The lockdowns resulting from the first wave of the COVID-19 pandemic impacted deeply on all life activities, including diet. We performed a systematic review to investigate changes in food intake, eating behaviours and diet quality during lockdown as compared to before. A literature search was performed using three electronic databases from inception until June 13, 2021. Observational studies evaluating changes in general populations during the COVID-19 pandemic lockdown were eligible. Out of 1,963 studies achieved from the search strategy, 95 met inclusion criteria (85 on adults, 10 on children/adolescents), and the majority were of high quality (72.6%). Most of the studies were web-based surveys using convenience sampling, mainly focused on variations in the consumption of foods and eating behaviours during lockdown, whereas only 15 studies analysed diet quality through dietary indices. On the basis of the definition of a healthful diet as reflected by a traditional Mediterranean diet, an increase in recommended foods such as fruit and vegetables, legumes, cereals and olive oil was observed, although a sharp decrease in fish intake and an increase in dairy products were documented. Accordingly, a reduction in foods that should be eaten less frequently was reported, namely, red and processed meat. However, a higher consumption of unhealthy foods (e.g., snacks and sweets) was also observed. Results indicated improved diet quality in Europe, especially among Mediterranean countries, with the exception of France, while a switching to poor nutrient patterns was observed in Colombia and Saudi Arabia. Analyses of eating behaviours suggest an increase in food intake, number of daily meals and snacking. In conclusion, changes in intake of major food groups, apart from fish intake, were in line with the definition of a traditional Mediterranean diet, indicating a consistent moderate improvement of dietary habits worldwide. This review protocol was registered at https://www.crd.york.ac.uk/prospero/ as CRD42020225292.

Household income in 2019 (EUR/y) ≤10.000 >10.000≤25.000 >25.000≤40.000 >40.000≤60.000 >60.000≤100.000 >100.000 Refused/I do not know Housing tenure Rent 1 dwelling ownership > 1 dwelling ownership Refused/I do not know Number of rooms in the house (bathrooms and additional rooms excluded) lockdown? (multiple choice) Blood pressure medications Cholesterol medications Diabetes drugs Anti-cancer drugs Corticosteroids Thyroid medications Anti-inflammatory drugs Anxiolytics Antidepressants Immunomodulators None Refused/I do not know Did you get flu vaccination last autumn (2019)? Yes/No/Refused/I do not know Did you get anti pneumococcal vaccine last autumn (2019)? Yes/No/Refused/I do not know Moli-LOCK Study Investigators

For decades, (poly)phenols have been linked to cardiometabolic health, but population heterogeneity limits their apparent efficacy and the development of tailored, practical protocols in dietary interventions. This heterogeneity is likely determined by the existence of different metabotypes, sub-populations of individuals metabolizing some classes of (poly)phenols differently. The gut microbiota plays a major role in this process. The impact of microbiota-related phenolic metabotypes on cardiometabolic health is becoming evident, although the picture is still incomplete, and data are absent for some classes of (poly)phenols. The lack of a complete understanding of the main microbial actors involved in the process complicates the picture. Elucidation of the mechanisms behind phenolic metabotypes requires novel experimental designs that can dissect the inter-individual variability. This paper, in addition to providing an overview on the current state-of-the-art, proposes wider metabotyping approaches as a means of paving the way towards effective personalized nutrition with dietary (poly)phenols.

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Objectives Evidence shows that bioactive (poly)phenols are pivotal in the prevention of chronic diseases, in particular in cardiometabolic health. However, the inter-individual variability existing in their bioavailability and physiological response can impact their true efficacy. Individuals showing similar metabolic profiles for specific (poly)phenols can be clustered into phenolic metabotypes, while comprehensive phenolic metabolic profiles derived from main dietary (poly)phenols could be referred to as “aggregate phenolic metabotypes”. The main aim of the study is to identify aggregate phenolic metabotypes and the determinants related to their formation. Methods An intervention study is carried out on 300 healthy volunteers (18–74 y) which are asked to provide information on dietary habits, smoking, physical activity, sleeping, anthropometric measures, health status, and biological samples. Subjects undergo a standardised oral (poly)phenol challenge test consisting in an acute supplementation of several classes of dietary (poly)phenols. Urine samples collected during the following 24h are analysed through UPLC-IMS-HRMS to assess the individual urinary excretion of phenolic metabolites, allowing aggregate metabotype clustering. Blood samples are analysed to determine common cardiometabolic health biomarkers, and buffy coat processed to isolate peripheral blood mononuclear cells (PBMCs) used for whole-genome genotyping. Transcriptomic signatures in PBMCs are also assessed. Gut microbiota composition will be profiled by shallow shotgun metagenomics. Cardiometabolic risk scores are also computed. Predictive models will be used to assess the determinants of inter-individual variation in (poly)phenol metabolism, providing indications in the cardiometabolic health status of each individual. Results Preliminary results are expected to be available for mid-2023. Conclusions Metabotyping according to the metabolism of the whole set of dietary (poly)phenols may thus represent a promising attempt for cardiometabolic health promotion through personalised nutrition initiatives. Funding Sources This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme.