Search

BACKGROUND: Early time-restricted feeding (eTRF) is a new dietary strategy, involving extended fasting (≥14h) from mid- afternoon onwards with or without calorie restriction. Most of the published studies indicate controversial effects on several glycemic markers. AIM : To evaluate the effect of non-calorie restricted eTRF on the glycemic profile of adults. METHOD: this systematic review was designed according to PRISMA guidelines. Pubmed/ Medline, the Cochrane library and EBSCO electronic databases were systematically searched for eligible clinical trials. Studies with eTRF or with daily fasting regimens that presented all the characteristics of eTRF were selected and compared with regular diet schedules or delayed time-restricted feeding. Blood glucose and insulin markers were extracted from each study as the main outcome measures. RESULTS: Five articles including 67 adult subjects in total were selected. The period of intervention varied between 3 days to 5 weeks. Three of the included studies were diet- controlled for weight maintenance, whereas the other two studies allowed for free living. Quality assessment identified two studies of low and three studies of high risk of bias. two studies showed clear positive effects of eTRF on both glucose and insulin markers, including fasting glucose levels, muscle glucose intake, glucose iAUC responses insulin levels, and insulin resistance (p<0.05). Two other studies showed beneficial effects on glucose markers only (fasting glucose, 24h mean glucose levels, and iAUC responses, p<0.05) and the fifth study showed positive effects on insulin markers only (insulin resistance, p<0.05). CONCLUSIONS: eTRF seems to have positive effects on the glycemic profile mainly in healthy individuals with normal BMI. However, other factors should also be taken into account to address overweight, obese, and prediabetic individuals. Further research is required to clarify better the effectiveness of eTRF among individuals with different characteristics.

In previous studies, we reported that neonates of women with gestational diabetes mellitus (GDM) have reduced blood levels of arachidonic acid (AA) and docosahexaenoic acid (DHA) that were unrelated to maternal status. Since both AA and DHA are selectively transferred from maternal to fetal circulation by the placenta, we have investigated whether the FA composition of the placenta is altered by GDM. Thirty-six women, 11 with and 25 without GDM, were recruited from Newham General Hospital, London. The women with GDM had higher levels of di-homo-gamma-linolenic (P < 0.05), docosatetraenoic (n-6 DTA; P< 0.0001), docosapentaenoic n-6 (P< 0.005), total n-6 (P < 0.005), docosapentaenoic (n-3 DPA; P < 0.005), and total n-3 (P < 0.01) FA, as well as higher levels of AA (P < 0.05) and DHA (P < 0.01), in placental choline phosphoglycerides (CPG) compared with the healthy women who served as controls. Similarly, the women with GDM had elevated n-6 DTA (P < 0.005), AA, total n-6 metabolites (P < 0.05), DHA, total n-3 metabolites, and total n-3 FA (P < 0.005) in ethanolamine phosphoglycerides (EPG). In contrast to CPG and EPG, the placental TG of the women with GDM had higher linoleic acid (P< 0.05) and lower AA, n-6 metabolites, and n-3 DPA (P < 0.01). The placenta is devoid of desaturase activity, and it is thought to be reliant on maternal circulation for both AA and DHA. Hence, the enhanced levels of the two FA in the placenta of the GDM group suggests that these FA are taken up from the maternal circulation and retained after esterification into phosphoglycerides instead of being transferred to the fetus. Further study is needed to elucidate the mechanism involved and the effect of the phenomenon on postnatal growth and development of the offspring.

The aim of this study was to determine whether the high concentration of arachidonic acid (AA) in term placentae accumulates during pregnancy or is an inherent characteristic of placental lipids. We investigated the lipid content and fatty acid composition of the human placental phospholipids at 2 gestational periods, early in pregnancy (8-14 wk, n = 48) and at term (38-41 wk of gestation, n = 19). The subjects were healthy, normotensive, and free of medical and obstetric complications. The lipid concentration of placentae increased from 0.8% in early gestation to 1.4% at term (P < 0.0001). The mean proportions of AA were lower in the choline (P < 0.05), inositol (P < 0.0001), and ethanolamine (P < 0.0001) phosphoglycerides of the term compared with the early placenta. In contrast, the proportions of the immediate precursor of AA, dihomo-gamma-linolenic acid (DGLA), were higher in the term placenta, particularly in the inositol and serine phosphoglycerides (P < 0.0001). In sphingomyelin, the percentage of lignoceric acid was increased and that of nervonic acid was reduced at term (P < 0.01). The dominance of AA, particularly in the early placenta, suggests that it has an important role for placental development, i.e., organogenesis and vascularization. There was no evidence of an accumulation of AA in the placenta toward term, which might be a trigger for parturition. In contrast, the increased proportion of DGLA (precursor of the vasorelaxant and anticoagulant prostaglandin E(1)) at term is more consistent with a profile favoring optimal blood flow to nourish the fetal growth spurt.