Studies on some trace and minor elements in blood. A survey of the Kalpakkam (India) population. Part III: Studies on dietary intake and its correlation to blood levels.

In our studies on elemental levels in blood of the Kalpakkam population, it was found that the reference values for many elements were normal, but some deficiency with respect to Se was noticed. As a followup study, the dietary ingredients of the local population were analyzed for trace and minor elements to assess the dietary intake of these elements. Details of the analytical methods developed using the technique of inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) have been described. The dietary intake of many of these trace and minor elements were found to be quite adequate according to the recommended dietary allowance (RDA) levels prescribed, except for Se and Zn. The dietary intake of Se was found to be in the range 20-50 micrograms/d (as opposed to the RDA of 50-200 micrograms/d), whereas the intake of Zn was found to be in the range 8-10 mg/d (as opposed to the RDA of 15 mg/d). Although the deficiency of Se intake was reflected in the blood, that of Zn was not, probably owing to the high level of homeostasis for this element. Fish and egg were found to be rich sources of Se, followed by cereals and pulses, which were found to be the major sources of Zn.