-
1.
The influence of vitamin D supplementation and strength training on health biomarkers and chromosomal damage in community-dwelling older adults.
Draxler, A, Franzke, B, Kelecevic, S, Maier, A, Pantic, J, Srienc, S, Cellnigg, K, Solomon, SM, Zötsch, C, Aschauer, R, et al
Redox biology. 2023;61:102640
-
-
-
Free full text
Plain language summary
Aging is associated with a decline in physiological and physical function resulting in reduced physical activity, all of which are driving factors to the onset of chronic diseases and physical impairment. Older adults are often deficient in micronutrients, specifically vitamin D, which has been shown to have detrimental effects on the immune system, inflammatory and healing processes of fractured bones and also cardiovascular health beyond other musculoskeletal effects. The aim of this study was to investigate the effect of different vitamin D regimens in older individuals during an ongoing strength training period of 10 weeks while receiving vitamin D supplementation at the recommended level of 800 IU per day vs. a single dose of 50.000 IU per month. The data presented in this paper are part of the NutriAging Vitamin D study. The study was a randomised placebo-controlled double-blind trial which recruited one hundred community-dwelling women and men (aged 65–85 years). Participants were randomly allocated into three intervention groups, either the control group, the vitamin D daily (VDD) or the vitamin D monthly group (VDM). Results showed that oxidative stress might have played a role in the detrimental progress on chromosomal stability parameters since the protective effect of GSH (reduced glutathione) was reduced in all study groups at the end of the intervention, but the least reduction occurred in the VDD group. Authors concluded that a supplementation with the recommended dose of 800 IU vitamin D per day might be more advantageous when it comes to chromosomal stability parameters in older, formerly untrained participants undergoing demanding resistance exercise for 10 weeks.
Abstract
Older adults lack of proper physical activity which is often accompanied by vitamin D deficiency. Those factors are known to contribute to health issues in the later years of life. The main goal of this intervention study was to investigate the effect of different vitamin D supplementation strategies for 4 weeks solely or combined with a 10-week strength training program on chromosomal stability in peripheral blood mononuclear cells in community-dwelling older people. One hundred women and men (65-85 years) received either vitamin D3 daily (800 IU), a monthly dose (50.000 IU) or placebo for 17 weeks. All groups received 400 mg calcium daily. The fitness status of the study participants was measured using the 30- second chair stand test, the handgrip strength test and the 6-min walk test. The cytokinesis block micronucleus cytome (CBMN) assay was applied to analyze chromosomal anomalies, including cytotoxic and genotoxic parameters. Changes in antioxidant markers were measured in plasma. Walking distance and chair stand performance improved significantly. Increased levels of the parameters of the CBMN assay were detected for all intervention groups at study end. At baseline micronuclei (MNi) frequency correlated significantly with BMI in both sexes (females: r = 0.369, p = 0.034; males: r = 0.265, p = 0.035), but not with vitamin D serum levels. In females, body fat (r = 0.372, p < 0.001) and functional parameter using the 30-s chair stand test (r = 0.311, p = 0.002) correlated significantly with MNi frequency. Interestingly, not vitamin D supplementation but 10 weeks of resistance training increased MNi frequency indicating elevated chromosomal instability and also adverse effects on antioxidant markers including glutathione and FRAP were detected in the group of community-dwelling older adults.
-
2.
Impact of a ketogenic diet intervention during radiotherapy on body composition: V. Final results of the KETOCOMP study for head and neck cancer patients.
