Variation of Iodine and Cadmium in Typha Latifolia and Commercial Salts from Busia in Kenya

Abstract

Background to the study: Table salt is a vital food additive needed for adding flavor, pickling, to preserve, curing fish and meat and for tanning. It is an essential ingredient used in baking and cooking to suppress bitterness, improve the tastes, and preserve food. Table salts have additives such as iron used to prevent anaemia and iodine used to prevent goiter. Most of the salt used around the world comes from mines and plant material that tend to be present in soils contaminated with heavy metals. Cd, Fe and Pb are some of the heavy metals found in the environment. Iodine is an essential trace element for human nutrition. The safe dietary intake of iodine as recommended by the World Health Organization (WHO) is 100 μg day−1 for children and 150 μg day−1 for adults. Iodine is necessary for synthesis of T3 and T4 hormones by the thyroid gland. Insufficient iodine leads to iodine deficiency symptoms and disorders like goiter, mental retardation, extreme fatigue and depression which are collectively referred to as iodine deficiency disorders (IDD). The fortification of salt with iodine is an efficient, economical, and steady way of ensuring sufficient iodine ingestion. Objectives: Effect of storage time on the iodine and cadmium concentration in Typha Latifolia reed salt and two selected commercial table salts (Ken salt and Sea salt) from Busia in Western Kenya has been investigated. Methods: Iodometric titration and Inductive Coupled Plasma – Atomic Emmision Spectroscopy were used to determine the concentration of iodine and cadmium respectively. Results: Amount of iodine in the salt is affected by the storage time. The average amount of iodine in mg/ kg of salt, measured every after 15 days for a period of 90 days was in the ranges: indigenous T. latifolia salt (868.0 mg/kg – 385.0 mg/kg); sea salt (214.4 mg/kg - 100.8 mg/kg); ken salt (236.88 mg/kg - 186.12 mg/kg). The percentage loss of Iodine in the salt was highest in T. latifolia reed salt (55.68 %) followed by Sea salt (52.99 %). Ken salt lost 16.67 % of Iodine during the storage time. Amounts of cadmium in mg/ kg of salt, measured every after 15 days for a period of 90 days was in the ranges: indigenous salt (96.5 mg/kg - 32.92 mg/kg); ken salt (20.06 mg/kg - mg/kg); potassium iodate (2260 mg/kg - 2732.52 mg/kg). Amount of cadmium in mg/ kg of salt were in the ranges: indigenous T. latifolia salt (9.65 mg/kg – 17.32 mg/kg); sea salt (32.92 mg/kg – 34.98 mg/kg); ken salt (20.06 mg/kg - 46.52 mg/kg); potassium iodate (2260 mg/kg – 2328 mg/kg). This study provides strong evidence that the amount of iodine reduces over time in the salts. Commercial salts lost smaller percentage of Iodine than reed salt. This could be attributed to the presence of stabilizers in commercial salts. T. latifolia salt had higher levels of Iodine during the first 15 days of production. Therefore, it will be worth recommending consumption of small amount of salt within the first 15 days after production when the concentration of iodine is high or stabilizers can be added to the salt if it is to be used for a longer period of time. This should be done in line with the World Health Organization recommended levels of iodine for human consumption. Consumption of small amount of the salt will minimize the uptake of harmful impurities such as Cadmium. There was no significant change in the levels of Cadmium in the salts with time. However, the levels of Cadmium should be monitored during salt production to ensure the salt is safe for human consumption.