While iodine deficiency goitre is common worldwide, it is rarely described in the U.K. Vegan diet is the only real way for this deficiency to occur in the U.K. A MEDLINE search from 1966 revealed 1 reported case (Shaikh et al. Transient neonatal hypothyroidism due to a maternal vegan diet; Journal of Pediatric Endocrinology & Metabolism Jan 2003). We have identified 3 cases, which we will describe here.
A 21-year-old female noted incidental gradual development of goitre. TSH 4.10micromole per litre, fT3 5.4picomole per litre, fT4 <5picomole per litre. There was no evidence of autoimmunity. Thyroid ultrasound scan showed symmetrical enlargement of both lobes of the thyroid. Following administration of Iodine 150micrograms daily as part of a multivitamin tablet her thyroid function normalised (TSH 0.4micromole per litre, fT3 5picomole per litre, fT4 13picomole per litre) associated with some subjective reduction in goitre size.
A 17-year-old female presented with weight gain and tiredness. She was found to have a small central goitre. TSH was within the normal range as were thyroid peroxidase and microsomal antibodies.
Thyroxine was given in sufficient dose to suppress TSH with a view to goitre shrinkage. No change in goitre size was noted. She subsequently commenced iodine replacement with kelp (140-280milligrams) daily and noted subjective shrinking of goitre.
A 36-year-old female noted development of goitre over a 2-year period. TSH 0.42micromole per litre, fT3 5.6picomole per litre. There was no evidence of autoimmunity. Following dietary supplementation with kelp, the goitre diminished in size (right lobe 2.2x3.6centimetres from 4x5centimetres; left lobe 3.6x5.2centimetres from 5x6.5centimetres).
Vegan diet is associated with iodine deficiency, potentiating the development of goitre. It is important that individuals are educated regarding appropriate trace element supplementation. In addition dietary history remains intrinsic to the assessment of goitre.