Insulin responses following glucose administration in menstruating women

Impact of Physiological Fluctuations of Sex Hormones During the Menstrual Cycle on Glucose Metabolism and the Gut Microbiota

Diabetes mellitus is one of the most prevalent chronic diseases. Previous studies have shown differences in glucose metabolism between males and females. Moreover, difficulties in medication adherence have been reported in females with type 2 diabetes. These observations are believed to be caused by fluctuations in sex hormone concentrations during the menstrual cycle. Furthermore, gut microbiota is linked to female host metabolism and sex hormone production. Understanding the interactions between fluctuating hormone concentrations during the menstrual cycle, gut microbiota, and glucose metabolism in humans is significant because of the increasing prevalence of diabetes and the consequent need to expand preventive efforts. A literature search was performed to determine and summarize the existing evidence, deduce future research needs to maintain female health, and investigate the relationship between the physiological menstrual cycle and glucose metabolism. Studies from 1967 to 2020 have already examined the relationship between variations during the menstrual cycle and glucose metabolism in healthy female subjects using an oral-glucose tolerance test or intravenous glucose tolerance test. However, the overall number of studies is rather small and the results are contradictory, as some studies detected differences in glucose concentrations depending on the different cycle phases, whereas others did not. Some studies reported lower glucose levels in the follicular phase than in the luteal phase, whereas another study detected the opposite. Data on gut microbiota in relation to the menstrual cycle are limited. Conflicting results exist when examining the effect of hormonal contraceptives on the gut microbiota and changes in the course of the menstrual cycle. The results indicate that the menstrual cycle, especially fluctuating sex hormones, might impact the gut microbiota composition.The menstrual cycle may affect the gut microbiota composition and glucose metabolism. These results indicate that glucose tolerance may be the greatest in the follicular phase; however, further well-conducted studies are needed to support this assumption.

Association of inflammation biomarkers with food cravings and appetite changes across the menstrual cycle

IMPORTANCE

Premenstrual symptoms, including food cravings, are often a regular complaint among menstruating women. However, existing evidence regarding the biological mechanisms by which these food cravings occur remains unclear. Inflammation may play an essential role in the occurrence of these food cravings before menstruation.

OBJECTIVE

The purpose of the present study was to examine the associations between inflammatory markers and the risk of moderate/severe food cravings while accounting for changes in hormone levels and stress across the menstrual cycle.

DESIGN, SETTING, AND PARTICIPANTS

The BioCycle Study followed women (n = 259) aged 18-44 for two menstrual cycles. Food cravings (via questionnaire) were assessed up to four times per cycle. Each assessment corresponded to menses and mid-follicular, ovulation, and luteal phases of the menstrual cycle. A wide range of cytokine and chemokine levels (hsCRP, GCSF, GMCSF, IL-4, IL-6, RANTES, MIP1B, etc.) were assessed in blood samples collected at up to 8 visits per cycle, with visits timed using fertility monitors.

MAIN OUTCOMES AND MEASURES

Cravings for chocolate, sweets, salty, and other foods, and changes in appetite were determined to estimate the odds of moderate or severe cravings. Associations between inflammatory markers and risk of reporting a moderate/severe craving symptom at each cycle visit was determined using weighted generalized linear models (e.g., marginal structural models). Models were adjusted for age, BMI, and race, as well as time-varying covariates such as estradiol, stress, leptin, and total energy intake, and accounted for repeated measures (i.e., multiple cycles per woman). Both inflammatory markers and reports of cravings were modeled to account for variation at each visit.

RESULTS

An association between higher inflammatory biomarkers such as hsCRP, GCSF, GMCSF, IL-4, IL-6, RANTES, MIP, and increased risk of moderate/severe cravings were identified across the menstrual cycle all risk ratio>1, all CIs range 0.71-2.38. hsCRP retained statistical significance after false discovery rate correction with chocolate, sweet, and salty cravings, while GCSF, GMCSF, IL-6, and RANTES retained significance with chocolate and sweet cravings only.

CONCLUSION

and Relevance: The results suggest a potential role of inflammation in food cravings and appetite changes across the menstrual cycle.

Association of Inflammation Biomarkers with Food Cravings and Appetite Changes Across the Menstrual Cycle

Background

Premenstrual symptoms, including food cravings, are often a regular complaint among menstruating women. However, existing evidence regarding the biological mechanisms by which these food cravings occur remains unclear. Inflammation may play an essential role in the occurence of these food cravings before menstruation.

Purpose

The purpose of the present study was to examine the associations between inflammatory markers and the risk of moderate/severe food cravings while accounting for changes in hormone levels and stress across the menstrual cycle.

