Nutritional risk factors for SARS-CoV-2 infection: a prospective study within the NutriNet-Santé cohort.

BACKGROUND: Nutritional factors are essential for the functioning of the immune system and could therefore play a role in COVID-19 but evidence is needed. Our objective was to study the associations between diet and the risk of SARS-CoV-2 infection in a large population-based sample. METHODS: Our analyses were conducted in the French prospective NutriNet-Santé cohort study (2009-2020). Seroprevalence of anti-SARS-CoV-2 antibodies was assessed by ELISA on dried blood spots. Dietary intakes were derived from repeated 24 h dietary records (at least 6) in the two years preceding the start of the COVID-19 pandemic in France (February 2020). Multi-adjusted logistic regression models were computed. RESULTS: A total of 7766 adults (70.3% women, mean age: 60.3 years) were included, among which 311 were positive for anti-SARS-CoV-2 antibodies. Dietary intakes of vitamin C (OR for 1 SD=0.86 (0.75-0.98), P=0.02), vitamin B9 (OR=0.84 (0.72-0.98), P=0.02), vitamin K (OR=0.86 (0.74-0.99), P=0.04), fibers (OR=0.84 (0.72-0.98), P=0.02), and fruit and vegetables (OR=0.85 (0.74-0.97), P=0.02) were associated to a decreased probability of SARS-CoV-2 infection while dietary intakes of calcium (OR=1.16 (1.01-1.35), P=0.04) and dairy products (OR=1.19 (1.06-1.33), P=0.002) associated to increased odds. No association was detected with other food groups or nutrients or with the overall diet quality. CONCLUSIONS: Higher dietary intakes of fruit and vegetables and, consistently, of vitamin C, folate, vitamin K and fibers were associated with a lower susceptibility to SARS-CoV-2 infection. Beyond its established role in the prevention of non-communicable diseases, diet could therefore also contribute to prevent some infectious diseases such as COVID-19.

Effect of a new graphically modified Nutri-Score on the objective understanding of foods' nutrient profile and ultraprocessing: a randomised controlled trial.

Introduction: When considering health-related impacts of foods, nutrient profile and (ultra)processing are two complementary dimensions. The Nutri-Score informs on the nutrient profile dimension. Recently, mounting evidence linked ultraprocessed food consumption to various adverse health outcomes, independently of their nutrient profile. To inform consumers about each of these health-related dimensions of food, we tested, in a randomised controlled trial, if a graphically modified version 'Nutri-Score V.2.0', including a black 'ultraprocessed' banner, would improve the capacity of consumers to rank products according to their nutrient profile and to detect those ultra-processed, compared with a no-label situation. Methods: 21 159 participants included in the NutriNet-Santé web-cohort were randomly assigned to a control arm (no front-of-pack label) or an experimental arm (Nutri-Score 2.0) and were presented an online questionnaire with three sets of food products (cookies, breakfast cereals and ready-to-eat meals) to rank according to nutrient profile and to identify ultraprocessed foods. The primary outcome was objective understanding of nutrient profile and ultraprocessing, represented by a score of correct answers. Secondary outcomes were purchasing intentions and the healthiest-perceived product. Multinomial logistic regressions were performed. Results: The Nutri-Score V.2.0 increased the objective understanding of both the nutrient profile dimension (OR highest vs lowest score category=29.0 (23.4-35.9), p<0.001) and the ultraprocessing dimension (OR=174.3 (151.4-200.5), p<0.001). Trends were similar for cookies, breakfast cereals and ready-to-eat meals. The Nutri-Score V.2.0 had a positive effect on purchasing intentions and on the products perceived as the healthiest. Conclusion: This randomised controlled trial demonstrates the interest of a front-of-pack label combining the Nutri-Score (informing on the nutrient profile dimension) with an additional graphic mention, indicating when the food is ultraprocessed, compared with a no-label situation. Our results show that a combined label enabled participants to independently understand these two complementary dimensions of foods. Trial registration number: NCT05610930.

Association of SARS-CoV-2 infection with physical activity domains and types.

Lockdown imposed in the early phase of the SARS-CoV-2 outbreak represented a specific setting where activity was restricted but still possible. The aim was to investigate the cross-sectional associations between physical activity (PA) and SARS-CoV-2 infection in a French population-based cohort. Participants completed a PA questionnaire. PA was classified into: (i) total PA; (ii) aerobic PA by intensity; (iii) strengthening PA; (iv) PA by domain and type; and (vii) by location. Sedentary time was also recorded. Seroprevalence of anti-SARS-CoV-2 antibodies was assessed. Multivariable logistic regression models controlling for sociodemographic, lifestyle, anthropometric data, health status, and adherence to recommended protective anti-SARS-CoV-2 behaviours were computed. From 22,165 participants included, 21,074 (95.1%) and 1091 (4.9%) had a negative and positive ELISA-S test result, respectively. Total PA, vigorous PA, leisure-time PA, household PA, outdoor PA and indoor PA were all associated with lower probability of SARS-CoV-2 infection. Observations made in such a setting shed light on PA possibilities in a context of restricted mobility, where the health benefits of PA should not be overlooked. Along with already well-established benefits of PA for non-communicable disease prevention, these findings provide additional evidence for policies promoting all types of PA as a lever for population health.

Aortic wave reflection in women and men.

Augmentation index (AIx), a marker of the number of aortic wave reflections (AWRs), is influenced not only by the magnitude of incident and reflected pressure waves but also by the time of return. A new triangulation method has been developed, enabling us to better quantify AWRs and to determine their sex differences, which may relate to body size or pulse pressure (PP) amplification, measured from the brachial PP-to-carotid PP (B/C) ratio. With the use of pulse wave analysis, AWRs were evaluated in 51 women and 72 men treated for hypertension and studied in relationship to age, blood pressure, and pulse wave velocity. When women were compared with men, AIx (expressed in %PP and adjusted to heart rate) was significantly higher, together with a significant decrease of the B/C ratio and an increase of the reflection magnitude and of the amplitude (but not the timing) of the backward pressure wave. The significance of the amplitude difference between men and women was enhanced after an adjustment to heart rate or pulse wave velocity but was abolished after an adjustment to body height or the B/C ratio. In the overall population, AIx and the reflection magnitude index were positively (r(2) = 0.39) and independently associated, after excluding confounding factors such as drug treatment. In conclusion, when compared with men, women treated for hypertension have increased AIx, related to the increased amplitude, and not timing, of backward pressure waves. This finding relates to sex differences in body size and mostly brachial-carotid PP amplification, a parameter highly related to the sex difference of cardiovascular risk.