Klement, RJ, Sweeney, RA
Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al]. 2022;198(11):981-993
-
-
-
Free full text
-
Plain language summary
Head and neck cancer (HNC) describes cancers originating from the lip, oral and nasal cavity, paranasal sinuses, pharynx, larynx, and trachea. Patients with HNC frequently present with feeding difficulties and malnutrition, which are often further aggravated by tobacco and alcohol abuse and a general unhealthy lifestyle. This study aimed to investigate the impact of a ketogenic diet (KD) versus an unspecified standard diet (SD) on body composition and survival in HNC patients undergoing radio(chemo)therapy. This study is a controlled clinical trial. Results show that an individualized KD supplemented with essential amino acids consumed during curative radio(chemo)therapy of HNC patients was able to slow down the negative consequences of therapy on body composition to some extent. Authors conclude that further research of KDs in frail cancer patient populations is required which may help to motivate their implementation as complementary therapies for select patients.
Abstract
PURPOSE Patients with head and neck cancer (HNC) are at risk of malnutrition, especially during radiochemotherapy. We aimed to study the impact of a ketogenic diet (KD) versus an unspecified standard diet (SD) on body composition and survival in HNC patients undergoing radio(chemo)therapy. METHODS As part of a controlled clinical trial, non-metastasized HNC patients were enrolled into either a KD (N = 11) or an SD (N = 21) group between May 2015 and May 2021. Body composition was measured weekly by bioimpedance analysis and analyzed using linear mixed effects models. Overall and progression-free survival was assessed during regular follow-up. RESULTS A total of 7 KD and 21 SD patients completed the study and were eligible for comparative analysis. Chemotherapy was significantly associated with declines in all body composition parameters, while the KD had opposing, yet nonsignificant effects. In patients receiving chemotherapy, average weekly reductions of body mass (BM) and skeletal muscle mass (SMM) were 0.9 kg and 0.31 kg in the KD group versus 1.2 kg and 0.57 kg in the SD group, respectively. Patients in the KD group receiving no chemotherapy achieved an average increase of 0.04 kg BM and 0.12 kg SMM per week. After a median follow-up of 42 months (range 6.7-78 months) there were no significant differences in progression-free or overall survival between the groups. CONCLUSION The KD may partially counteract the detrimental effects of radiochemotherapy on body composition in HNC patients. This should encourage further research into KDs in frail cancer patient populations and motivate their implementation as complementary therapy for selected patients.
-
3.
Relationship between energy availability, energy conservation and cognitive restraint with performance measures in male endurance athletes.
Jurov, I, Keay, N, Hadžić, V, Spudić, D, Rauter, S
Journal of the International Society of Sports Nutrition. 2021;18(1):24
-
-
-
Free full text
Plain language summary
Athletes who do endurance exercise sometimes experience low energy availability which can affect their performance. Low energy availability may lead to a syndrome called Relative energy deficiency in sports. This cross-sectional controlled study assessed the pre-race energy availability in twelve lean, healthy endurance athletes without pre-existing signs of relative energy deficiency. Results showed that two-thirds of the participants had low mean energy availability. Lower energy availability was associated with higher energy expenditure. Participants in the study deliberately restricted their energy intake to achieve an optimal body composition. This may have led to energy conservation in participants. However, the study failed to show any associations between energy conservation and energy availability. There is a need for more robust studies to determine the true cut-off value of energy availability in male endurance athletes. Healthcare professionals can use the results of this study to understand the need for eating behaviour screening to reduce disordered eating in endurance athletes and the clinical applicability of energy conservation assessment.
Abstract
BACKGROUND Low energy availability in male athletes has gained a lot of attention in recent years, but direct evidence of its effects on health and performance is lacking. The aim of this research was to objectively measure energy availability (EA) in healthy male endurance athletes without pre-existing relative energy deficiency signs during pre-race season. METHODS Twelve trained endurance athletes (performance level 3, 4, and 5) participated in the cross-sectional controlled laboratory study. Fat-free mass, exercise energy expenditure, and energy intake were measured to calculate EA. Resting energy expenditure was measured and estimated to assess energy conservation. Three specific performance tests were used to assess endurance, agility, and explosive strength performance. For psychological evaluation, the Three Factor Eating Questionnaire and a short Well-being questionnaire were completed. RESULTS Mean EA was 29.5 kcal/kg FFM/day. The majority (66.6%) had EA under the threshold for low EA in females. Critical cognitive restraint (≥13) was reported by 75% of participants. There were no differences in performance, blood values, or psychological evaluation when subjects were divided into two groups divided by EA = 30 kcal/kg FFM/day. Cognitive restraint was negatively associated with measured resting energy expenditure and energy conservation (r = -.578, p = .025 and r = -.549, p = .032, respectively). CONCLUSIONS The mean EA measured in this study supports the theory that the threshold for low EA in endurance male athletes might be under the threshold for females. In addition, we confirmed cognitive restraint could be useful for early detection of energy conservation. The high cognitive restraint as measured in our sample stressed the need of eating behavior screening in endurance athletes in order to reduce risk of any disordered eating patterns.
