Soaking up the sun

Study finds a 30-minute sunbath is enough to make infants vitamin D-sufficient

Woman Holding a Baby

It used to be a routine in India to massage infants and then give them a sunbath. But changing lifestyles over the years have more or less put an end to this practice and children now spend most of their time indoors. This has led to the emergence of vitamin D deficiency as a major problem among infants.

Study findings

A study in New Delhi now suggests an estimate for the minimum time infants need to be exposed to sunlight every day to acquire sufficient levels of vitamin D in their body.

Doctors at the University College of Medical Sciences, New Delhi, enrolled 100 infants in the study and asked their mothers to record the time, duration and the body area exposed during a sunbath every day, beginning six weeks of age.

The study found that an exposure of as low as about 30 minutes per week with about 40% of the child’s body exposed to sunlight can help achieve adequate vitamin D status at six months of age. The researchers also found that the ideal time to have a sunbath is between 10 a.m. and 3 p.m.

Dramatic impact

“This small intervention can help improve levels of vitamin D in infants without the need for supplements or formula feed, and can possibly benefit more than 16 million babies born in the country every year,” says Dheeraj Shah, professor of paediatrics at the University College of Medicine Sciences, and a co-author of the study.

The study took into account factors such as the skin colour of infants and the season of the sunbath. About 90% of the mothers in the study were themselves vitamin D-deficient. Mothers who were on vitamin D supplements were excluded so that the study results remained unaffected, the researchers explain. The study and its results have been published in the journal Indian Pediatrics.

“We are planning further studies with a larger group of infants to test it as an intervention therapy,” says Piyush Gupta, corresponding author of the paper.

Vitamin D is synthesised in the skin when the sun’s ultraviolet rays convert a molecule, 7-Dehydrocholesterol, on the skin into an inactive form of the vitamin. This enters the blood circulation and is converted to its active form in the liver and kidney.

A matter of concern

Several studies over the years have shown that more than 50% of the Indian population is vitamin D-deficient. This is a matter of concern especially for infants because vitamin D is important for calcium absorption, normal growth and development, and maintenance of bone health and hair follicles. Insufficient levels of the vitamin cause lethargy, irritability, and a predisposition towards infections. Extreme deficiency can causes rickets, which results in a malformation of the (leg) bones. — India Science Wire