Effect of Energy Deficiency on Estrogen Metabolism in Premenopausal Women

Moderate Weight Loss is associated with Reductions in LH Pulse Frequency and Increases in 24-hour Cortisol with no change in Perceived Stress in Young Ovulatory Women

OBJECTIVE

Determine the potential role of cortisol as an indicator of both metabolic and psychosocial stress and its relation to LH pulse dynamics during a three-month diet and exercise intervention causing moderate weight loss.

METHODS

Secondary analysis of a randomized, controlled trial that demonstrated the causal role of low energy availability in the disruption of the menstrual cycle. Twenty-one women aged (18-24 yrs), BMI (21.7± 1.9 kg·m^-2), completed a baseline menstrual cycle and three intervention menstrual cycles of a controlled diet and supervised exercise program. Twenty-four-hour LH pulse dynamics (q10 min) and diurnal patterns of cortisol (q60 min) as well as Perceived Stress Scale scores were determined in the early follicular phase prior to the intervention and in the post intervention cycle. Pre to post comparisons were determined with paired t-tests, and Pearson bivariate correlations assessed associations.

RESULTS

Subjects lost weight (-2.8±1.97 kg) and LH pulse frequency declined pre=0.79±0.23 pulses·hr^-1 to post=0.60±0.29 pulses·hr^-1 (p=0.014). Weight loss was associated with an increase in cortisol AUC R=-0.473, (p=0.03) and the decline in LH pulse frequency R= 0.523; (p=0.026). Increases in cortisol AUC were associated with declines in LH pulse frequency R=-0.472; (p=0.048). The morning cortisol rise AUC increased from pre=2140±878 µg·dL^-1 · day to post=2556±1067 µg·dL^-1 · day (p=0.034). Changes in PSS were not associated with changes in LH or cortisol.

CONCLUSION

The initial perturbation of LH pulsatility with moderate diet and exercise is associated with metabolically driven increases in cortisol AUC with no influence of psychological stress.

Energy Availability Is Associated With Luteinizing Hormone Pulse Frequency and Induction of Luteal Phase Defects

OBJECTIVE

Determine the interrelations between reductions in energy availability (EA), luteinizing hormone (LH) pulse frequency, and the induction of menstrual disturbances in previously sedentary, ovulatory women.

METHODS

Secondary analysis of a randomized controlled trial consisting of a 3-month controlled diet and supervised exercise program. EA was calculated daily by measured energy intake (kcal) and exercise energy expenditure (kcal) normalized to fat-free mass (kg) and averaged during baseline and each of 3 intervention menstrual cycles. Blood samples were obtained every 10 minutes for 24 hours in the early follicular phase before the intervention and after 3 months of diet and exercise (n = 14). LH pulse dynamics were assessed by Cluster. Linear mixed models determined whether EA predicts LH pulse frequency and LH pulse frequency predicts luteal phase defects (LPDs).

RESULTS

Subjects were 20 ± 1 years old, 165.1 ± 1.4 cm tall, and weighed 58.9 ± 1.5 kg. LH pulse frequency decreased from 0.82 ± 0.06 pulses/h to 0.63 ± 0.09 pulses/h (P = 0.048) as a result of the intervention which produced modest (-3.2 ± 0.6 kg) weight loss. EA, averaged across a menstrual cycle, predicted LH pulse frequency (P = 0.003) such that a single-unit decrease in EA was associated with a 0.017 pulses/h decrease in LH pulse frequency. LH pulse frequency in cycles with LPDs was 49% of that observed in cycles with no menstrual disturbances and for every 0.1-unit decrease in LH pulse frequency, the odds of having an LPD were 22× greater than having an optimal ovulatory cycle (P = 0.01).

CONCLUSIONS

Modest reductions in EA over a prolonged period are associated with decreased LH pulse frequency and the induction of menstrual disturbances.

Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold

INTRODUCTION

Chronic reductions in energy availability (EA) suppress reproductive function. A particular calculation of EA quantifies the dietary energy remaining after exercise for all physiological functions. Reductions in luteinizing hormone pulse frequency have been demonstrated when EA using this calculation is <30 kcal·kg·fat-free mass (ffm)·d.

PURPOSE

We determined whether menstrual disturbances (MD) are induced when EA is <30 kcal·kg ffm·d.

METHODS

Thirty-five sedentary, ovulatory women age 18 to 24 yr (weight, 59.0 ± 0.8 kg; body mass index, 21.8 ± 0.4 kg·m) completed a diet and exercise intervention over three menstrual cycles. Participants were randomized to groups that varied in the magnitude of negative energy balance created by the combination of exercise and energy restriction. Menstrual disturbances were determined using daily urinary estrone-1-glucuronide and pregnanediol glucuronide, midcycle luteinizing hormone, and menstrual calendars. In a secondary analysis, we calculated EA from energy balance data and tested the association of EA with MD.

RESULTS

A generalized linear mixed-effects model showed that the likelihood of a MD decreased by 9% for each unit increase in EA (odds ratio, 0.91; 95% confidence interval, 0.84-0.98; P = 0.010). No specific value of EA emerged as a threshold below which MD were induced. When participants were partitioned into EA tertile groups (low EA, 23.4-34.1; n = 11; moderate EA, 34.9-40.7; n = 12, and high EA, 41.2-50.1; n = 12 [kcal·kg ffm·d]), estrone-1-glucuronide (P < 0.001), pregnanediol glucuronide (P < 0.001), and luteal phase length (P = 0.031) decreased significantly, independent of tertile.

CONCLUSIONS

These findings do not support that a threshold of EA exists below which MD are induced but do suggest that MD increase linearly as EA decreases. Menstrual disturbances can likely be prevented by monitoring EA using a simplified assessment of metabolic status.

Physical Exercise Positively Influences Breast Cancer Evolution

Breast cancer is one of the most commonly diagnosed types of cancer in women. Its pathogenesis involves genetic, hormonal, and environmental factors. A large body of evidence indicates that physical activity has positive effects on every aspect of breast cancer evolution, including prevention, medical treatment, and aftercare clinical settings. Thus, different types of exercise can influence the prevention and progression of the disease through several common mechanisms, such as reduction of insulin resistance and improvement of immunity and cardiovascular function. Furthermore, acute and chronic symptoms of breast cancer, such as cachexia, muscle mass loss, fatigue, cardiotoxicity, weight gain, hormone alterations, bone loss, and psychologic adverse effects, may all be favorably influenced by regular exercise. We review the relation of intensity and duration of exercise with potential pathophysiologic pathways, including obesity-related hormones and sex steroid hormone production, oxidative stress, epigenetic alterations such as DNA hypomethylation, and changes in telomere length, within the context of the beneficial effects of exercise. The potential role of exercise in reducing the intensity of the adverse effects that result from breast cancer and anticancer treatment is also discussed.

Physical Exercise Prescription in Metabolic Chronic Disease

Metabolic syndrome as a consequence of the association to overweight, hypertension, and diabetes is at high risk of coronary events. Regular physical training has been recently promoted to reduce cardiovascular risks factors, by the improved lifestyle and also by the "anti-inflammatory effectiveness." A positive impact has been shown in case of cancer survived patients either with or without comorbidities and especially in those subjects where the inflammatory process is globally represented. The American College of Sports Medicine (ACSM) guidelines and more recently a new Italian model both support the role of "exercise as therapy" at moderate level of energy expenditure. The importance to establish the individual level of physical exercise, like a drug's dose, has induced authors in investigating this aspect in diverse diseases and in different clinical fields associated to an incorrect lifestyle habits. To reach this goal, a specific research strategy is important to spread the knowledge.

