Chrononutrition in the context of Ramadan: Potential implications

The effect of Ramadan intermittent fasting on anthropometric, hormonal, metabolic, inflammatory, and oxidative stress markers in pre-and post-menopausal women: a prospective cohort of Saudi women

Background

The menopausal transition significantly affects cardiometabolic health, primarily due to changes in reproductive hormones, particularly decreased estrogen levels and relative androgen excess. Adult Muslim women, both pre-and post-menopausal, are mandated to observe Ramadan intermittent fasting (RIF) every year. Therefore, the current study was designed to investigate RIF's effects on pre-menopausal (PRE-M) and post-menopausal (POST-M) healthy women's cardiometabolic health markers. This study further evaluated the relationship between tested markers and the participant's basic variables, such as BMI and body fatness. Due to differences in physiological and metabolic biomarkers between groups, RIF is likely to impact PRE-M and POST-M women differently.

Methods

This study included 62 healthy women (31 PRE-M, aged 21-42 years, and 31 POST-M, aged 43-68 years) who observed RIF. Anthropometrics, sex hormones, lipid profile, pro-inflammatory (TNF-α), anti-inflammatory (IL-10) cytokines, the oxidative stress markers malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GPx), and aging biomarker insulin-like growth factor-1 (IGF-1); all were tested 1 week before and at the fourth week of Ramadan.

Results

Body weight, BMI, waist circumference, body fat percentage (BFP), fat mass, fat mass index, triglycerides, and diastolic blood pressure significantly (p < 0.05) decreased at the end of Ramadan in both groups in comparison to the pre-fasting period. Contrarily, HDL, SOD, GPx, and IL-10 significantly (p < 0.05) increased in both groups. Estrogen levels significantly (p < 0.05) decreased in PRE-M women, whereas significantly (p < 0.05) increased in POST-M women. The progesterone levels, TAC, MDA, and IGF-1 remained unchanged in both groups. TNF-α significantly decreased in both groups, but the magnitude of reduction was higher in PRE-M women. Sex hormones and some metabolic biomarkers, especially in POST-M women, variably exhibited positive or negative relationships to BMI and BFP. RIF may influence the levels of estrogen, TNF-α, and IL-10 through improvements in metabolic health, reductions in body fat, activation of autophagy, modulation of immune responses, and changes in hormonal regulation.

Conclusion

The RIF was generally associated with improved anthropometric, metabolic, inflammatory, and oxidative stress markers in both PRE-M and POST-M healthy women. Adhering to healthy dietary and lifestyle guidelines by pre-and post-menopausal women during Ramadan may foster the health benefits gained.

Twenty-Four Hour Glucose Profiles and Glycemic Variability during Intermittent Religious Dry Fasting and Time-Restricted Eating in Subjects without Diabetes: A Preliminary Study

Intermittent religious fasting increases the risk of hypo- and hyperglycemia in individuals with diabetes, but its impact on those without diabetes has been poorly investigated. The aim of this preliminary study was to examine the effects of religious Bahá'í fasting (BF) on glycemic control and variability and compare these effects with time-restricted eating (TRE). In a three-arm randomized controlled trial, 16 subjects without diabetes were assigned to a BF, TRE, or control group. Continuous glucose monitoring and food intake documentation were conducted before and during the 19 days of the intervention, and the 24 h mean glucose and glycemic variability indices were assessed. The BF and TRE groups, but not the control group, markedly reduced the daily eating window while maintaining macronutrient composition. Only the BF group decreased caloric intake (-677.8 ± 357.6 kcal, p = 0.013), body weight (-1.92 ± 0.95 kg, p = 0.011), and BMI (-0.65 ± 0.28 kg, p = 0.006). Higher maximum glucose values were observed during BF in the within-group (+1.41 ± 1.04, p = 0.039) and between-group comparisons (BF vs. control: p = 0.010; TRE vs. BF: p = 0.022). However, there were no alterations of the 24 h mean glucose, intra- and inter-day glycemic variability indices in any group. The proportions of time above and below the range (70-180 mg/dL) remained unchanged. BF and TRE do not exhibit negative effects on glycemic control and variability in subjects without diabetes.

Meal timing and its role in obesity and associated diseases

Meal timing emerges as a crucial factor influencing metabolic health that can be explained by the tight interaction between the endogenous circadian clock and metabolic homeostasis. Mistimed food intake, such as delayed or nighttime consumption, leads to desynchronization of the internal circadian clock and is associated with an increased risk for obesity and associated metabolic disturbances such as type 2 diabetes and cardiovascular diseases. Conversely, meal timing aligned with cellular rhythms can optimize the performance of tissues and organs. In this review, we provide an overview of the metabolic effects of meal timing and discuss the underlying mechanisms. Additionally, we explore factors influencing meal timing, including internal determinants such as chronotype and genetics, as well as external influences like social factors, cultural aspects, and work schedules. This review could contribute to defining meal-timing-based recommendations for public health initiatives and developing guidelines for effective lifestyle modifications targeting the prevention and treatment of obesity and associated metabolic diseases. Furthermore, it sheds light on crucial factors that must be considered in the design of future food timing intervention trials.

Chrononutrition in cardiometabolic diseases: Current evidence and future perspectives

Chrononutrition is the field of nutritional science that investigates the relationship between food intake, timing of food intake, and their effects and influence on circadian rhythms and overall health. By aligning eating patterns with body's internal clock, optimisation of metabolic processes, improvements of various aspects of health can be achieved. Cardiovascular (CV) and metabolic diseases remain the leading cause of morbidity and mortality worldwide. Notably, in the US alone, approximately half of all cardiometabolic deaths are attributed to modifiable dietary factors, suggesting that dietary changes could result in dramatic increases in lifespan and its related quality of life. Social media have also a great impact on chrononutrition and their role cannot be neglected. The impact of social media on chrononutrition can be multifaceted: information dissemination, influence on eating habits, digital detox challenges, cultural influence and social jet lag. This special issue will provide novel insights and clarifications on chrononutrition, but also on additional controversial topics. The articles we selected should promote future preclinical and clinical studies to ultimately identify the most appropriate approaches to reduce the unacceptable high burden of CV and metabolic diseases.