Despite Israel's sunny skies, a large proportion of young ultra-Orthodox Jewish women there have been found in a study to suffer from vitamin D deficiency.
The research, comprising 156 ultra-Orthodox ("haredi") new mothers and 186 secular Jewish counterparts, pointed to religiously dictated fashion as the culprit. Long sleeved dresses, high necklines, opaque stockings, hats, and other headgear worn for reasons of modesty even in the summer can cause women to have inadequate stores of vitamin D and put them at high risk of osteoporosis in middle and old age.
Professor Yosef Weisman, director of the bone disease unit at Tel Aviv's Ichilov Hospital, found that 40% of haredi women suffer from inadequate supplies of the vitamin because they rarely expose their skin to the sun.
As a result of his study, published in the Israel Medical Association Journal (2001;3:419-21), he recommended that haredi women—especially those who are pregnant—should be prescribed vitamin D supplements.
The study compared obstetrics patients at the haredi Mima'ayanei Hayeshua Hospital (in the almost totally haredi city of Bnei Brak) with non-religious women who delivered at Ichilov Hospital in nearby Tel Aviv. Only 16% of the secular women were found to have inadequate vitamin D stores.
Professor Weisman suggested that haredi women tend to get little outdoor exercise (when they do go swimming, they go to sex segregated beaches and pools and even there will cover themselves up), thus reducing their exposure to the sun.
Only 15% of haredi women who received vitamin D supplements during pregnancy had deficits of the vitamin. Because their fertility averages twice that of secular Israeli Jewish women, each pregnancy may further reduce their stores of vitamin D in the skin, Professor Weisman continued.
He did not study modern Orthodox women, some of whom dress almost as modestly but generally have fewer children and go out in public more.
Unlike countries with more temperate climates, where milk must be fortified with vitamin D, there is no such law in Israel—apparently due to the mistaken belief that the sunny weather ensures adequate production of vitamin D from precursors in the skin.
Professor Weisman noted that overexposure to sunlight was harmful and that half an hour of normal outdoor activity while exposing the face, neck, and parts of the arms and legs was enough to prevent a vitamin D deficiency.
He said that his study had implications for other modestly dressed populations, including Bedouin and Muslim women in various parts of the world.
His study had some similarities to a small study of American haredi teenagers published in the May issue of Pediatrics [online] (2001;107:e79). The article ("Reduced spinal bone mineral density in adolescents of an ultra-Orthodox Jewish community in Brooklyn"), written by researchers at Maimonides Medical Center, Brooklyn, and at Byrd Regional Hospital in Louisiana, reported on 30 haredi boys and 20 haredi girls aged 15 to 19.
They were found to have significantly lower spinal bone mineral density than their non-haredi counterparts, partly because of lack of exposure to sunlight. The boys—who study from morning to night in closed rooms—had "profoundly lower" spinal bone mineral density than the haredi girls, who spend more time outdoors.