Investigation of the mineral profile of Fucus serratus Linneaus aqueous extracts and examination of the routes of uptake of minerals both in vivo and in vitro /

Abstract

Seaweed baths are used to promote health and well-being. Seaweed typically contains water, fibre, carbohydrate, protein, lipid, vitamins and minerals. Minerals can account for up to 40% of its composition. Iodine is vital for normal growth and development. Literature indicates that the Irish adult population is iodine deficient (82 μg L-1). Diet is its main source however inhalation of gaseous iodine also occurs. Simulated seaweed baths were prepared throughout the research under varying conditions of seaweed mass and temperature. Spectrophotometric methods, i.e. Sandell-Kolthoff, AAS, FES and ICP-MS, were used to determine the mineral profile of Fucus serratus L. and seaweed bathwater. The Fucus serratus L. mineral content is approximately 2% dry weight based on the minerals measured. On addition of Fucus serratus L. the bathwater pH ranges from 5.29 to 6.36 with an average pH of 5.88±0.26. Lower pH influences the mineral species present; molecular iodine predominates under acidic conditions. The bathwater mineral concentrations increase with increasing mass of seaweed at constant volume however, per gram of seaweed, the relative mineral concentrations decrease. Increasing temperature (20-80 ˚C) leads to a higher efflux of minerals, most significantly between 20 and 40 ˚C. All the minerals studied show a significant difference in concentration over 12 months. Iodine levels are lowest in summer and highest in winter while all other minerals indicate highest levels in summer. The mineral contribution from seawater to the overall bathwater concentration is minimal. Iodine uptake (via inhalation) was studied in vivo with 30 subjects, bathers and non-bathers. Their Urinary Iodine Concentration (UIC), analysed pre and post seaweed bath, indicate a significant increase (p = 0.015) from 76 to 95 μg L-1 following exposure to seaweed baths. In vitro studies indicate that aluminium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium and zinc may have the potential to be taken up by a bather via dermal absorption.