Changes in PYY and gastric emptying across the phases of the menstrual cycle and the influence of the ovarian hormones

Abstract

Nutrition-related studies avoid the participation of pre-menopausal women due to the potential effect of the menstrual cycle (MC) on their appetite regulation. It is generally accepted that women increase their energy intake during the luteal phase (LPh) compared to the follicular (FPh), however what happens in the menstrual phase (MPh) and how this might be regulated remains uncertain. Although some research indicates changes in the gastric emptying (GE) velocity, whether PYY is affected by the MC phase, remains unknown. The aim of this study was to assess whether eating the same breakfast in each of the three MC phases would change the GE time, the PYY response and post-prandial satiety such that they might affect subsequent food intake. Furthermore, the aim was to associate any potential differences to the fluctuations in estradiol (E) and progesterone (P) within a MC. Nine naturally cycling women attended to the laboratory to consume a standardised breakfast on three occasions, each of them representing one of the MC phases. Breath samples to measure GE time, plasma samples to quantify PYY levels and hunger scores were collected for a total of 4 h after which food intake was assessed by an ad-libitum buffet lunch. GE and PYY levels changed significantly across the phases of the MC (p < 0.05). GE was correlated to P and E-P ratio (r = -0.5 and 0.4, respectively). To conclude, the appetite regulators PYY and GE time change depending upon the MC phases with GE time associated with the ovarian hormone levels which suggests the necessity of controlling the MC phase in studies looking at the appetite response.

The Effect of Acute Hypohydration on Indicators of Glycemic Regulation, Appetite, Metabolism and Stress: A Systematic Review and Meta-Analysis

“…Among studies looking at appetite regulation, some referred to the difficulty to control for the complex interactions between menstrual cycle hormones and appetite independent of the influence of menstrual cycle on fluid regulatory hormones. For example, both leptin and PYY have been shown to change significantly across the menstrual cycle [114,115], while changes in ghrelin seem to occur in females with menstrual cycle disturbances [116]. Thus, it is possible that changes in hormone levels in some of the studies included in this review with female participants could have been confounded by variable menstrual cycle stages among participants.…”

The acute effects of baobab fruit (Adansonia digitata) on satiety in healthy adults

“…A limitation was that menstrual cycle phase was not controlled for in the current study. Although research from our lab has failed to show differences in food intake and perceived food intake from VAS across the phases of the menstrual cycle (Campolier et al, 2016), earlier studies show conflicting results (Dye and Blundell, 1997). Therefore, had it been controlled for perhaps trends in food intake would have been detected.…”

Perioperative fasting and feeding in adults, obstetric, paediatric and bariatric population: Practice Guidelines from the Indian Society of Anaesthesiologists

“…The categorisation of food items by the survey into heavy meals, light meals and clear liquids was reviewed by an experienced dietician after referring to the available evidence [ Appendix 1 – Appendix 3 ]. [ 20 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 ] The classification was revised by the dietician based on the duration of emptying of the stomach contents as clear liquids, non-clear liquids, light meal and heavy meal [ Table 2 ].…”