Iodine intake and iodine deficiency in vegans as assessed by the duplicate-portion technique and urinary iodine excretion.
I intake and I deficiency were investigated in thirty vegans (eleven males and nineteen females) consuming their habitual diet. I intake was estimated using the chemical analysis of 4 d weighed duplicate diet collections. The probability of I-deficiency disorders (IDD) was judged from the measurement of urinary I excretion in 24 h urine specimens during the 4 d. There was wide variation in I intake. Mean I intake in males was lower than the reference nutrient intake (RNI; Department of Health, 1991) and mean intake in females was above the RNI, although 36% males and 63% females had I intakes below the lower RNI. Mean I intake in subjects who consumed seaweed (n 3) was in excess of the RNI, and approached the provisional maximum tolerable daily intake (World Health Organization/Food and Agriculture Organization Joint Expert Committee on Food Additives, 1989). The probability of IDD in the group investigated was moderate to severe: three of five subgroups were classified as moderate and two subgroups were classified as severe IDD possibility. The findings highlight that vegans are an 'at risk' group for I deficiency. The I status of vegans and the subclinical effects of low I intakes and infrequent high I intakes on thyroid function in this group should be further studied. Our work has also raised the question of adequate I intakes in groups where cow's milk is not consumed, and has exposed a need for more research in this area.
Lightowler
H J
HJ
Nutrition Research Centre, School of Applied Science, South Bank University, London, UK. lightohj@sbu.ac.uk
Davies
G J
GJ
D000328:Adult; D000704:Analysis of Variance; D003430:Cross-Sectional Studies; D014676:Diet, Vegetarian; D004435:Eating; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage* / Q000172:deficiency* / Q000652:urine; D008297:Male; D009752:Nutritional Status; D012307:Risk Factors
D007455:Iodine