Prolonged administration of Ascophyllum nodosum to healthy human volunteers and cardiovascular risk

Introduction Edible algae, rich in biologically active components, may influence glycaemic control, lower blood lipids and increase antioxidant activities. The aim of this study was to evaluate the effect of prolonged supplementation with an extract of the brown edible seaweed Ascophyllum nodosum on anthropometric indexes and biomarkers of metabolic risk for cardiovascular disease in human volunteers. Methods The study was a randomised, placebo-controlled, double-blind trial, following a cross-over design, in healthy adult subjects. After a 1-week run-in period on a controlled diet, two capsules of algae (Algeafood Phyto, Algea AS, Norway), each containing 900 mg algae and 175 μg iodine, or placebo, were given daily for 6 weeks, with 2 weeks wash-out between treatments. Anthropometric, clinical and laboratory parameters, and inflammation, haemostatic and organ function markers were measured at baseline and after 3 and 6 weeks of supplementation. Results and discussion The trial was completed by 43 healthy subjects (24 women), aged 21–63 years. No changes in any of the parameters were reported at 3 weeks, but there was a significant reduction of platelet count ( p <0.026) after algae supplementation, which was reversed at 6 weeks. After 6 weeks of algae supplementation, a significant decrease in both body weight and body mass index (BMI) occurred, with no difference between the treatment and placebo groups. Triglyceride (TG) levels were lowered by 5% after 6 weeks of active treatment: an effect significantly different from that observed in the placebo group. A non-significant trend to decreased total cholesterol and low-density lipoprotein and to increased high-density lipoprotein was observed in both supplementation groups. Tumour necrosis factor-α was significantly increased in the placebo group, but not in the active group, while adiponectin was significantly increased in both groups, with no difference between them. All other parameters were unchanged, including organ function variables; in particular, no negative effects on thyroid function were observed, in relation to the iodine content of the algae extract. Conclusions In conclusion, chronic algae supplementation in healthy human subjects induced lowering of TG levels and probably of BMI. To confirm these effects and make dietary recommendations for subjects with high BMI or TG levels, further studies are warranted.