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Effects of Two Years of Calorie Restriction on Aerobic Capacity and Muscle Strength.
Racette, SB, Rochon, J, Uhrich, ML, Villareal, DT, DAS, SK, Fontana, L, Bhapkar, M, Martin, CK, Redman, LM, Fuss, PJ, et al
Medicine and science in sports and exercise. 2017;49(11):2240-2249
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Caloric restriction (CR) has been shown to increase lifespan and delay age-related disease in many species. As a part of the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study, this particular study aimed to determine whether long-term CR adversely affects aerobic capacity and muscle strength in 218 healthy, nonobese adults. Participants were randomised to 25% CR or control group, and a VO2max treadmill test, knee flexor and extensor strength were all measured at baseline, one year and two years. This study showed that two years of CR without a structured exercise component did not appear to compromise aerobic capacity in healthy nonobese adults.
Abstract
PURPOSE Calorie restriction (CR) improves health span and delays age-related diseases in many species. The multicenter Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study was the first randomized controlled trial of CR in nonobese humans. The aim of this investigation was to determine the effects of CR on V˙O2max and muscle strength in the CALERIE trial. METHODS Healthy, normal-weight, and mildly overweight women and men (n = 218, mean ± SE age = 37.9 ± 0.5 yr) were randomized to 25% CR or an ad libitum (AL) control condition in a 2:1 allocation (143 CR, 75 AL). V˙O2max was determined with an incremental treadmill test; the strength of the knee flexors and extensors was assessed by dynamometry at baseline, 1 yr, and 2 yr. RESULTS The CR group achieved an average 11.9% ± 0.7% CR during the 2-yr intervention. Body weight decreased in CR (-7.7 ± 0.4 kg), but not AL (+0.2 ± 0.5 kg). Absolute V˙O2max (L·min) decreased at 1 and 2 yr with CR, whereas V˙O2max expressed relative to body mass increased at both time points (1 yr: +2.2 ± 0.4; 2 yr: +1.9 ± 0.5 mL·kg·min) and relative to AL. The CR group increased their treadmill test time and workload at 1 and 2 yr. Strength results in CR were similar, with decreases in absolute flexor and extensor strength, but increases when expressed relative to body mass. No changes were observed for V˙O2max expressed relative to lean body mass or leg lean mass. CONCLUSIONS Two years of modest CR without a structured exercise component did not appear to compromise aerobic capacity in healthy nonobese adults. The clinical implications of the observed changes in V˙O2max and muscle strength will be important to explore in future studies.
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Self-reported dietary fructose intolerance in irritable bowel syndrome: Proposed diagnostic criteria.
Berg, LK, Fagerli, E, Myhre, AO, Florholmen, J, Goll, R
World journal of gastroenterology. 2015;21(18):5677-84
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The mechanisms for fructose malabsorption (FM) are not clearly understood and the diagnostic techniques are suboptimal. There is increasing interest to use self-reported responses to a fructose-reduced diet (FRD) as a diagnostic tool, however there is no standardised procedure for performing FRD tests. The aim of this study was to define the criteria for self-reported dietary fructose intolerance and to evaluate subjective global assessment as an outcome measure in 182 IBS patients. Participants were randomised to either consume a fructose-reduced diet or maintain a normal IBS diet, and record their symptoms and stool movements daily. After 12 weeks, a fructose-rich provocation test was performed. This study found that a fructose-reduced diet improves symptoms in a subgroup of IBS patients, and proposes a new diagnostic standard for self-reported fructose intolerance.
