Environmental and human iodine and selenium status: lessons from Gilgit-Baltistan, North-East Pakistan

Abstract

Iodine and selenium deficiencies are common worldwide. We assessed the iodine and selenium status of Gilgit-Baltistan, Pakistan. We determined the elemental composition (ICP-MS) of locally grown crops (n = 281), drinking water (n = 82), urine (n = 451) and salt (n = 76), correcting urinary analytes for hydration (creatinine, specific gravity). We estimated dietary iodine, selenium and salt intake. Median iodine and selenium concentrations were 11.5 (IQR 6.01, 23.2) and 8.81 (IQR 4.03, 27.6) µg/kg in crops and 0.24 (IQR 0.12, 0.72) and 0.27 (IQR 0.11, 0.46) µg/L in water, respectively. Median iodised salt iodine was 4.16 (IQR 2.99, 10.8) mg/kg. Population mean salt intake was 13.0 g/day. Population median urinary iodine (uncorrected 78 µg/L, specific gravity-corrected 83 µg/L) was below WHO guidelines; creatinine-corrected median was 114 µg/L but was unreliable. Daily selenium intake (from urinary selenium concentration) was below the EAR in the majority (46–90%) of individuals. Iodine and selenium concentrations in all crops were low, but no health-related environmental standards exist. Iodine concentration in iodised salt was below WHO-recommended minimum. Estimated population average salt intake was above WHO-recommended daily intake. Locally available food and drinking water together provide an estimated 49% and 72% of EAR for iodine (95 µg/day) and selenium (45 µg/day), respectively. Low environmental and dietary iodine and selenium place Gilgit-Baltistan residents at risk of iodine deficiency disorders despite using iodised salt. Specific gravity correction of urine analysis for hydration is more consistent than using creatinine. Health-relevant environmental standards for iodine and selenium are needed.

Joint Biofortification of Plants with Selenium and Iodine: New Field of Discoveries

“…Moreover, plants can convert highly toxic inorganic soil Se forms into well-absorbed organic derivatives with more powerful protective effect [ 7 ]. Considering the widespread Se and I deficiency within the populations of many countries worldwide [ 8 ], the importance of the joint plant Se–I biofortification is apparent [ 9 ].…”

Emerging roles of selenium on metabolism and type 2 diabetes

“…Global estimated daily intake of selenium and prevalence of diabetes. Data for the global estimated daily selenium intake are adapted from the published studies (95)(96)(97)(98)(99)(100)(101)(102). The selenium data of mainland China was selected.…”

Advances in the study of selenium and human intestinal bacteria

“…Among these, Brazil nuts, are one of the foods with the highest Se content, ranging from 1.80 to 320.80 μg Se/g ( 5 ). In addition, selenium intake is also regionally related, and studies have found that in areas with low soil selenium content, selenium levels in drinking water and crops are generally low, resulting in inadequate selenium intake by the local population ( 6 ). In China, 72% of the soil environment is deficient in selenium, which cannot meet the human body's demand for selenium ( 7 ).…”