Association between timing of food intake and adult acne in the NutriNet-Santé cohort

The role of diet in inflammatory skin conditions is receiving increasing attention (1–3) . However, despite mechanistic evidence from pre-clinical studies suggesting that feeding time alters the skin’s circadian clock and its functions (4,5) , the role of food intake timing in the etiology and severity of acne has been rarely explored in humans. This study aims to assess the association between timing and frequency of food intake, energy distribution and chrononutritional behavior patterns with lifetime occurrence and severity of acne in adults of a large French cohort. We used dietary, lifestyle and sociodemographic data from 27,411 adults (76% females, 48 years ±14) enrolled in the NutriNet-Santé (6) cohort between 2009 and 2018, who responded to the diet and skin questionnaire in 2018, and filled at least 3 24-H dietary records since inclusion in the study (mean= 23 records ±13). Associations between timing of first and last eating episodes of the day, number of eating occasions, nighttime fasting duration (NFD), eating jetlag, and percentage of energy intake after 5PM, and the odds of lifetime acne were evaluated using multi-adjusted logistic regression models. Associations between chrononutritional behavioral patterns, derived using principal component analysis (PCA), and the odds of lifetime acne were also explored. Multinomial logistic regressions were used in acne severity models, adjusted for key confounders, including diet quality. In the final sample, 12,903 participants (47.1%) reported experiencing at least one acne episode in their lifetime, and 1,057 reported having a current episode of moderate to severe acne. In fully adjusted models, a later last eating occasion (OR per 1hr-increase = 1.06 (1.02-1.10), P=0.0008), and the number of eating occasions (non-linear association: OR (> 6) vs (0-3) eating occasions = 1.38 (1.20-1.58) <0.0001) were associated with higher odds of lifetime acne. A chrononutritional pattern characterized by a later eating window was associated with higher odds of lifetime acne (OR for 1 SD increase= 1.06 (1.03-1.09) , P <0.0001), while a pattern characterized by prolonged NFD, and early last eating episode was associated with lower odds (OR= 0.94 (0.92-0.97), P<0.0001). In models exploring the severity of current acne episodes, the number of eating occasions was associated with mild (OR=1.08 (1.03-1.13), P = 0.0004), and moderate to severe acne (OR=1.05 (1.01-1.10), P=0.02) compared to those who never had acne. This study suggests a potential role of time and frequency of eating on acne in adults. Longitudinal and interventional studies are needed to confirm these associations, and the underlying mechanisms need to be further investigated.