Magnitude of daily energy deficit predicts frequency but not severity of menstrual disturbances associated with exercise and caloric restriction

We assessed the impact of energy deficiency on menstrual function using controlled feeding and supervised exercise over four menstrual cycles (1 baseline and 3 intervention cycles) in untrained, eumenorrheic women aged 18-30 yr. Subjects were randomized to either an exercising control (EXCON) or one of three exercising energy deficit (ED) groups, i.e., mild (ED1; -8 ± 2%), moderate (ED2; -22 ± 3%), or severe (ED3; -42 ± 3%). Menstrual cycle length and changes in urinary concentrations of estrone-1-glucuronide, pregnanediol glucuronide, and midcycle luteinizing hormone were assessed. Thirty-four subjects completed the study. Weight loss occurred in ED1 (-3.8 ± 0.2 kg), ED2 (-2.8 ± 0.6 kg), and ED3 (-2.6 ± 1.1 kg) but was minimal in EXCON (-0.9 ± 0.7 kg). The overall sum of disturbances (luteal phase defects, anovulation, and oligomenorrhea) was greater in ED2 compared with EXCON and greater in ED3 compared with EXCON AND ED1. The average percent energy deficit was the main predictor of the frequency of menstrual disturbances (f = 10.1, β = -0.48, r(2) = 0.23, P = 0.003) even when weight loss was included in the model. The estimates of the magnitude of energy deficiency associated with menstrual disturbances ranged from -22 (ED2) to -42% (ED3), reflecting an energy deficit of -470 to -810 kcal/day, respectively. This is the first study to demonstrate a dose-response relationship between the magnitude of energy deficiency and the frequency of exercise-related menstrual disturbances; however, the severity of menstrual disturbances was not dependent on the magnitude of energy deficiency.

The effects of aerobic exercise on estrogen metabolism in healthy premenopausal women

BACKGROUND

It is well accepted that exercise can decrease breast cancer risk. Limited clinical evidence suggests that this risk could be mediated through changes in estrogen metabolism in premenopausal women. Our objective was to investigate the effects of exercise on premenopausal estrogen metabolism pertinent to breast cancer risk.

METHODS

Sedentary, healthy, young eumenorrheic women were randomized into an intervention of 30 minutes of moderate-to-vigorous aerobic exercise five times a week for approximately 16 weeks (n = 212), or into a usual-lifestyle sedentary control group (n = 179). Urinary levels of estrogens [estrone [E1], estradiol, and estriol] and nine estrogen metabolites were measured at baseline and at study end by liquid chromatography/tandem mass spectrometry. The ratios of 2-hydroxyestrone to 16α-hydroxyestrone (2-OHE1/16α-OHE1) and 2-OHE1 to 4-hydroxyestrone (2- OHE1/4-OHE1) were also calculated.

RESULTS

The exercise intervention resulted in significant increases in aerobic fitness and lean body mass and a significant decrease in percent body fat. For exercisers who completed the study (n = 165), 2-OHE1/16α-OHE1 increased significantly (P = 0.043), whereas E1 decreased significantly (P = 0.030) in control participants (n = 153). The change from baseline in 2-OHE1/16α-OHE1 was significantly different between groups (P = 0.045), even after adjustment for baseline values.

CONCLUSIONS

The exercise intervention resulted in a significant increase in the 2-OHE1/16α-OHE1 ratio but no differences in other estrogen metabolites or ratios.

IMPACT

Our results suggest that changes in premenopausal estrogen metabolism may be a mechanism by which increased physical activity lowers breast cancer risk.

[Relation between physical activity, weight balance and breast cancer]

Many epidemiologic studies, with a good methodology, support the evidence of the positive role of regular physical activity on primary and tertiary prevention of breast cancer on the risk of recurrence and mortality. This relation depends on the level of total energy expenditure by week, which helps balance weight on lifetime, an essential part of benefit. The beneficial effects of physical activity are linked to many interrelated additional mechanisms: in a short-term, contraction of skeletal muscles involves aerobic metabolism which utilizes glucose and amino acids like glutamine, improves insulin sensitivity and lowers plasma insulin; in a long-term, physical activity produces favorable changes in body composition, decreasing body fat and increasing lean mass. That is a key point to reduce the intake of energy substrates stimulating carcinogenesis, to improve insulin sensitivity, to change the ratio of leptin and adiponectin, to enhance cellular immunity and to block cellular pathways of cell proliferation and angiogenesis. Maintaining a healthy weight through regular physical activity well balanced with energy intake is it a goal for prevention of breast cancer.

