New York, Nov 11 : Vitamin D supplementation during pregnancy can help reduce rates of asthma and wheezing in children compared to standard prenatal multivitamin, according to a study. Vitamin D is a nutrient from sunlight exposure, diet, or supplements. It is commonly considered essential to bone health but also has a role in autoimmune and other illnesses. The study, based on a review of studies since 2016, links vitamin D deficiency to childhood asthma and wheezing, a major cause of illness in young children. About 40 per cent of kids report daily wheezing at age three. By age 6, 20 per cent are diagnosed with asthma. "Vitamin D deficiency is very common, especially in pregnant women who are not taking supplements," said Scott T Weiss from Brigham Women's Hospital and professor at Harvard Medical School. "Based on our findings, we would recommend that all pregnant women consider a daily intake of at least 4400 IU vitamin D3 throughout their pregnancy, starting at the time of conception," he added. The latest review paper, published in the Journal of Allergy and Clinical Immunology, summarises previous studies as well as genetic findings that further strengthen the possibility of a causal relationship between vitamin D and asthma and suggests several considerations for planning a follow-up study. "We recommend that a follow-up clinical trial should start as early as possible in pregnancy and supplement with 6000 IU vitamin D and seek a very high enrollment of women of colour," said Weiss. "Such trials could deepen our understanding of the potential impact of vitamin D on pregnancy outcomes and early-life asthma." /IANS