The randomsed, double-blind, placebo-controlled study found a significantly greater urinary clearance of calcium in women subjects than calcium carbonate, the widely used source of the mineral in foods and supplements.
It is the first human clinical trial on Aquamin, manufactured by small Irish company Marigot, from mineralised seaweed (Lithothamnion sp) harvested off the southern coast of Ireland. The company has recently secured government funding for two further trials, one looking at long-term use of the supplement in postmenopausal women, which it hopes will support the recent findings.
Calcium supplements are widely recommended to help prevent and manage osteoporosis, a bone-wasting disease that affects postmenopausal women in particular. Worldwide, the lifetime risk for a woman to have an osteoporotic fracture is 30-40 per cent, according to the Internaional Osteoporosis Foundation, and in the next 50 years, the number of hip fractures for both men and women will more than double.
The new trial, presented at FASEB in Washington, US last month, was carried out by John Zenk and colleagues at the Minnesota Applied Research Center. Twelve pre-menopausal women were given a single, oral dose of each treatment. Blood was analysed during the 12-hour study period and a urine sample taken at the end.
Marigot, sister company of Celtic Sea Minerals, claims that its Aquamin does not have the same chalky taste often found when adding calcium to food products. It also contains a variety of other minerals found naturally in the dead seaweed, including magnesium and some boron, copper and zinc.
One of the few plant-based calcium sources, Aquamin is a long way off from competing with calcium carbonates on the market. However it has proved popular in Asian markets where consumers already know the benefits of seaweed and are keen to market its natural source.
It is also present in a number of European markets - France, the Netherlands, Scandinavia, as well as Ireland - in foods as diverse as bread, soymilk and supplements, while in the US, it is even used in a 'wellness' tea.
Marigot is looking for a further presence in southern Europe and also developing new combination products, such as CalciLife, launched in the US last year, and combining Aquamin with short-chain fructo-oligosaccharides for better absorption and benefits to gut health.
"We are will be carrying out some research into pain relief too and looking at wider applications for this ingredient. We would like to be able to present ourselves as a bone health company," said R&D manager Dr Susan Lawlor.