?CASSAVA,PROTEIN AND IODINE INTERACTION IN THE THYROID STATUS OF RATS

Abstract

The possible synergistic role of dietary cyanide from cassava,low iodine intake and protein deficiency and/or imbalance on the
thyroid status and goiter endemia in Akungba and Oke-Agbe villages in Akoko area of south-western Nigeria was investigated
using rats as model. Thirty (30) weaning albino rats were fed on corn starch or cassava as the major source of carbohydrates,
3.5 and 10.0% levels of protein supplied by either casein or Amaranthus viridis and a salt mixture with or without iodine
for 42 days. Cassava with a total hydrocyanic acid (HeN) content of 25 mg kg' DW did not cause growth depression when
fed to rats with casein at 10% protein level. Iodine deficiency resulted in slightly higher weight gain while protein defi-
ciency especially the vegetable rations caused significant growth reductions. Interaction between cassava/iodine deficiency
and protein imbalance, especially in the vegetable rations, caused a significant increase in the weight of the thyroid gland
when expressed as percent of body weight. Dietary cyanide caused a significant increase in serum and urinary thiocyanate
levels while iodine deficiency caused a significant reduction in the plasma protein-bound iodine (PBI). These results
would partially explain the goiter endemia in Akungba and Oke-Agbe villages whose nutritional status was mimicked in
these experiments.