Low-level seaweed supplementation improves iodine status in iodine-insufficient women

Abstract

Iodine insufficiency is now a prominent issue in the UK and other European countries due to low intakes of dairy products and seafood (especially where iodine fortification is not in place). In the present study, we tested a commercially available encapsulated edible seaweed (Napiers Hebridean Seagreens w Ascophyllum nodosum species) for its acceptability to consumers and iodine bioavailability and investigated the impact of a 2-week daily seaweed supplementation on iodine concentrations and thyroid function. Healthy non-pregnant women of childbearing age, self-reporting low dairy product and seafood consumption, with no history of thyroid or gastrointestinal disease were recruited. Seaweed iodine (712 mg, in 1 g seaweed) was modestly bioavailable at 33 (interquartile range (IQR) 28-46) % of the ingested iodine dose compared with 59 (IQR 46-74) % of iodine from the KI supplement (n 22). After supplement ingestion (2 weeks, 0·5 g seaweed daily, n 42), urinary iodine excretion increased from 78 (IQR 39-114) to 140 ) mg/l (P,0·001). The concentrations of thyroidstimulating hormone increased from 1·5 (IQR 1·2-2·2) to 2·1 (IQR 1·3-2·9) mIU/l (P,0·001), with two participants having concentrations exceeding the normal range after supplement ingestion (but normal free thyroxine concentrations). There was no change in the concentrations of other thyroid hormones after supplement ingestion. The seaweed was palatable and acceptable to consumers as a whole food or as a food ingredient and effective as a source of iodine in an iodine-insufficient population. In conclusion, seaweed inclusion in staple foods would serve as an alternative to fortification of salt or other foods with KI.

Biomass soaking treatments to reduce potentially undesirable compounds in the edible seaweeds sugar kelp (Saccharina latissima) and winged kelp (Alaria esculenta) and health risk estimation for human consumption

“…The observed I bioavailability from Laminaria hyperborea for I-sufficient women (90%) was significantly higher than for I-insufficient women (62%). The results from in vitro bioavailability assays suggested the role of the seaweed polysaccharide matrix in delaying the I absorption, hence a slower I release from seaweed ingredients compared to foods enriched with KI (Combet et al 2014).…”

In vitro evaluation of antimicrobial and antioxidant activities of algal extracts

“…Although brown algae are of lesser nutritional value than red and green algae, they contain important bioactive compounds. Ascophyllum nodosum is a large, common cold water brown alga and is one of the most used seaweed in animal nutrition, it is rich in minerals, particularly potassium and iodine (Combet et al 2014) and contains polyphenols and phlorotannins, enlisted as bioactive compounds (Munir et al 2013;Makkar et al 2016). Algal biomass can also have a positive impact on food security and the environmental impact: in fact, they are cheap to harvest and grow exclusively in water, preventing the use of arable land.…”

Effect of diet supplementation with Ascophyllum nodosum on cow milk composition and microbiota

“…Because the brown macroalga Ascophyllum nodosum contains many nutritional components such as polysaccharides, fatty acids, polyphenols, peptides (Phaneuf et al, 1999) and the iodine content varied from 482 μg/g (Phaneuf et al, 1999) to 712 μg/g (Combet et al, 2014), meals or extracts of this alga have been examined as natural feed supplements to improve animal health and performance in the following species: lambs (Archer et al, 2007) and cattle (Kannan et al, 2007;Karatzia et al, 2012), young pigs (Turner et al, 2002), and grower-finisher pigs (Gardiner et al, 2008). Moreover, this alga has been reported to cause a short-term decrease of core body temperature (T core) in cows (Archer et al, 2007) and to improve immune function during heat stress, without affecting performance (Archer et al, 2007;Karatzia et al, 2012).…”