This randomized, controlled study evaluated among 86 children aged 4 to 5 years, the effects of daily supplementation with 1.76 g of roasted nori compared to no supplementation during 10 weeks. Blood pressure was measured before and after supplementation.

Results showed that after 10 weeks, in boys changes in systolic blood pressure were -8.29 mmHg in the intervention group and +0.50 mmHg in the control group (p = 0.051). Changes in diastolic blood pressure were -6.77 mmHg in the intervention group and -0.05 mmHg in the control group (p = 0.031). In girls, no difference in blood pressure changes was found between the intervention and control groups.

In conclusion, Nori intake lowered diastolic blood pressure level in boys and tend to decrease systolic blood pressure. No effects were observed in girls.

Wada K, Tsuji M, Nakamura K, et al. Effect of dietary nori (dried laver) on blood pressure in young Japanese children: an intervention study [published online ahead of print, 2020 Mar 21]. J Epidemiol. 2020;10.2188/jea.JE20190176. doi:10.2188/jea.JE20190176