New Delhi, Nov 30 (IANSlife): Maintaining good bone health is prime for a healthy life. With the setting of the winter season, especially in cities like Delhi which has more pollution and little scope for sun rays to make its way through, natural vitamin D is hard to come by. Vitamin D synthesis in the body is reduced to a bare minimum because the quality of sun exposure is reduced. Dr. Vishwadeep Sharma Senior consultant, Arthroscopy & Sports injuries, Dept of Orthopaedics at Fortis Flt. Lt. Rajan Dhall Hospital sheds light on the subject.

Many studies have been conducted to estimate the best time in the day to get sun exposure and how much of the sunlight is needed to maintain adequate levels of Vitamin D. The Sunshine with UVB radiation is the Radiation essential in the synthesis of Vitamin D.

Broadly speaking about 20 percent of the body, especially 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 next question to be addressed is the time of the day best suited for the exposure to sunlight. As against the myth of early morning and late evening sunshine, it is actually the afternoon sun between 10 am to 3 pm which is most apt for the synthesis of the vitamin D from the Skin of the human body. For this, the exposed area of the skin has to be free from any topical sun-blocking creams or other agents.

Cities like Delhi with high PM content and pollution don't have the quality of sunshine required for good exposure for the synthesis of Vitamin D, hence dietary supplementation becomes important for maintaining good bone health. The reason for sunshine not able to synthesize Vitamin D is because the pollution in the environment filters the UVB radiation.

Women especially pre-menopausal and the post-menopausal category are prone to osteoporosis and osteomalacia. Women who cover themselves fully (HIJAB) and with excessive use of sunblock creams have lower levels of Vitamin D with decreased bone density. Osteomalacia in adults and rickets in children are secondary to deficiency of Vitamin D. This chronic deficiency can cause a lot of disability for the particular age group. These conditions are entirely preventable by for measures like fortification of foods and dietary supplements

Children in the early years of growth have to have adequate dietary as well as good sunlight exposure. Children especially toddlers once weaned off the mother's milk have to be supplemented with foods rich in Vitamin D.

Many years back ago the vitamin D research was not up to date, studies conducted on children with good sunlight exposure showed healing of their rickets sequel just by sunlight exposure.

Bone health can be maintained by ensuring a good amount of exercise in the winter season. Exercise impacts bone health directly by maintaining bone density which counters conditions like 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. The hormones with impact on bone health are PTH (Parathyroid Hormone), Thyroid hormone and estrogen, progestogen in the 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 like smoking, excessive alcohol use can have a severe effect on bone metabolism with worsening of Osteoporosis and are best avoided.