You will need to look at the specific key nutrients needed to support healthy thyroid function: like iodine, iron
status,
assess that you are producing enough stomach acid to convert plant based iron into the absorbable form of iron; you need adequate amounts of selenium,
zinc and cofactors that we get from vitamins A, C, E and the amino acid tyrosine.
Most studies that
assess the effect of fiber intake on mineral
status have looked at calcium, magnesium, iron, or
zinc.