Scientists have tried to estimate the best time of day to expose themselves to the sun and how much is needed to maintain adequate levels of vitamin D. Sunlight with UVB radiation is essential for the synthesis of vitamin D.
Maintaining good bone health is essential for a healthy life. With the onset of the winter season, especially in cities like Delhi, which has more pollution and little chance of sunlight entering, it is difficult to find natural vitamin D. The synthesis of vitamin D in the body is minimized because the quality of sun exposure is reduced. Dr. Vishwadeep Sharma Senior Consultant, Arthroscopy and Sports Injuries, Department of Orthopedics in Fortis Flt. Lieutenant Rajan Dhall Hospital sheds light on the subject.
Generally speaking, about 20 percent of the body, especially the arms and legs, if exposed to sunlight for a minimum of fifteen minutes a day, can help in the synthesis of a good amount of vitamin D. The following Question to be addressed is the most appropriate time of day for exposure to sunlight. In contrast to the myth of the morning and afternoon sun, it is actually the afternoon sun between 10 a.m. and 3 p.m., the most suitable for the synthesis of vitamin D of the skin of the human body. For this, the exposed area of the skin must be free of topical creams that block the sun or other agents.
Cities such as Delhi with high PM content and pollution do not have the quality of the sun necessary for good exposure for vitamin D synthesis, therefore, dietary supplementation becomes important for maintaining good bone health. The reason why sunlight cannot synthesize vitamin D is because pollution in the environment filters UVB radiation.
Especially premenopausal and postmenopausal women are prone to osteoporosis and osteomalacia. Women who are completely covered (HIJAB) and with excessive use of sunscreen creams have lower levels of vitamin D with a decrease in bone density. Osteomalacia in adults and rickets in children are secondary to vitamin D deficiency. This chronic deficiency can cause a lot of disability for the particular age group. These conditions can be completely prevented by measures such as fortification of food and dietary supplements.
Children in the first years of growth should have a proper diet and good exposure to sunlight. Children, especially young children who once weaned breast milk, should be supplemented with foods rich in vitamin D.
Many years ago, research on vitamin D was not up to date, studies in children with good exposure to sunlight showed the cure of their rickets sequel only by exposure to sunlight.
Bone health can be maintained by ensuring a good amount of exercise in the winter season. Exercise affects bone health directly by maintaining bone density that counteracts conditions such as osteoporosis. This is based on the fact that bone metabolism is essentially a balance between the mineral deposited in the bone and the hormones in the body. Hormones with an impact on bone health are PTH (parathyroid hormone), thyroid hormone and estrogen, progestogen in women.
Vitamin D is also essentially a hormone with its action directly at the level of the nucleus of each and every cell in the body. Personal habits such as smoking, excessive alcohol consumption can have a severe effect on bone metabolism with worsening osteoporosis and it is better to avoid them.