Objectives <p>The aim of this systematic review is to evaluate evidence relating to whether adopting a diet, associated with improved outcomes for chronic systemic diseases with an inflammatory component, can improve periodontal parameters in patients with periodontal diseases.</p> Data sources <p>Electronic databases and one platform were systematically searched; Medline, Embase, Web of Science and the Cochrane Library including references of relevant studies.</p> Data selection and extraction <p>1220 studies were identified of which 9 studies were eligible; 4 RCT’s, 1 controlled trial and 4 observational cohort studies</p> Data synthesis <p>8 out of 9 studies found improved periodontal parameters associated with a diet that was low in refined carbohydrates, low in saturated fats, high in fibre and high in nutrition but the studies were low to medium quality of evidence and the diets, method of recording the diets and periodontal parameters varied between the studies as did the study duration and age of participants.</p> Conclusion <p>Current evidence supports the hypothesis that adopting a healthy diet has the potential to positively impact periodontal parameters in patients with periodontal diseases, particularly in the older population but the effects may be negated by confounding factors such as smoking. 9 studies were included in the review which were rated moderate or low quality of evidence.</p>