Background: To assess the nutraceutical effects of twice/daily intake of kiwifruit on periodontal parameters and systemic health before and after initial periodontal treatment (IPT). Methods: At baseline, participants were randomly assigned to test and control group, and either consumed two kiwifruits/day for 5 months or no kiwifruit. In the first 2 months, no periodontal treatment was delivered (2 M). Subsequently, a session of full-mouth IPT within 24 hours was performed. Participants were then re-assessed after 3 months (5 M). Blood samples, evaluating systemic biomarkers and vital signs, were also collected atbaseline, 2 M, and 5 M. Results: Groups were balanced at baseline. At 2 M no within-groups differences could be detected for any parameter but the bleeding score, which decreased significantly in the kiwifruit group by 6.67% ± 11.90% (P < 0.01). Comparison of test and control group showed that 2 months of kiwifruit consumption resulted in significant lower values of bleeding, plaque, and attachment loss. After IPT both groups demonstrated substantial significant clinical benefits however the control group showed significant greater reductions of bleeding, plaque and attachment loss than the test group. Systemic biomarkers and vital signs did not show clinically relevant differences between test and control group. Conclusions: Kiwifruit consumption reduces gingival inflammation despite the lack of any periodontal instrumentation or patient's behavioral changes. No adjunctive effect to periodontal treatment of dietary intake of kiwifruit was noted. (NCT NCT03084484).