Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924/2006. This opinion addresses the scientific substantiation of health claims in relation to sodium alginate and reduction of post-prandial glycaemic responses. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders. The food constituent that is the subject of the health claim is “sodium alginate and Ascophyllum nodosum”. From the references provided, the Panel assumes that the food constituent that is the subject of the health claim is sodium alginate. The Panel considers that sodium alginate with an M/G ratio of 1.50 is sufficiently characterised in relation to the claimed effect. The claimed effect is “alginate can reduce the activity of digestive enzymes and reduce glucose absorption”. The target population is assumed to be subjects who wish to reduce their post-prandial glycaemic responses. The Panel considers that the reduction of post-prandial glycaemic responses (as long as post-prandial insulinaemic responses are not disproportionally increased) may be a beneficial physiological effect. In weighing the evidence, the Panel took into account that the one human intervention study provided from which conclusions could be drawn for the scientific substantiation of the claim did not show a reduction in post-prandial glycaemic responses without a disproportionate increase in post-prandial insulinaemic responses following consumption of sodium alginate. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of sodium alginate and the reduction of post-prandial glycaemic responses without disproportionally increasing post-prandial insulinaemic responses.