Diabetes, overweight and risk of postmenopausal breast cancer: a case-control study in Uruguay

Obese postmenopausal women increase their risk of developing breast cancer (BC), in particular if they display an android-type pattern of adiposity, which is also associated to increased risks of diabetes mellitus, hypertension and cardiovascular disease. In order to explore the associations among anthropometry (body mass index, body composition, somatotype), some specific items of medical history (diabetes, hypertension, dislypidemias, hyperuricemia) and the risk of BC in Uruguayan women, a case-control study was carried out between 2004-2009 at our Oncology Unit. 912 women of ages between 23-69 years (367 new BC cases and 545 non hospitalized, age-matched controls with a normal mammography) were interviewed. Twenty body measurements were taken in order to calculate body composition and somatotype. Patients were queried on socio-demographics, reproductive history, family history of cancer, a brief food frequency questionnaire and on personal history of diabetes, dislypidemias, hyperuricemia, hypertension and gallbladder stones. Uni- and multivariate analyses were done, generating odds ratios (ORs) as an expression of relative risks. A personal history of diabetes was positively associated to BC risk (OR=1.64, 95% CI 1.00-2.69), being higher among postmenopausal women (OR=1.92, 95% CI 1.04-3.52). The risks of BC for diabetes in postmenopausal women with overweight combined with dislypidemia (OR=9.33, 95% CI 2.10-41.5) and high fat/muscle ratio (OR=7.81, 95% CI 2.01-30.3) were significantly high. As a conclusion, a personal history of diabetes and overweight was strongly associated to BC. The studied sample had a subset of high-risk of BC featured by postmenopausal overweight and diabetic women, who also had a personal history of hypertension and/or dyslipidemia. The present results could contribute to define new high risk groups and individuals for primary as well as for secondary prevention, since this pattern linked to the metabolic syndrome is usually not considered for BC prevention.

Increased 2-hydroxylation of estrogen is associated with lower body fat and increased lean body mass in postmenopausal women

Menopause is associated with changes in bone, muscle and fat mass. The importance of postmenopausal estrogen metabolism in bone health has been established. However, its relationship to body composition in postmenopausal women remains undetermined. The objective of this study is to determine the association between estrogen metabolism and body composition in postmenopausal women. This is a cross sectional study of 97 postmenopausal Caucasian women, 49-80 y.o., ≥1 year from the last normal menstrual period or those who have had oophorectomy. Inactive [2-hydroxyestrone (2OHE(1))] and active [16α-hydroxyestrone (16α-OHE(1))] urinary metabolites of estrogen were measured by ELISA. The whole and regional body composition was measured by DXA. We have found that both 2OHE(1), and 2OHE(1)/16α-OHE(1) ratio were negatively correlated with % total fat, and % truncal fat but positively correlated with % total lean mass. Comparing the fat and lean parameters of body composition according to tertiles of 2OHE(1) and 2OHE(1)/16αOHE(1) ratio showed that subjects in the lowest tertiles, had the highest % total fat, and % truncal fat and the lowest % total lean mass. Multiple regression analysis also showed 2OHE(1) and calcium intake as statistically significant predictors of all body composition parameters. In conclusion, in postmenopausal women, an increase in the metabolism of estrogen towards the inactive metabolites is associated with lower body fat and higher lean mass than those with predominance of the metabolism towards the active metabolites.

