The oral und systemic health risks of sugar consumption: an umbrella review

Abstract Objective The recommendation of free sugar reduction in dental practice is mostly given with regard to caries prevention but has also further health impacts. This umbrella review aimed to comprehensively display the shared health consequences of sugar consumption in both oral and general health. Materials and methods Within an umbrella review, two independent reviewers identified and analysed systematic reviews examining free sugar consumption alone or as a part of dietary patterns and its association to described diseases in three databases (Epistemonikos, Pubmed, Cochrane Library). Electronic databases were searched up to March 2026, findings were synthesised narratively. Risk of bias was assessed using AMSTAR-2. Results The literature search identified 10,593 articles, of which 633 were further assessed for eligibility. Finally, 228 articles were included after full-text analysis. Results showed that sugar intake was consistently associated with increased risks of 18 generalised negative health outcomes. Strongest evidence was found for type 2 diabetes, obesity, cardiovascular and all-cause mortality, oral diseases, irritable bowel syndrome, and cognitive disorders. Furthermore, a positive association was found between excessive sugar consumption and cancer, non-alcoholic fatty liver disease, kidney disease, gout, asthma, poor sleep, reduced bone density, mood disorders, telomere shortening, and fertility impairments. AMSTAR-2 showed that most reviews had low or critically low methodological quality, while about one third demonstrated moderate to high confidence. Most studies (68%) investigated sugar in form of sugar-sweetened beverages. Conclusions Within the limitations of this umbrella review, available evidence indicates that avoiding free sugar intake contributes to both reduced chronic disease burden and improved oral health. Against this background, avoiding free sugar, as recommended by dentists, is a key shared health factor that should be emphasized in the context of caries, periodontal disease, and in terms of general primary prevention. Clinical relevance Dental advised and assisted sugar reduction is an important preventive measure not only for oral health but also for several general health outcomes. After synthesizing and evaluating the available systematic reviews, this study highlights the crucial need to reduce sugar consumption as an important factor in improving both systemic and oral health. Systematic review registration The systematic review was registered in the international register for systematic reviews Prospero. Systematic review registration CRD42023380458.