Methods

The BioCycle Study followed women (n=259) aged 18-44 for two menstrual cycles. Food cravings (via questionnaire) were assessed up to four times per cycle. Each assessment corresponded to menses and mid-follicular, ovulation, and luteal phases of the menstrual cycle. A wide range of cytokine and chemokine levels (hsCRP, GCSF, GMCSF, IL-4, IL-6, RANTES, MIP1B, etc.) were assessed in blood samples collected at up to 8 visits per cycle, with visits timed using fertility monitors. Cravings for chocolate, sweets, salty, and other foods, and changes in appetite were determined to estimate the odds of moderate or severe cravings. Associations between inflammatory markers and risk of reporting a moderate/severe craving symptom at each cycle visit was determined using weighted generalized linear models (e.g., marginal structural models). Models were adjusted for age, BMI, and race, as well as time-varying covariates such as estradiol, stress, leptin, and total energy intake, and accounted for repeated measures (i.e., multiple cycles per woman). Both inflammatory markers and reports of cravings were modeled to account for variation at each visit.

Results

An association between higher inflammatory biomarkers such as hsCRP, GCSF, GMCSF, IL-4, IL-6, RANTES, MIP1B, and increased risk of moderate/severe cravings were identified across the menstrual cycle |all risk ratio>0.8, all CIs range>0.7-0.9|. hsCRP retained statistical significance after false discovery rate correction with chocolate, sweet, and salty cravings, while GCSF, GMCSF, IL-6, and RANTES retained significance with chocolate and sweet cravings only.

Conclusion

The results suggest a potential role of inflammation in food cravings and appetite changes across the menstrual cycle.

Insulin sensitivity, food intake, and cravings with premenstrual syndrome: a pilot study

OBJECTIVE

The objective of this pilot study was to evaluate possible differences in insulin sensitivity, food intake, and cravings between the follicular and luteal phases of the menstrual cycle in women with premenstrual syndrome (PMS).

METHODS

Subjects were screened for PMS using the Penn Daily Symptom Rating (DSR) scale. Each subject had two overnight admissions (once in each cycle phase) to the Hospital of the University of Pennsylvania. They performed 3-day diet histories prior to each hospitalization. After admission, subjects received dinner and a snack, then were fasted until morning, when they underwent a frequently sampled intravenous glucose tolerance test (FSIGT). Insulin sensitivity was determined by Minimal Model analysis. Blinded analysis of diet histories and inpatient food intake was performed by a registered dietitian.

RESULTS

There was no difference found in insulin sensitivity between cycle phases (n = 7). There were also no differences in proportions of macronutrients or total kilocalories by cycle phase, despite a marked difference in food cravings between cycle phase, with increased food cravings noted in the luteal phase (p = 0.002). Total DSR symptom scores decreased from a mean of 186 (+/-29.0) in the luteal phase to 16.6 (+/-14.2) in the follicular phase. Women in this study consumed relatively high proportions of carbohydrates (55%-64%) in both cycle phases measured.

CONCLUSIONS

These findings reinforce the suggestion that although the symptom complaints of PMS are primarily confined to the luteal phase, the neuroendocrine background for this disorder may be consistent across menstrual cycle phases.

Menstrual cycle effects on insulin sensitivity in women with type 1 diabetes: a pilot study

BACKGROUND

Many women complain of difficulty maintaining euglycemia during the luteal phase of the menstrual cycle. This pilot study's objective was to evaluate possible differences in insulin sensitivity between follicular and luteal phases in women with type 1 diabetes.

METHODS

Women using insulin infusion pumps (n = 5, mean age 29.2 +/- 10.9 years, mean body mass index 24 +/- 1.8 kg/m(2)) underwent frequently sampled intravenous glucose tolerance tests during each cycle phase. Insulin sensitivity and glucose effectiveness were determined by Minimal Model analysis.

RESULTS

Non-insulin-mediated glucose disposal increased during the luteal phase (0.009 +/- 0.004 min(1)) versus the follicular phase (0.005 +/- 0.003 min(1)) (P < 0.05). Although no significant differences were found in mean insulin sensitivity between follicular (0.76 +/- 0.27 x 10(4)/min(1) /microU/mL) and luteal phase (0.58 +/- 0.26 x 10(4)/min(1) /microU/ mL), three of the five subjects had a decline in insulin sensitivity.

CONCLUSIONS

Elevated blood glucose during the luteal phase may increase insulin-independent glucose disposal. Some individuals appear more responsive to menstrual cycle effects on insulin sensitivity. Women should be encouraged to use available self-monitoring technology to identify possible cyclical variations in blood glucose that might require clinician review and insulin dosage adjustments.

