Study: Trace Elements (2011) & Night Blindness
Learn more about night blindness.
Although night blindness is most often considered a side effect or symptom of other eye diseases in developed countries, in developing countries where childhood nutritional deficiencies are common vitamin A deficiency is associated with night blindness.
Knowing the vitamin A deficiency was the most direct cause of night blindness, the researchers wanted to evaluate deficiencies of trace elements in children who have night blindness.
They compared levels of zinc, coper and iron in the hair, blood and urine of children aged 3-12 with night blindness as compared to controls of matched age and gender who did not have night blindness.
They found that the children with night blindness had markedly lower levels of iron, zinc and copper in their hair and blood.1
In a separate project, the researchers assessed levels of zinc, magnesium, calcium, potassium, sodium, arsenic, cadmium and lead in the blood, hair and urine of children aged 3 to 12 with matched controls who did not have night blindness.
The researchers found that arsenic, cadmium, sodium, and lead were markedly higher in the samples. These elements, of course, have a toxic effect on the body to begin with. The researchers found lower levels of zinc, calcium, potassium and magnesium in hair and blood, but higher levels of those elements in urine samples.2
1. H.I. Afridi, T.G. Kazi, et al., Evaluation of status of zinc, copper, and iron levels in biological samples of normal children and children with night blindness with age groups of 3-7 and 8-12 years., Biological Trace Element Research, September, 2011.
2. H.I. Afridi, T.G. Kazi, et al., Evaluation of essential trace and toxic elements in biological samples of normal and night blindness children of age groups 3-7 and 8-12 years, Biological Trace Element Research, October, 2011.