London: Individuals with Vitamin D deficiency are twice as likely to be diagnosed with schizophrenia as compared to those who have sufficient levels of the vitamin, says a study.
The skin naturally produces this vitamin after exposure to sunlight.
Schizophrenia is a mental disorder with symptoms that can include delusions and hallucinations.
Since schizophrenia is more prevalent in high latitudes and cold climates, researchers have theorised Vitamin D may be connected to the disorder.
"When we examined the findings of several observational studies on Vitamin D and schizophrenia, we found people with schizophrenia have lower Vitamin D levels than healthy people," said Ahmad Esmaillzadeh from Isfahan University of Medical Sciences in Isfahan, Iran.
The researchers reviewed the findings of 19 observational studies that assessed the link between Vitamin D and schizophrenia.
When combined, the studies looked at Vitamin D levels and the mental health of 2,804 adult participants. The studies used blood tests to determine each participant's Vitamin D levels.
People with Vitamin D deficiency were 2.16 times more likely to have schizophrenia than those with sufficient Vitamin D in their bloodstreams, the analysis showed.
The very few foods in nature that contain Vitamin D include the flesh of fatty fish (such as salmon, tuna and mackerel) and cod liver oils. People also obtain smaller amounts of the vitamin through foods, such as milk fortified with Vitamin D.
More than a billion people worldwide are estimated to have Vitamin D deficiency due to limited sun exposure.
The study appeared in the Journal of Clinical Endocrinology & Metabolism.