Diet Quality and Risk of SARS-CoV-2 Infection or COVID-19: A Systematic Review of Observational Studies.

The COVID-19 pandemic highlighted the importance of healthy diets in the management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19. Evidence suggests the influence of diet and dietary patterns during post-COVID-19, and the impact of the COVID-19 pandemic on dietary habits and quality. However, limited evidence lies on the association between a healthy diet, and risk of SARS-CoV-2 infection or COVID-19. This study aimed to conduct a systematic review of observational studies to examine the association between diet quality, and the risk of SARS-CoV-2 infection or COVID-19 among adult populations. 6158 research articles from Scopus, EMBASE, PubMed, and MEDLINE databases were identified for eligibility. Only observational studies were included. Study quality was assessed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Thirteen studies were included (4 with SARS-CoV-2 infection and 9 with COVID-19 as the outcome); 3 were case-control, 3 were cross-sectional, and 7 were prospective studies. Adherence to Mediterranean diet was examined as exposure in 7 studies, and was associated with decreased risk of SARS-CoV-2 infection in 2 studies, with estimates varying from 12% to 22%, while COVID-19 risk or severity was found to be reduced in 3 studies with odds ratios (ORs) ranging from 36% to 77%. The Dietary Approaches to Stop Hypertension diet was inversely associated with COVID-19 hospitalization (OR: 0.19; 95% CI: 0.07, 0.55), whereas a healthy plant-based diet had an inverse association with both COVID-19 infection (hazard ratio [HR]: 0.91; 95% CI: 0.88, 0.94) and severity (HR: 0.59; 95% CI: 0.47, 0.74). Studies examining individual food groups generally found lower risk of infection or COVID-19 in association with larger dietary intakes of fruits, vegetables, and fiber. The overall findings of the observational studies in this review support the concept that nutritious diets might lower the risk of SARS-CoV-2 infection or COVID-19. This study was registered at PROSPERO as CRD42023397371.

Habitual adherence to a traditional Mediterranean diet and risk of SARS-CoV-2 infection and Coronavirus disease 2019 (COVID-19): a longitudinal analysis.

Evidence on habitual Mediterranean diet (MD) and risk of SARS-CoV-2 infection, and COVID-19 is limited. 1,520 participants from the Moli-sani Study (2017-2020) were tested during January-September 2021 and adherence to MD was ascertained through the Mediterranean Diet Score (MDS). SARS-CoV-2 infection cases were determined through serology, and previous clinical diagnosis of COVID-19 disease was self-reported. Results were presented as odd ratios (OR) with 95% confidence intervals (CI). The MDS was not associated with the likelihood of SARS-CoV-2 infection (OR= 0.94; 95% CI: 0.83-1.06) and COVID-19 (OR= 0.82; 95% CI: 0.62-1.10) diagnosis. High consumption of cereals was associated with lower odds of SARS-CoV-2 infection (OR = 0.91; 95% CI: 0.83-1.00; for each 25 g/d increase). Likelihood of having being diagnosed with COVID-19 disease decreased in association with increasing olive oil intake (OR= 0.10; 95% CI: 0.01-0.79; for each additional 10 g/d), moderate alcohol consumption (OR= 0.18; 95% CI: 0.04-0.82) and higher intakes of fruits and nuts (OR = 0.89; 95% CI: 0.79-0.99). Our findings emphasise the adoption and maintenance of a balanced MD as a key strategy to reduce the risk of future SARS-CoV-2 infections and COVID-19.

Is dietary macronutrient composition during pregnancy associated with offspring birth weight? An observational study.

There is lack of evidence on the differential impact of maternal macronutrient consumption: carbohydrates (CHO), fats and protein on birth weight. We investigated the association between maternal dietary macronutrient intakes and their sub-components such as saccharides and fatty acids and birth weight. This analyses included 1,196 women with singleton pregnancies who were part of the CAffeine and REproductive health study in Leeds, UK between 2003 and 2006. Women were interviewed in each trimester. Dietary information was collected twice using a 24-h dietary recall about 8-12 weeks and 13-27 weeks of gestation. Multiple linear regression models adjusted for alcohol and smoking in trimester 1, showed that each additional 10 g/d CHO consumption was associated with an increase of 4 g (95 % CI 1, 7; P=0·003) in birth weight. Conversely, an additional 10 g/d fat intake was associated with a lower birth weight of 8 g (95 % CI 0, 16; P=0·04) when we accounted for energy contributing macronutrients in each model, and maternal height, weight, parity, ethnicity, gestational age at delivery and sex of the baby. There was no evidence of an association between protein intake and birth weight. Maternal diet in trimester 2 suggested that higher intakes of glucose (10 g/d) and lactose (1 g/d) were both associated with higher birth weight of 52 g (95 % CI 4, 100; P=0·03) and 5 g (95 % CI 2, 7; P<0·001) respectively. These results show that dietary macronutrient composition during pregnancy is associated with birth weight outcomes. An appropriately balanced intake of dietary CHO and fat during pregnancy could support optimum birth weight.