of all age groups should engage in outdoor activities [without sun blocks], eat a healthy balanced diet, watch their weight, and take vitamin D-fortified foods or fish/cod liver oil supplements.
References: Curr Drug Targets. 2011 Jan;12(1):4-18,
Osteoporos Int. 2010 Jul21(7):1151-4
With inputs from Rekha Sharma, President of the Indian Dietetic Association and director, clinical nutrition and dietetics at the Diabetes Foundation [India].