The manner in which calories are restricted impacts mammary tumor cancer prevention

Although treatments for breast cancer have improved and long-term survival after diagnosis is now common, prevention of the disease is the ultimate goal. Weight loss or weight maintenance is one approach that has been recommended to reduce the risk of breast cancer, particularly for peri/postmenopausal women. This approach is supported by decades of data indicating that calorie restriction prevents spontaneous and chemically induced mammary tumor development in rodents. In most cases, calorie restriction was implemented by a consistent daily reduction of calories, i.e. chronic calorie restriction (CCR). There have also been several studies where periods of reduced caloric intake were followed by periods of refeeding, i.e. intermittent calorie restriction (ICR), resulting in the prevention of spontaneous mammary tumorigenesis. In most of the early studies, there were no direct comparisons of CCR to ICR. One study using moderate calorie restriction in a chemically induced breast cancer rat model found a slight increase in mammary tumor incidence compared with ad libitum fed and CCR rats. However, recently, it has been demonstrated in several transgenic mouse models of breast cancer that ICR consistently provided a greater degree of protection than CCR. This review will provide a detailed comparison of ICR and CCR for breast cancer prevention. It will also examine potential mechanisms of action that may include periods of reduced IGF-I and leptin as well as an increase in the adiponectin:leptin ratio. Application of this approach to at-risk women may provide an approach to lower the risk of breast cancer in overweight/obese women.

Urinary 2/16 estrogen metabolite ratio levels in healthy women: a review of the literature

This is a summary of the published literature on the urinary 2/16 estrogen metabolite ratio in human populations, and a report the observed range of normal values in healthy women. Original research studies that included the measurement of urinary estrogen metabolites in human subjects were identified through an extensive Medline search; 43 distinct studies were identified, including a total of 6802 healthy women. The range of mean values of the 2/16 ratio measured with the ELISA method varied from 0.98 to 1.74; in studies of pre-menopausal women the range of mean values was 1.5-2.74, in studies of post-menopausal women mean values ranged from 1.15 to 2.25. The heterogeneity across studies was highly significant (p-value Q-test: <0.0001). In multivariable analyses, only race confirmed its role as an independent predictor of 2/16 ratio (F-value: 7.95; p-value: 0.009), after adjustment for age and menopausal status. There appears to be a large body of data on the 2/16 urinary ratio in healthy women. However, summary estimates are difficult to perform due to the high variability of the published study-specific values. The data suggests that race may be a contributor to 2/16 urinary ratio levels.

Effects of exercise combined with caloric restriction on inflammatory cytokines

Chronic inflammation has been implicated in the pathogenesis of several chronic diseases, such as atherosclerosis and diabetes, as well as certain types of cancers. It has been suggested that circulating biomarkers for inflammation may be modified by exercise; however, few laboratory-based studies have been conducted in nonobese premenopausal women. The purpose of this investigation was to determine the impact of a 4-month exercise training and caloric-restriction intervention with the goal of weight loss on circulating biomarkers of inflammation in sedentary premenopausal women aged 25–40 years (weight, 57 ± 2 kg). Subjects were studied for 6 consecutive menstrual cycles: 1 Screening, 1 Baseline, then 4 interventions (Interventions 1–4). Supervised aerobic training, consisting primarily of treadmill running and elliptical machine exercise, was performed 4 times per week for 40–90 min at 79% ± 0.7% of maximal heart rate. Subjects also consumed 30% fewer calories vs. baseline (1863 ± 58 to 1428 ± 53 kcal·day–1 (1 kcal = 4.186 kJ), p < 0.0001). Circulating inflammatory biomarkers, including adiponectin, high-sensitivity (hs) C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interferon-gamma (IFN-γ), and leptin, as well as body composition, aerobic capacity, and energy balance, were measured before and after the intervention. Maximal aerobic capacity increased by 8.5 ± 1.7 mL·kg–1·min–1 (p < 0.001) and body mass declined by an average of 3.7 ± 0.5 kg (p < 0.001). Significant reductions in IL-6 (0.39 ± 0.04 to 0.30 ± 0.03 pg·mL–1, p = 0.025), IFN-γ (0.58 ± 0.83 to 0.42 ± 0.64 pg·mL–1, p = 0.030), and leptin (13.18 ± 1.28 to 6.28 ± 0.71 pg·mL–1, p < 0.001) were detected in response to the intervention. No significant changes in adiponectin, hs-CRP, or TNF-α were found. Weight loss in response to exercise training and caloric restriction is effective in reducing inflammatory markers, specifically IL-6 and leptin.