Abstract
AIM: To study the criteria for self-reported dietary fructose intolerance (DFI) and to evaluate subjective global assessment (SGA) as outcome measure. METHODS Irritable bowel syndrome (IBS) patients were randomized in an open study design with a 2 wk run-in on a habitual IBS diet, followed by 12 wk with/without additional fructose-reduced diet (FRD). Daily registrations of stool frequency and consistency, and symptoms on a visual analog scale (VAS) were performed during the first 4 wk. SGA was used for weekly registrations during the whole study period. Provocation with high-fructose diet was done at the end of the registration period. Fructose breath tests (FBTs) were performed. A total of 182 subjects performed the study according to the protocol (88 FRD, 94 controls). RESULTS We propose a new clinically feasible diagnostic standard for self-reported fructose intolerance. The instrument is based on VAS registrations of symptom relief on FRD combined with symptom aggravation upon provocation with fructose-rich diet. Using these criteria 43 of 77 patients (56%) in the present cohort of IBS patients had self-reported DFI. To improve the concept for clinical evaluation, we translated the SGA scale instrument to Norwegian and validated it in the context of the IBS diet regimen. The validation procedures showed a sensitivity, specificity and κ value for SGA detecting the self-reported DFI group by FRD response within the IBS patients of 0.79, 0.75 and 0.53, respectively. Addition of the provocation test yielded values of 0.84, 0.76 and 0.61, respectively. The corresponding validation results for FBT were 0.57, 0.34 and -0.13, respectively. CONCLUSION FRD improves symptoms in a subgroup of IBS patients. A diet trial followed by a provocation test evaluated by SGA can identify most responders to FRD.
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Improving lactose digestion and symptoms of lactose intolerance with a novel galacto-oligosaccharide (RP-G28): a randomized, double-blind clinical trial.
Savaiano, DA, Ritter, AJ, Klaenhammer, TR, James, GM, Longcore, AT, Chandler, JR, Walker, WA, Foyt, HL
Nutrition journal. 2013;12:160
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Lactose intolerant (LI) individuals are recommended to limit consumption of dairy foods to reduce uncomfortable gut symptoms, however this may contribute to low calcium intake and the risk for chronic disease. Prior research has suggested that the bacteria in the gut can adapt, potentially allowing diary consumption without the negative symptoms in LI patients. The aim of this study is to investigate the efficacy, safety and tolerability of the galacto-oligosaccharide (GOS) RP-G28 in improving lactose digestion and the subsequent symptoms in LI patients. 85 adults aged 18 to 64 participated in the study and were randomly assigned to receive either RP-G28 or placebo for 35 days. After the treatment period, participants were followed for 30 days and lactose digestion was measured using the hydrogen breath test and self-assessment of symptoms. This trial showed that administration of RP-G28 is effective at improving the negative symptoms of lactose digestion while remaining safe and tolerable for LI participants. Based on this study, the authors conclude that RP-G28 should continue to be clinically evaluated.
Abstract
BACKGROUND Lactose intolerance (LI) is a common medical problem with limited treatment options. The primary symptoms are abdominal pain, diarrhea, bloating, flatulence, and cramping. Limiting dairy foods to reduce symptoms contributes to low calcium intake and the risk for chronic disease. Adaptation of the colon bacteria to effectively metabolize lactose is a novel and potentially useful approach to improve lactose digestion and tolerance. RP-G28 is novel galacto-oligosaccharide (GOS) being investigated to improve lactose digestion and the symptoms of lactose intolerance in affected patients. METHODS A randomized, double-blind, parallel group, placebo-controlled study was conducted at 2 sites in the United States. RP-G28 or placebo was administered to 85 patients with LI for 35 days. Post-treatment, subjects reintroduced dairy into their daily diets and were followed for 30 additional days to evaluate lactose digestion as measured by hydrogen production and symptom improvements via a patient-reported symptom assessment instrument. RESULTS Lactose digestion and symptoms of LI trended toward improvement on RP-G28 at the end of treatment and 30 days post-treatment. A reduction in abdominal pain was also demonstrated in the study results. Fifty percent of RP-G28 subjects with abdominal pain at baseline reported no abdominal pain at the end of treatment and 30 days post treatment (p = 0.0190). RP-G28 subjects were also six times more likely to claim lactose tolerance post-treatment once dairy foods had been re-introduced into their diets (p = 0.0389). CONCLUSIONS Efficacy trends and favorable safety/tolerability findings suggest that RP-G28 appears to be a potentially useful approach for improving lactose digestion and LI symptoms. The concurrent reduction in abdominal pain and improved overall tolerance could be a meaningful benefit to lactose intolerant individuals.