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Get a sunshine fix

Known as the sunshine vitamin (it is formed in the skin by exposure to the sun’s UV-B rays), Vitamin D is essential for the absorption of calcium.  

Mrs. S, a physically active professional in her late fifties, suffered from repeated muscle pain. Despite various forms of therapy, it was never completely resolved. Finally the doctor ordered a test to measure Vitamin D levels. The problem was due to low levels of the vitamin. After about 12 weeks of taking supplements, the pain disappeared completely.

Another case was that of 16-month-old Vinu. His anxious parents brought him to the paediatrician as he hadn’t started walking. His birth history and past medical history were uneventful. A physical examination did not show anything wrong but a blood test showed Vitamin D deficiency. Treatment for the same was initiated and the infant started walking independently very soon.

Known as the sunshine vitamin (it is formed in the skin by exposure to the sun’s UV-B rays), Vitamin D is essential for the absorption of calcium. It also facilitates the absorption of iron, magnesium, zinc and phosphates. One wouldn’t think that Vitamin D deficiency would be a problem in a country like India, which has abundant sunshine all through the year. But this is a growing problem.

Dr. Jayashree Gopal, Senior Consultant, Endocrinologist and Diabetologist, Apollo Hospitals, Chennai, offers an example of how crucial it for calcium absorption. “With Vitamin D, 70 per cent of calcium in the diet may be absorbed. Without it, it is only 20-30 per cent.”

Sports physician Dr. Kannan Pugazhendi (Founder-Director, Spaarc Institute) agrees. “The calcium that is absorbed in the intestine is vital for normal development of bone in infants and children. During childhood, the establishment of healthy bones that do not alter in shape due to weight bearing is crucial.”

Dr. Meena Venkatraman, Consultant Paediatrician, Cloudnine Hospital, Bangalore, says that deficiency of Vitamin D in young children can lead to “a variety of skeletal deformities classically known as rickets, weakness of proximal muscles with symptoms such as delayed onset of walking in infants and difficulty climbing stairs in adolescents.” It can also cause bone pain, stress fractures and osteoporosis, apart from affecting other organs. Dr. Vijay C. Bose, Joint Director and Consultant Orthopaedic Surgeon, Asian Joint Reconstruction Institute, SRM Institute for Medical Science, Chennai, points out, “Vitamin D also prevents skin diseases such as chronic urticaria and psoriasis. It is also needed for good mental health. Deficiency of Vitamin D during pregnancy may increase risk for Type 1 Diabetes, arthritis, multiple sclerosis and schizophrenia.”

Though it is early days yet, research has shown that Vitamin D deficiency is associated with increased risk of colon, prostrate, breast and pancreas cancer, higher prevalence of diabetes, obesity, rheumatoid arthritis and hypertension.

The production of this vital vitamin has to do with exposure to the sun. Dr. Venkatraman elaborates, “The main source has been via synthesis in the skin from a specific cholesterol after exposure to UVB light. Full body exposure during summer months for 10-15 minutes in an adult with lighter skin will generate between 10000 and 20000IU (International Units) of Vitamin D3 within 24 hours. Individuals with darker pigmentation require 5-10 times more exposure.”

Dr. Gopal adds, “More Vitamin D is made when sunlight hits the skin at 90°, say, around noon. When we start to feel the burn in the skin is when the vitamin has been made. UV rays cannot penetrate through clothes or glass, so exposure of as much bare skin as possible (minus sunscreen) is needed. Vitamin D levels may be lower in women because they are more covered up. In older people, the level of the specific cholesterol drops so less Vitamin D is made even with exposure to sunlight.” With industrialisation and pollution — more pollution means less UVB — the problem of vitamin D deficiency has become a global issue.

“The season of the year when exposure occurs and the latitude are also of consequence,” says Dr. Pugazhendi. “Those who live closer to the equator receive more exposure than those living closer to the poles. Obesity is another cause because an individual with increased muscle mass requires more Vitamin D.” Incidentally patients with some intestinal, liver and renal disorders and those on certain drugs are also likely to suffer from compromised levels.

With supplements being the treatment option, Dr. Gopal offers a cautionary note: “Vitamin D is a fat-soluble vitamin and is stored in the fat for long periods unlike water-soluble vitamins (B vitamins) which are easily excreted. Therefore there is a danger of taking too much Vitamin D without medical supervision. Toxic levels can cause headaches, vomiting, and raised pressure in the brain. That said supplements work well when needed.”

Few dietary sources

Fatty fish (tuna, salmon, mackerel, herring, shrimp, and sardines), cod liver oil, beef liver, cheese, egg yolk and shitake mushrooms.

Fortified foods like milk, milk products, juices and cereals are an option but these are not easily available in India as yet.


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Printable version | Oct 16, 2021 9:15:43 AM | https://www.thehindu.com/features/magazine/get-a-sunshine-fix/article7040069.ece

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