Effect of seaweed ( extract) on blood glucose and insulin level on prediabetic patients: A double-blind randomized controlled trial.

To investigate the effect of polyphenolic-rich seaweed extract () on postprandial blood glucose (PPBG) and postprandial insulin level (PPIL) as well as investigating any associated side effects related to the study intervention in 20 prediabetic patients in Saudi Arabia. The double-blind, randomized-controlled trial was conducted from November 2020 to April 2021 in Riyadh, in 20 prediabetic patients with no other health complications. Subjects were given 600 mg of seaweed extract in a single dose for acute effect investigation. PPBG and PPIL were measured immediately at intervals of 30, 60, 90, and 120 min following 75 g of carbohydrate consumption, iAUC and peak concentration were calculated accordingly. Insignificant differences were shown for PPBG levels between study groups at intervals of 30 and 60 min ( > .05). However, PPBG results were significantly lower in the intervention group compared to placebo of 90 and 120 min after carbohydrate (75 g) consumption. The mean (SD) of PPBG in the seaweed group at 90 and 120 min was 108.1 (±8.9) and 101.3 (±8.7), respectively, compared to the placebo group at 90 and 120 min with a mean of 122.2 (±16.9) and 112.9 (±12.1), respectively ( value at 90 min = 0.032) and ( value at 120 min = 0.024). iAUC of PPBG shows no significant differences between the study groups ( > .05). There was no significant difference in PPIL between study groups at all study measurements ( > .05). Discomfort symptoms were similar between study groups ( > .05). This study indicated that a single dose of 600 mg of E. cava extract has a lowering effect on postprandial blood glucose with no associated side effects. Further research should investigate the glycemic modulating effects of marine algal extracts in the long-term investigation.