You may know all about vitamin C, but do you know why vitamin D is also important to your body? Experts from the Children’s Hospital in Boston, US, have said that some teens don’t get enough of this important nutrient. 

　　Vitamin D is necessary to develop healthy bones. It is produced by the body with the help of sunlight. It can also be found in certain foods and drinks, such as livers and eggs. However, it is difficult to get enough vitamin D from food alone, which means enjoying the sunshine is very important. 

　　The doctors who ran the study tested 307 adolescents to discover how much vitamin D was in their blood. They found that 74 of the children tested-nearly 25 percent-had vitamin D deficiency. Of those 74, 14 were severely short of the nutrient. 

　　The doctors also found that the amount of the vitamin found in a child’s blood was affected by a number of factors. Vitamin D levels drop in winter, probably because less time is spent outside in the sunlight. Diet was also a key factor. 

　　Even skin colour has an influence, as people with darker skin find it more difficult to produce the vitamin. 

　　Vitamin D deficiency can lead to many health problems for both children and adults. It is also believed that low levels of it can cause depression.

　　辅助阅读：

　　美国波士顿儿童医院的专家称，有些青少年不能获取足够的维生素D。缺乏维生素D会引起很多健康问题。维生素D是骨质健康成长所必需的。维生素D含量低还可能引起抑郁症。而阳光有助于人体生成维生素D。研究发现，某些食物（如动物肝脏和鸡蛋）和饮料含有维生素D，但人体单纯从食物中不能获取足够的维生素D。所以，晒太阳对人体来讲非常重要。