ZINC AND ESSENTIAL FATTY ACIDS MODULATE BONE GROWTH AND METABOLISM IN RATS

Abstract

The effects of zinc and essential fatty acids (EFAs) on bone growth and metabolism were studied in young growing rats.  Female weanling rats were maintained on diets deficient in EFAs, low in zinc (6 ppm) or both deficient in EFAs and low in zinc.  Femur weights of rats maintained on EFA-deficient diet low-zinc diet or double-deficient diet were decreased by a factor of 0.32, 0.39 and 0.47 respectively, when compared with rats on control diet.  The factor for the corresponding decrease in bone length was 0.08, 0.08 and 0.46 respectively.

    Feeding of deficient diets to rats resulted in lower alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities.  This reduction is due to reduced enzyme synthesis as well as loss of enzyme due to tissue decalcification.  The low-zinc status aggravated EFA-deficiency, causing a higher reduction in bone growth as well as ALP and LDH activities.  It is considered that: (a) the deficiencies of EFAs and zinc cause bone decalcification, and (b) ALP and LDH play significant roles in the early stages of the calcification process but that their activities are inhibited by EFA and zinc deficiency states.