-
4.
Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes.
Sutton, EF, Beyl, R, Early, KS, Cefalu, WT, Ravussin, E, Peterson, CM
Cell metabolism. 2018;27(6):1212-1221.e3
-
-
-
Free full text
Plain language summary
Studies have shown that intermittent fasting (IF) can reduce body weight or body fat, as well as a number of metabolic markers. However, it is unknown whether the metabolic benefits are solely due to the weight loss. In addition, data from circadian studies suggest that eating earlier in the day has a positive effect on metabolism. The aim of this randomised, cross-over, controlled feeding trial was to evaluate the effects of early time-restricted feeding (eTRF) on weight and metabolic markers. eTRF was implemented as consuming all calories within a 6 hours window with the last meal no later than 3pm. 8 overweight men with prediabetes were randomized to either eTRF or a control schedule (12-hr feeding period) for 5 weeks, and later crossed over to the other schedule. During both eating regimes the same meals and calories were consumed in both groups in a controlled environment. eTRF improved insulin metabolism, blood pressure and oxidative stress, but not glucose levels, cholesterol or inflammatory markers. No weight loss occurred either during eTRF or control period, suggesting that the observed changes are independent of weight loss. The authors conclude that eTRF improves some aspects of cardiometabolic health and that these effects are not solely due to weight loss.
Abstract
Intermittent fasting (IF) improves cardiometabolic health; however, it is unknown whether these effects are due solely to weight loss. We conducted the first supervised controlled feeding trial to test whether IF has benefits independent of weight loss by feeding participants enough food to maintain their weight. Our proof-of-concept study also constitutes the first trial of early time-restricted feeding (eTRF), a form of IF that involves eating early in the day to be in alignment with circadian rhythms in metabolism. Men with prediabetes were randomized to eTRF (6-hr feeding period, with dinner before 3 p.m.) or a control schedule (12-hr feeding period) for 5 weeks and later crossed over to the other schedule. eTRF improved insulin sensitivity, β cell responsiveness, blood pressure, oxidative stress, and appetite. We demonstrate for the first time in humans that eTRF improves some aspects of cardiometabolic health and that IF's effects are not solely due to weight loss.
-
5.
Cardiovascular Biomarkers in Association with Dietary Intake in a Longitudinal Study of Youth with Type 1 Diabetes.
Sanjeevi, N, Lipsky, LM, Nansel, TR
Nutrients. 2018;10(10)
-
-
-
Free full text
Plain language summary
Cardiovascular disease (CVD) is the major cause of mortality and morbidity in patients with type 1 diabetes, whose risk is several-fold higher than the general population. The objective of this study was to investigate relationships of CVD biomarkers with overall diet quality, and its dietary components in youth with type 1 diabetes. This study is a secondary analysis of a randomised controlled trial of a family-based behavioural nutrition intervention. The control group had an equal frequency of contact with the research staff but did not receive any nutrition advice besides that included as part of regular type 1 diabetes care. Results indicate that greater intake of whole grains and whole fruits, and lower added sugar and polyunsaturated fatty acids were associated with more favourable CVD biomarkers. Authors conclude that overall diet quality was not associated with CVD biomarkers in youth with type 1 diabetes. However, specific dietary components were associated with CVD biomarkers, independent of glycaemic control.
