A boost for brittle bones
Winter is cruel for bone health. With pollution and smog blocking out sunlight, the body finds it difficult to synthesise vitamin D. Exercising and taking supplements help counter the deficiency. Sanchita Sharma tells more.health and fitness Updated: Jan 18, 2009 12:24 IST
Despite a diet seeped in milk and its byproducts, many Indians have bones that are more brittle than cola-guzzling Caucasians, and researchers have come closer to understanding why. “A study done in PGI Lucknow and published in Osteoporosis International linked low bone mineral density in healthy Indians with severe vitamin D deficiency,” said Dr Ambrish Mithal, one of the study authors and a senior consultant of endocrinology at the Apollo Hospital.
Fat-soluble vitamin D helps maintain normal levels of calcium and phosphorus in the blood. It also helps in calcium absorption, which explains why its deficiency makes bones brittle, soft or misshapen. Vitamin D is found in food such as fish and grains but is also synthesised naturally under the skin by the body under the effect of UV rays in sunlight.
“You don’t expect to be deficient in vitamin D in sunny India, but south Asians need more sunlight to synthesise the vitamin because of higher skin pigmentation. In the winter months, the deficiency may be more pronounced as there is inadequate exposure to sunlight because of air pollution and smog,” said Dr Mithal.
Bone clinics are now routinely reporting osteomalacia, a disease in which the bones become weak and misshapen. “I just got a 45-year-old man with such a bad case osteomalacia that he could barely walk. While some cases of osteomalacia are caused by fat mal-absorption — a condition called steatorrhea —the more common cause is vitamin D deficiency,” says orthopaedic surgeon Dr Yash Gulati. Some causes are pancreatic enzyme deficiency, Crohn’s disease, cystic fibrosis, sprue, liver disease, surgical removal of part or all of the stomach, and small bowel disease. Kidney disorders may also cause a deficiency.
Osteomalacia initially leads to difficulty walking and frequent fractures and as the disease advances, the patient gets progressively bed-ridden. Unlike osteoporosis which occurs with advancing age, osteomalacia can strike people young, more so now with erratic eating schedules and fad diets becoming the norm.
Apart from blood tests to measure the amounts of calcium and phosphorus, X-rays of the affected bones and bone biopsy help diagnosis. Calcium and vitamin D supplements can help treat the problem, but in advanced cases, bone deformities may require surgical correction. A calcium intake up to 1.5 gms a day is prescribed along with high doses of vitamin D. “Treatment leads to rapid bone recovery, especially in the spine and hips,” says Dr Gulati.
Vitamin D is found in animal sources such as fish, fish oils, milk and egg. The vitamin D found in milk leads to optimum calcium absorption, making dairy the best source of calcium. A healthy adult needs 500-800 ml of milk (2.5-4 glasses) a day, but most have less than 500 ml.
“In India we drink milk, but not enough. The PGI study showed that 75 per cent of the participants had less than 500 ml of milk a day,” says Dr Mithal. Milk products apart, good vegetarian sources of calcium are ragi and legumes, but since the mineral is not absorbed as readily from plant sources, prescribing vitamin D becomes a must.
Diet apart, there is the sun to contend with. Increasingly, people stay in closed environs and do not step out in the sun because of fears of UV rays. “Half an hour outdoors combined with some aerobic exercise to strengthen the muscles, which in turn offer support to the bone, is the best way to strengthen your bones,” says Dr Gulati.