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Title: Iodine in the vegan diet
Author: Lightowler, Helen
ISNI:       0000 0001 3609 9426
Awarding Body: South Bank University
Current Institution: London South Bank University
Date of Award: 1997
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Various potential nutrient deficiencies associated with the vegan diet have been thoroughly investigated, but limited research has been undertaken to assess the iodine intake of vegans. Moreover, such research may be considered unreliable. Therefore, the aims of the current work were to firstly ascertain the main sources of iodine in the vegan diet, both dietary and pharmacological, and their frequency of consumption. Secondly, it was intended, by way of a prospective cross-sectional study, to determine the iodine intake of vegans consuming their habitual diet, and their iodine status. The current sources of iodine in the vegan diet and the frequency of consumption were assessed in 378 replies to a questionnaire advertised in 'The Vegan' - the official magazine of the Vegan Society. The main sources of iodine were identified as seaweed and seaweed products, iodised salt and iodine supplements. Over 1 in 4 of the volunteers were not consuming any of these sources and 54% were consuming only one source. Conversely, 19% were consuming at least two of the three identified sources. The preliminary findings suggested that vegans may be at risk of both iodine deficiency and toxicity and that iodine consumption was largely dependent on the iodine content of the food, the portion size and the frequency of consumption. Thirty 'healthy' vegans were recruited to the prospective study. Duplicate portions and 24 hour urine specimens were collected concurrently over four consecutive days and the iodine intake and status determined by chemical analysis. Dietary intake was also recorded and iodine intakes were determined by Comp-Eat, a computerised nutritional analysis program, to assess the reliability of this dietary survey technique. The iodine intake of the majority of the subjects was below the RNI and even below the LRNI. Moreover, the iodine status of the majority of the group investigated was low. Conversely iodine intakes of those who consumed seaweed approached levels which may be considered toxic. These findings indicate that iodine intakes may be low, however it is uncertain as to whether or not the body is able to adapt to such intakes. Furthermore, the potential effect on thyroid function of possibly toxic, but infrequent, intakes of the trace element is unclear. Finally, the study exposed a need for the availability of reliable information on iodine for vegans.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Thyroid function