Abstract
Despite cardioprotective effects of a healthy diet in the general population, few studies have investigated this relationship in individuals with type 1 diabetes, who are at elevated risks of cardiovascular disease (CVD) due to hyperglycemia. The objective of this study was to examine the association of CVD biomarkers with overall diet quality, as measured by the Healthy Eating Index-2015 (HEI-2015), and its dietary components in youth with type 1 diabetes. Youth with type 1 diabetes (n = 136, 8⁻16.9 years) were enrolled in an 18-month behavioral nutrition intervention trial. Dietary intake from three-day diet records, CVD biomarkers (total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C); triglycerides (TG), C-reactive protein (CRP), 8-iso-prostaglandin-F2alpha (8-iso-PGF2α), systolic and diastolic blood pressure (SBP and DBP, respectively), and glycated hemoglobin (HbA1c) were assessed at baseline, 6, 12 and 18 months. Linear mixed-effects models estimated associations of dietary intake with CVD biomarkers, adjusting for HbA1c and other covariates. Separate models estimated associations of time-varying change in dietary intake with time-varying change in CVD biomarkers. HEI-2015 was not associated with CVD biomarkers, but whole grain intake was inversely associated with TC, HDL-C and DBP, and a greater increase in whole fruit intake was associated with lower DBP. Added sugar, saturated fat and polyunsaturated fat were positively related to serum TG, HDL-C, and DBP, respectively. Findings suggest that the intake of specific dietary components, including whole grains, whole fruits, added sugar and PUFA, may influence cardiometabolic health in youth with type 1 diabetes, independent of glycemic control.
-
6.
Effect of A Very Low-Calorie Ketogenic Diet on Food and Alcohol Cravings, Physical and Sexual Activity, Sleep Disturbances, and Quality of Life in Obese Patients.
Castro, AI, Gomez-Arbelaez, D, Crujeiras, AB, Granero, R, Aguera, Z, Jimenez-Murcia, S, Sajoux, I, Lopez-Jaramillo, P, Fernandez-Aranda, F, Casanueva, FF
Nutrients. 2018;10(10)
-
-
-
Free full text
Plain language summary
Obesity is a multi-factorial disorder involving genetic, environmental, metabolic and behavioural factors. Few studies have examined the effect of weight-loss therapy on various psychobiological parameters associated with obesity. Therefore the aim of this 4-month nutritional intervention was to evaluate food and alcohol cravings, physical activity levels, sleep quality, sexual function and quality of life in patients with obesity after following a very low-calorie ketogenic (VLCK) diet. Twenty obese patients were enrolled and participated in psychological questionnaires and anthropometric measurements at four points throughout the intervention: at baseline, maximum ketosis, reduced ketosis and endpoint. A specialist physician and expert dietician closely monitored participants to ensure safety and duration of the ketosis state. This study found that rapid and sustained weight loss induced by a VLCK-diet is associated with better food control and improvements in quality of life in obese subjects. Based on these results, the authors conclude a VLCK-diet is a suitable and valuable treatment option for obese patients.
Abstract
Psychological well-being and hunger and food control are two relevant factors involved in the success of weight-loss therapy in treating obesity. Thus, this study aims to evaluate food and alcohol cravings, physical and sexual activity, sleep, and life quality (QoL) in obese patients following a very low-calorie ketogenic (VLCK) diet, as well as the role of weight lost and ketosis on these parameters. A battery of psychological test was performed in twenty obese patients (12 females, 47.2 ± 10.2 year and BMI of 35.5 ± 4.4) through the course of a 4-month VLCK diet on four subsequent visits: baseline, maximum ketosis, reduced ketosis, and endpoint. Each subject acted as their own control. Relevantly, the dietary-induced changes in body composition (7.7 units of BMI lost, 18 kg of fat mass (1.2 kg of visceral fat mass)) were associated with a statistically significant improvement in food craving scores, physical activity, sleepiness, and female sexual function. Overall, these results also translated in a notable enhancement in QoL of the treated obese patients. Therefore, the rapid and sustained weight and fat mass (FM) loss induced by the VLCK diet is associated with good food control and improvements in the psychological well-being parameters in obese subjects, which could contribute to the long-term success of this therapy.
