Researchers from the National Institutes of Health in the US report that animal studies have already shown that dietary folate can increase tissue concentrations of docosahexaenoic acid (DHA), a fat thought to protect against heart disease and also depression and mental disorders.
But no human studies have examined the possibility that folate status may affect plasma DHA concentrations.
The team carried out a retrospective study on 15 normal and 22 hostile and aggressive subjects, with a mean age of 38 years.
Concentrations of plasma polyunsaturated essential fatty acids and red blood cell folate were obtained prior to 1996, before American flour was enriched with folate.
Folate was significantly correlated with plasma DHA in the aggressive group, they report in an advance online issue of the European Journal of Clinical Nutrition (doi:10.1038/sj.ejcn.1602321).
Age, smoking and alcohol consumption did not alter the results. No other essential fatty acids were significantly associated with RBC folate in either group.
"The positive relationship between plasma DHA and RBC folate concentrations suggests that these two nutrients should be examined together in order to make the most accurate inferences about their relative contributions to disease pathogenesis," concluded the researchers.
"Our findings present one explanation why some conditions associated with hostility and low DHA status, such as cardiovascular disease and emotional disorders, are also associated with low folate status," they added.