Associations of dietary intake on biological markers of inflammation in children and adolescents: A systematic review

Background: In children and adolescents, chronic low-grade inflammation has been implicated in the pathogenesis of co- and multi-morbid conditions to mental health disorders. Diet quality is a potential mechanism of action that can exacerbate or ameliorate low-grade inflammation; however, the exact way dietary intake can regulate the immune response in children and adolescents is still to be fully understood. Methods: Studies that measured dietary intake (patterns of diet, indices, food groups, nutrients) and any inflammatory biomarkers in children and adolescents aged 2 to19 years and published until November 2020 were included in this systematic review, and were selected in line with PRISMA guidelines through the following databases: Academic Search Complete, CINAHL, Global Health, Medline COMPLETE andWeb of Science-Core Collection. A total of 53 articles were identified. Results: Results show that adequate adherence to healthful dietary patterns such as the Mediterranean diet, or food groups such as vegetables and fruit, or macro/micro nutrients such as fibre or vitamin C and E, are associated with decreased levels of pro-inflammatory biomarkers, mainly c-reactive protein (CRP), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α), whereas adherence to aWestern dietary pattern, as well as intake of food groups such as added sugars, macro-nutrients such as saturated fatty acids or ultra-processed foods, is associated with higher levels of the same pro-inflammatory biomarkers. Conclusions: This is the first systematic review examining dietary intake and biological markers of inflammation in both children and adolescents. A good quality diet, high in vegetable and fruit intake, wholegrains, fibre and healthy fats ameliorates low-grade inflammation, and therefore represents a promising therapeutic approach, as well as an important element for disease prevention in both children and adolescents.
A.B. and C.M.P. are funded by the UK Medical Research Council (grants MR/L014815/1, MR/J002739/1and MR/N029488/1), the European Commission Horizon 2020 (grant SC1-BHC-01- 2019) and the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London; they have also received research funding from Johnson and Johnson for research on depression and inflammation, but this paper is independent from this funding. In addition, C.M.P. is funded by the Wellcome Trust strategy award to the Neuroimmunology of Mood Disorders and Alzheimer’s Disease (NIMA) Consortium (104025), which is also funded by Janssen, GlaxoSmithKline, Lundbeck and Pfizer, but, again, this paper is independent from this funding.