-
7.
Food-specific IgGs Are Highly Increased in the Sera of Patients with Inflammatory Bowel Disease and Are Clinically Relevant to the Pathogenesis.
Xiao, N, Liu, F, Zhou, G, Sun, M, Ai, F, Liu, Z
Internal medicine (Tokyo, Japan). 2018;57(19):2787-2798
-
-
-
Free full text
Plain language summary
Inflammatory bowel disease (IBD) is an umbrella term incorporating ulcerative colitis (UC) and Crohn’s disease (CD). The exact reasons for the development of IBD are still being debated, however food allergy has been implicated. Diagnosis of food allergy is normally performed looking at the body’s immediate immune response, however the delayed immune response may be of importance in IBD. This study of 301 patients with IBD and 178 healthy controls aimed to look at the delayed immune response of individuals with IBD following the introduction of certain foods. It also looked at the efficacy of a drug treatment, infliximab (IFX) on this immune response. The results showed that the delayed immune response to egg, milk, wheat, corn, rice, tomato, codfish, and soya was increased in those with CD compared to those with UC and healthy control. Infliximab treatment was effective in suppressing this immune response in individuals with CD. It was concluded that in individuals with IBD, measuring the delayed immune response to foods may be an important diagnosis and management tool. This study could be used by healthcare professionals to understand that measuring the immediate immune response to certain foods in individuals with IBD, may not be sufficient. Measuring the delayed immune response in combination with the immediate immune response may give a better picture of foods which should be avoided in those with IBD. Infliximab treatment may be an effective treatment in patients with IBD and a delayed immune response to certain foods.
Abstract
Objective Dietary antigens are common luminal antigens in the gastrointestinal tract and have been considered to contribute to the pathogenesis of inflammatory bowel disease (IBD). We analyzed the levels of food-specific IgGs against a variety of dietary antigens, explored the clinical relevance of food allergy to the pathogenesis of IBD, and investigated whether or not infliximab (IFX) treatment could regulate the immune responses induced by dietary antigens. Methods A total of 301 IBD patients, including 201 patients with Crohn's disease (CD) and 100 patients with ulcerative colitis (UC), were recruited, and their serum food-specific IgGs against 14 food antigens were detected by a semi-quantitative enzyme linked immunosorbent assay (ELISA). Total serum IgG and IgE levels were measured by immunonephelometry and fluorescent enzyme immunoassay, respectively. Simultaneously, the relevant medical records and clinical data were collected for further analyses. Results Food-specific IgGs against egg, milk, wheat, corn, rice, tomato, codfish, and soybean antigens were found to be significantly increased in the sera of CD patients compared with UC patients and healthy controls (p<0.01). The levels of total serum IgG and IgE were also significantly higher in CD patients than in healthy controls (p<0.01). The titers of corn- and tomato-specific IgGs were found to be significantly correlated with total serum IgG in CD patients (p<0.05), while the titers of egg-, milk-, and wheat-specific IgGs were correlated with total serum IgE (p<0.05). Interestingly, IFX therapy was able to down-regulate the food-specific IgG-mediated immune response markedly in active CD patients. Conclusion Food-specific IgGs against egg, milk, wheat, corn, rice, tomato, codfish, and soybean are highly increased in the sera of CD patients. IFX treatment was able to down-regulate the levels of food-specific IgGs by suppressing intestinal inflammation and promoting mucosal healing. Therefore, food-specific IgGs may serve as an important approach in the diagnosis and management of food allergy in IBD.