Insulin sensitivity and premenstrual syndrome

Maintaining normal blood glucose levels is a constant challenge for women with diabetes. Anecdotal reports reveal that many women question if menstrual cycle phases may affect their blood glucose levels. However, results from studies investigating the effect of the menstrual cycle on insulin sensitivity in diabetic women have been conflicting. One variable that may account for the conflicting results is the presence or absence of premenstrual syndrome (PMS), which may exacerbate menstrual cycle-related effects on insulin sensitivity. Treatment of PMS with serotonin reuptake inhibitors may alleviate the symptoms of PMS, as well as improve insulin sensitivity and help regulate blood glucose levels.

Effect of the ovarian hormones on GLUT4 expression and contraction-stimulated glucose uptake

This study examined the roles of the female sex steroids, 17beta-estradiol (E(2)) and progesterone (Prog), on glucose uptake and GLUT4 protein expression. Female Sprague-Dawley rats were either sham operated (C) or ovariectomized and treated with placebo (O), E(2) (E), Prog (P), or both hormones at physiological doses (P + E) or the same dose of Prog with a high dose of E(2) (P + HiE) via timed-release pellets inserted at the time of surgery, 15 days before metabolic testing. On the morning of day 15, animals received a 300-microCi injection (ip) of 2-deoxy-[(14)C]glucose and then either exercised on a motorized treadmill for 30 min at 0.35 m/s or remained sedentary in their cages for the same period. Basal glucose uptake was not different between the treatment groups in either the red or white quadriceps. However, glucose uptake was decreased (P < 0.05) in O, P, and P + E rats during exercise in the red quadriceps compared with C rats, whereas E and P + HiE treatment restored glucose uptake. Glycogen content in skeletal muscle followed similar trends, with no differences seen in resting animals. Postexercise red quadriceps glycogen levels were higher (P < 0.05) in the E and P + HiE rats compared with O and P. Treatment of ovariectomized rats with progesterone (P rats) decreased (P < 0.05) GLUT4 content in the red quadriceps by 21% compared with C rats. These data demonstrate that estrogen-deficient animals have a decreased ability for contraction-stimulated glucose uptake and increased glycogen use during aerobic exercise. However, changes in contraction-stimulated glucose uptake could not be explained by altered transporter protein content, since the absence of E(2) had no effect on GLUT4 protein.

The roles of estrogen and progesterone in regulating carbohydrate and fat utilization at rest and during exercise

OBJECTIVE

Compared with men, women use more fat and less carbohydrate to fuel exercise at the same relative intensity. Circulating levels of estrogen and progesterone are likely to play an important role in explaining this gender difference in exercise substrate utilization.

METHODS

Studies, mainly using animal models, have shown that estrogen increases fatty acid availability (lipolysis) and decreases carbohydrate availability and uptake. Studies conducted in humans corroborate the reduction in carbohydrate turnover and oxidation in the presence of estrogen, but the impact on fatty acid availability and utilization is less clear.

RESULTS

The effect of circulating estrogen may be mediated, at least in part, by changes in the sensitivity of stored carbohydrate and lipids to mobilization in response to epinephrine. The role of progesterone in metabolic regulation during exercise has not been systematically studied in humans.

CONCLUSIONS

Understanding the role of the ovarian hormones in fat and carbohydrate metabolism during exercise may have practical applications in terms of understanding the metabolic consequences of amenorrhea, menopause, and hormone replacement therapy (HRT).

Women at altitude: changes in carbohydrate metabolism at 4,300-m elevation and across the menstrual cycle

We hypothesized that, in women, the blood glucose response to a meal (BGR) would be lower after exposure to 4,300 m compared with sea level (SL) and that BGR would be reduced in the presence of estrogen plus progesterone (E+P) relative to estrogen alone (E). Sixteen women were studied in both the E and E+P conditions at SL and in either the E or E+P condition at 4,300 m. On day 9 in each condition, blood was sampled before, and every 30 min for 2 h after, the subjects ate a high-carbohydrate meal. At 4,300 m, BGR peaked at a lower value (5.73 +/- 0.94 mM) than at SL (6.44 +/- 1.45 mM) and returned to baseline more slowly (P < 0.05). Plasma insulin values were the same but C peptide was slightly higher at 4,300 m (P < 0. 05). At SL, BGR returned to baseline more slowly in E+P condition (5. 13 +/- 0.89 and 5.21 +/- 0.91 mM at 60 and 90 min, respectively) relative to E condition (4.51 +/- 0.52 and 4.69 +/- 0.88 mM, respectively) (P < 0.05). Insulin and C peptide were not different between E and E+P conditions. The data indicate that BGR is lower in women at high altitude compared with the SL, possibly due to greater suppression of hepatic glucose production or stimulation of peripheral glucose uptake by insulin. BGR was lower in E condition relative to E+P condition at SL and possibly at 4,300 m, but the relative concentrations of ovarian hormones do not appear to alter the magnitude of the change in BGR when women are exposed to high altitude.