Vitamin A deficiency

Vitamin A deficiency is a lack of vitamin A in humans. It is common in developing countries but rarely seen in developed countries. Night blindness is one of the first signs of vitamin A deficiency. Xerophthalmia and complete blindness can also occur since Vitamin A has a major role in phototransduction. Approximately 250,000 to 500,000 malnourished children in the developing world go blind each year from a deficiency of vitamin A, approximately half of which die within a year of becoming blind. The United Nations Special Session on Children in 2002 set the elimination of vitamin A deficiency by 2010. The prevalence of night blindness due to vitamin A deficiency is also high among pregnant women in many developing countries. Vitamin A deficiency also contributes to maternal mortality and other poor outcomes in pregnancy and lactation.
Vitamin A deficiency also diminishes the ability to fight infections. In countries where children are not immunized, infectious disease like measles have higher fatality rates. As elucidated by Dr. Alfred Sommer, even mild, subclinical deficiency can also be a problem, as it may increase children's risk of developing respiratory and diarrheal infections, decrease growth rate, slow bone development, and decrease likelihood of survival from serious illness.

Vitamin A deficiency is estimated to affect approximately one third of children under the age of five around the world. It is estimated to claim the lives of 670,000 children under five annually. Approximately 250,000-500,000 children in developing countries become blind each year owing to vitamin A deficiency, with the highest prevalence in Southeast Asia and Africa. According to the World Health Organization (WHO), vitamin A deficiency is under control in the United States, but in developing countries vitamin A deficiency is a significant concern.

Vitamin D may reduce the risk of cancer

Cancer researchers urged people on Wednesday to take more vitamin D to lower their risk of colon, breast and ovarian cancer, saying studies showed a clear link.

"Our suggestion is for people to increase their intake," through diet or a vitamin supplement, Dr. Cedric Garland said in a telephone interview.

Garland's research team reviewed 63 studies, including several large long-term ones, on the relationship between vitamin D and certain types of cancer worldwide between 1966 and 2004.

He said the benefit of vitamin D was as clear as the harmful link between smoking and lung cancer.

"There's nothing that has this ability to prevent cancer," he said, urging governments and public health officials to do more to fortify foods with vitamin D.

Garland is part of a University of California at San Diego Moores Cancer Center team that published its findings this week online in the American Journal of Public Health.

The paper concluded that vitamin D deficiency may account for several thousand premature deaths from colon, breast, ovarian and other cancers annually.

Vitamin D is found in milk, as well as in some fortified orange juice, yogurt and cheeses, usually at around 100 international units (IU) a serving.

People might want to consider a vitamin supplement to raise their intake to 1000 IUs per day, Garland said, adding that it was well within the safety guidelines established by the National Academy of Sciences.

The authors said that taking more vitamin D could be especially important for people living in northern areas, which receive less vitamin D from sunshine.

African Americans, who don't produce as much of the vitamin because of their skin pigment, could also benefit significantly from a higher intake, the authors said.