-
8.
Effects of Three Commercially Available Sports Drinks on Substrate Metabolism and Subsequent Endurance Performance in a Postprandial State.
Qin, L, Wang, QR, Fang, ZL, Wang, T, Yu, AQ, Zhou, YJ, Zheng, Y, Yi, MQ
Nutrients. 2017;9(4)
-
-
-
Free full text
Plain language summary
The depletion of stored glucose and the reduction of the availability of carbohydrates can contribute to fatigue during moderate-to-high intensity exercise. Studies have shown that carbohydrate consumption can reduce the depletion of stored energy and that the combination of protein and carbohydrate supplementation resulted in greater replenishment during intense exercise. Nowadays, most commercial sports beverages contain both carbohydrates and proteins. The present study looked at the postprandial effects of commercially available beverages on carbohydrate and fat metabolism and exercise performance. Ten healthy male participants with a history of running or cycling exercise participated in two studies in a double-blinded, counterbalanced manner. Commercially available beverages with low carbohydrate, high carbohydrate, and a combination of proteins and carbohydrates were tested, and it was found that a beverage containing both proteins and carbohydrates maintained insulin levels and provided greater energy during endurance exercise. It is important to conduct future studies on athletes with higher fitness levels to evaluate the benefits of commercially available beverages. Based on the findings of this study, healthcare professionals can learn more about the benefits of commercially available beverages that combine carbohydrates and proteins and have a low carbohydrate content.
Abstract
Purpose: To examine the effects of commercially available sports beverages with various components on substrate metabolism and subsequent performance. Methods: Two studies were conducted in a double-blinded, counterbalanced manner. Study I was designed to determine the glycemic index, while study II determined the utilization of substrates and subsequent exercise performance. Ten healthy male participants (age 21.70 ± 2.41 years, height 176.60 ± 5.23 cm, weight 66.58 ± 5.38 kg, V̇O2max 48.1 ± 8.4 mL/kg/min) participated in both study I and study II. Three types of commercially available sports beverage powders were used. The powders consisted primarily of oligosaccharides (low molecular weight carbohydrates, L-CHO), hydrolyzed starch (high molecular weight CHO, H-CHO), and whey protein powder with carbohydrate (CHO-PRO). They were dissolved in purified water with identical CHO concentration of 8% (w/v). In study I, each participant underwent two oral glucose tolerance tests (OGTT) and one glycemic response test for each sports drink. In study II, participants cycled for 60 min at 70% V̇O2max, one hour after consuming a standardized breakfast. One of four prescribed beverages (L-CHO, H-CHO, CHO-PRO, and Placebo control, PLA) was served at 0, 15, 30, 45 min during the exercise. Six hours after the first exercise session, participants came back for a "time to exhaustion test" (TTE). Blood samples were drawn at 0, 30, and 60 min in the first exercise session, while arterial blood gas analysis was conducted at 0, 30, and 60 min in both sessions. Subjective feelings (rating of perceived exertion and abdominal discomfort) were also evaluated every 30 min during exercise. Results: Compared to the reference standardized glucose solution, the glycemic index of the L-CHO beverage was 117.70 ± 14.25, while H-CHO was 105.50 ± 12.82, and CHO-PRO was 67.23 ± 5.88. During the exercise test, the insulin level at 30 and 60 min was significantly lower than baseline following the treatment of L-CHO, H-CHO, and PLA (p < 0.05). The CHO oxidation rate at 60 min in the first exercise session was significantly higher than that at 60 min in the second exercise session following the L-CHO treatment (p < 0.05). Time to exhaustion was not significantly different (p > 0.05). Conclusion: The CHO sports beverage with additional PRO maintains insulin production during endurance cycling at 70% V̇O2max in the postprandial state. L-CHO sports beverage suppresses fat utilization during the subsequent exercise performance test. The subsequent exercise performance (as evaluated by TTE) was not influenced by the type of CHO or the addition of PRO in the commercially available sports beverages used in the present study.