Estrogen and progesterone exposure is reduced in response to energy deficiency in women aged 25-40 years

BACKGROUND

Alterations in circulating steroids are believed to be important mediators of the impact that diet and exercise have on breast cancer risk and changes in bone density. This study aimed to test the hypothesis that moderate exercise training combined with caloric restriction would produce significant menstrual disturbances and alterations in ovarian steroids in premenopausal women.

METHODS

Sedentary premenopausal women (25-40 years; body mass index: 23.6 +/- 0.6 kg/m(2)) assigned to either a light conditioning (LC, n = 9) or an exercise combined with caloric restriction group (EX + CR, n = 24) were studied for one screening, one baseline and four intervention periods equivalent to the length of subjects' menstrual cycles. Exercise consisted of supervised training sessions, i.e. two LC or four EX + CR times per week, 30-60 min at a moderate intensity. The EX + CR group was prescribed a diet representing a caloric restriction of 20-35% below baseline energy requirements, whereas the LC group remained eucaloric. Ovarian steroid exposure was determined with daily urinary estrone-1- and pregnanediol glucuronides (E1G and PdG, respectively) and mid-cycle urinary LH measures. Fitness, body composition, and serum sex hormone binding globulin (SHBG) and serum estradiol (E2) were assessed repeatedly.

RESULTS

The intervention produced significant increases in VO(2) max and decreases in both body weight (-3.7 +/- 0.5 kg; ranged from -8.8 to +1.8 kg) and percent body fat (-4.5 +/- 0.7%; ranged from -12 to +0.3%), which were attributable primarily to changes in the EX + CR subjects (time x group; P < 0.05). Serum E2 and urinary E1G and PdG concentrations declined significantly across the intervention period (time; P < 0.05), whereas SHBG increased transiently (time; P < 0.05) in the EX + CR subjects, with no significant changes observed in the LC group. The decrease in E1G area under the curve was significantly related to the daily energy deficit (R =0.61; P = 0.003), not the amount of weight lost. There was no significant impact of the intervention on menstrual cyclicity or the incidence of menstrual disturbances in either group.

CONCLUSIONS

A moderate aerobic exercise training program combined with modest weight loss in accordance with recommended guidelines produces significant reductions in ovarian steroid exposure without disrupting menstrual cyclicity in premenopausal women aged 25-40 years. Exposure to a daily energy deficit is a stronger predictor of the decline in estrogen exposure than decreases in body weight.

Hormonal and metabolic modulation through nutrition: towards a primary prevention of breast cancer

Breast cancer (BC) is a polygenic and multifactorial disease for which estrogens have been recognized as the main risk factor, and for which lifestyle plays a key role. Previous epidemiologic cancer research performed in Uruguayan population delimited its dietary and anthropometric profiles. Recognizing the difficulty for universalizing a nutritional basis for prevention due to different eating patterns among regions and countries, we summarize the existent knowledge linking nutrition, estrogens, metabolism and BC. As an attempt towards primary prevention of BC, we present recommendations mainly based on country-specific research findings and modifiable putative risk and protective factors, proposing to modify the intake of meats and other fatty foods--especially sources of Ω-6 and Ω-3 fatty acids--adding olive oil, selected vegetables, citrus fruits and working towards adequate body fat/muscle proportions. From a medical and ethical viewpoint, it is justified to recommend certain nutritional changes to women, because no adverse side effects are expected to occur.