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A Paleolithic-type diet results in iodine deficiency: a 2-year randomized trial in postmenopausal obese women

Manousou S, Stål M, Larsson C, Mellberg C, Lindahl B, Eggertsen R, Hulthén L, Olsson T, Ryberg M, Sandberg S, Nyström HF (2018) Eur J Clin Nutr.  2018 Jan;72(1): 124-129. doi: 10.1038/ejcn.2017.134. 

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Abstract:

BACKGROUND/OBJECTIVES:

Different diets are used for weight loss. A Paleolithic-type diet (PD) has beneficial metabolic effects, but two of the largest iodine sources, table salt and dairy products, are excluded. The objectives of this study were to compare 24-h urinary iodineconcentration (24-UIC) in subjects on PD with 24-UIC in subjects on a diet according to the Nordic Nutrition Recommendations (NNR) and to study if PD results in a higher risk of developing iodine deficiency (ID), than NNR diet.

SUBJECTS/METHODS:

2-year prospective randomized trial in a tertiary referral center where healthy postmenopausal overweight or obesewomen were randomized to either PD (n=35) or NNR diet (n=35). Dietary iodine intake, 24-UIC, 24-h urinary iodine excretion (24-UIE), free thyroxin (FT4), free triiodothyronine (FT3) and thyrotropin (TSH) were measured at baseline, 6 and 24 months. Completeness of urine sampling was monitored by para-aminobenzoic acid and salt intake by urinary sodium.

RESULTS:

At baseline, median 24-UIC (71.0 μg/l) and 24-UIE (134.0 μg/d) were similar in the PD and NNR groups. After 6 months, 24-UIC had decreased to 36.0 μg/l (P=0.001) and 24-UIE to 77.0 μg/d (P=0.001) in the PD group; in the NNR group, levels were unaltered. FT4, TSH and FT3 were similar in both groups, except for FT3 at 6 months being lower in PD than in NNR group.

CONCLUSIONS:

A PD results in a higher risk of developing ID, than a diet according to the NNR. Therefore, we suggest iodinesupplementation should be considered when on a PD.