-
9.
Beneficial Effects of a Dietary Weight Loss Intervention on Human Gut Microbiome Diversity and Metabolism Are Not Sustained during Weight Maintenance.
Heinsen, FA, Fangmann, D, Müller, N, Schulte, DM, Rühlemann, MC, Türk, K, Settgast, U, Lieb, W, Baines, JF, Schreiber, S, et al
Obesity facts. 2016;9(6):379-391
-
-
-
Free full text
Plain language summary
Recent findings have suggested that the composition of the gut microbiome plays an important role in energy balance and metabolism. The aim of this study was to examine if weight loss altered the gut micriobiota diversity and to determine whether these changes were sustained during a weight maintenance period. Dietary intervention included a very low calorie diet (800 kcal/day) for three months followed by a weight maintenance period for three months. This study consisted of three groups – an intervention of 18 obese adults, a control of 13 lean adults and a second control of 13 obese adults. This study found that a very low calorie diet intervention in obese humans over a three-month period resulted in a significant change in microbiome diversity and metabolism, however these changes diminished during the weight maintenance period. Based on these findings, the authors suggest that nutritional components may exert a stronger effect on the human gut microbiome than changes in body weight or metabolism.
Abstract
OBJECTIVE In the present study, we examined the effect of a very low-calorie diet(VLCD)-based obesity program on human gut microbiome diversity and metabolism during weight loss and weight maintenance. METHODS Obese subjects underwent 3 months of VLCD followed by 3 months of weight maintenance. A lean and an obese control group were included. The microbiome was characterized by performing high-throughput dual-indexed 16S rDNA amplicon sequencing. RESULTS At baseline, a significant difference in the Firmicutes/Bacteroidetes ratio between the lean and obese individuals was observed (p = 0.047). The VLCD resulted in significant alterations in gut microbiome diversity from baseline to 3 months (p = 0.0053). Acinetobacter represented an indicator species for the observed effect (indicator value = 0.998, p = 0.006). Metabolic analyses revealed alterations of the bacterial riboflavin pathway from baseline to 3 months (pnom = 0.0078). These changes in diversity and bacterial metabolism induced by VLCD diminished during the weight maintenance phase, despite sustained reductions in body weight and sustained improvements of insulin sensitivity. CONCLUSION The present data show that a VLCD is able to beneficially alter both gut microbiome diversity and metabolism in obese humans, but that these changes are not sustained during weight maintenance. This finding might suggest that the microbiome should be targeted during obesity programs.
-
10.
Estrogen and progesterone exposure is reduced in response to energy deficiency in women aged 25-40 years.
Williams, NI, Reed, JL, Leidy, HJ, Legro, RS, De Souza, MJ
Human reproduction (Oxford, England). 2010;25(9):2328-39
-
-
-
Free full text
-
Plain language summary
Diet and exercise are related to a reduction in breast cancer risk, and it is thought that this is at least partly due to their impact on levels of female sex hormones. This study aimed to test the effect that exercise and calorie restriction have on menstruation and sex hormones in premenopausal women. Inactive women aged 25-40 years were recruited for the study, and allocated to two groups. One group was assigned a low-calorie diet that provided 20-35% lower calories than baseline energy needs, plus 4 sessions of moderate-intensity exercise per week. The control group followed a diet designed to ensure weight maintenance, and took part in shorter exercise sessions twice a week. Women in the low-calorie group experienced a 15% reduction in levels of oestradiol and a 20% reduction in the levels of oestrogen metabolite oestrone glucuronide. Larger reductions in oestrone glucuronide were related to higher energy deficits, suggesting that hormone production is sensitive to day-to-day fluctuations in energy balance. There was no change in the menstrual cycles of the participants. The researchers concluded that an energy deficit is a more important factor in reducing oestrogen exposure than losing weight.
Abstract
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.