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An Energy-Reduced Mediterranean Diet, Physical Activity, and Body Composition: An Interim Subgroup Analysis of the PREDIMED-Plus Randomized Clinical Trial.
Konieczna, J, Ruiz-Canela, M, Galmes-Panades, AM, Abete, I, Babio, N, Fiol, M, Martín-Sánchez, V, Estruch, R, Vidal, J, Buil-Cosiales, P, et al
JAMA network open. 2023;6(10):e2337994
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The Mediterranean diet (MedDiet), which focuses on whole grains, lean meat, fruits, vegetables, and low amounts of minimally processed foods has been shown in previous research to improve body composition and decrease fat storage around the middle. This randomised control trial of 1556 older adults aimed to determine the effects of combining a 30% lower energy version of the MedDiet in combination with physical exercise on body composition. After 3 years, the results showed that compared to a normal MedDiet without exercise, the lower energy version in combination with exercise improved body composition by decreasing total fat, and the fat stored around the organs and increasing muscle mass. However, benefits were more pronounced after 1 year and decreased slightly at 3 years. It was concluded that a low energy MedDiet in combination with physical activity may be able to improve the body composition of overweight and older adults with obesity. This study could be used by healthcare professionals to recommend a low energy MedDiet to older adults to promote weight loss, whilst attenuating muscle loss associated with ageing.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The addition of exercise to an energy-reduced diet, which focuses on whole grains, healthy fats, lean protein, and fruits and vegetables can emphasise positive effects on body composition in older adults.
- However, there is a loss of lean mass associated with this type of diet (contrary to author conclusions) and measures should be taken to monitor and increase protein intake to prevent or limit this loss.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This study aimed to determine the long-term effects of an energy reduced MedDiet in combination with physical activity on body composition.
Methods
- This is a predetermined 3-year interim analysis of a 6-year single-blind, randomised control trial of 1556 individuals aged 55-75 who are overweight or obese with metabolic syndrome.
- 760 individuals on 30% energy reduced MedDiet with limited processed foods, plus 45 minutes walking 6 days per week and behavioural and motivational support. [Intervention group]
- 761 on standard MedDiet without physical activity. [Control]
Results
Within group comparisons showed that individuals in the intervention group lost (P value represents baseline vs year 3):
- Total fat mass percentage (1-year vs baseline, −1.14%; 95% CI, −1.32% to −0.96%; 3-year vs baseline, −0.52%; 95% CI, −0.71% to −0.33% P=<0.001)
- Absolute visceral fat (1-year vs baseline, −154 g; 95% CI, −191 to −116 g; 3-year vs baseline, −75.1 g, 95% CI, −115 to −35.3 g P=<0.001)
- Absolute total fat after 1 year (mean change at 1 year vs baseline, −1677 g; 95% CI, −1930 to −1424 g) but regained some at year 3 (mean change at 3 years vs baseline, −1018 g; 95% CI, −1280 to −756 g P=<0.001)
- Absolute lean mass (mean change at 1 year vs baseline −300 g; 95% CI, −439 to −162 g) with further losses at year 3 (−626 g; 95% CI, −770 to −483 g P=0.001).
Within group comparisons also showed significantly increased:
- Total lean mass percentage, which was greater at year 1 than year 3 (1-year vs baseline, 1.07%; 95%CI, 0.90%-1.25%; 3-year vs baseline, 0.47%; 95% CI, 0.29%-0.65% P=<0.001).
As a result of total fat loss and some lean mass in the intervention group, the lean:fat mass ratio improved and was unchanged in the control group (between group differences (P=<0.001).
Compared to women, men may find the MedDiet + exercise more beneficial as it was shown that body composition changes were slightly more pronounced in men.
Conclusion
An energy-reduced MedDiet plus exercise emphasised positive changes to body composition compared to standard MedDiet in older adults who are overweight or have obesity.
Clinical practice applications:
- The recommendation of a reduced energy MedDiet in combination with physical activity to older people who are overweight or obese may improve body composition.
- Although lean mass loss slowed between years 1 and 3, other practices should be employed to attenuate the loss of lean mass associated with an energy-reduced MedDiet and ageing.
Considerations for future research:
- The research has not yet concluded but when it does, it will address the incidence of cardiovascular disease along with body composition changes.
- It will also look at long-term effects of the diet to determine longevity.
- Future research could focus on how to limit lean mass loss through the possibility of changing the type of exercise that accompanies the MedDiet.
Abstract
IMPORTANCE Strategies targeting body composition may help prevent chronic diseases in persons with excess weight, but randomized clinical trials evaluating lifestyle interventions have rarely reported effects on directly quantified body composition. OBJECTIVE To evaluate the effects of a lifestyle weight-loss intervention on changes in overall and regional body composition. DESIGN, SETTING, AND PARTICIPANTS The ongoing Prevención con Dieta Mediterránea-Plus (PREDIMED-Plus) randomized clinical trial is designed to test the effect of the intervention on cardiovascular disease prevention after 8 years of follow-up. The trial is being conducted in 23 Spanish research centers and includes men and women (age 55-75 years) with body mass index between 27 and 40 and metabolic syndrome. The trial reported herein is an interim subgroup analysis of the intermediate outcome body composition after 3-year follow-up, and data analysis was conducted from February 1 to November 30, 2022. Of 6874 total PREDIMED-Plus participants, a subsample of 1521 individuals, coming from centers with access to a dual energy x-ray absorptiometry device, underwent body composition measurements at 3 time points. INTERVENTION Participants were randomly allocated to a multifactorial intervention based on an energy-reduced Mediterranean diet (MedDiet) and increased physical activity (PA) or to a control group based on usual care, with advice to follow an ad libitum MedDiet, but no physical activity promotion. MAIN OUTCOMES AND MEASURES The outcomes (continuous) were 3-year changes in total fat and lean mass (expressed as percentages of body mass) and visceral fat (in grams), tested using multivariable linear mixed-effects models. Clinical relevance of changes in body components (dichotomous) was assessed based on 5% or more improvements in baseline values, using logistic regression. Main analyses were performed in the evaluable population (completers only) and in sensitivity analyses, multiple imputation was performed to include data of participants lost to follow-up (intention-to-treat analyses). RESULTS A total of 1521 individuals were included (mean [SD] age, 65.3 [5.0] years; 52.1% men). In comparison with the control group (n=761), participants in the intervention arm (n=760) showed greater reductions in the percentage of total fat (between group differences after 1-year, -0.94% [95% CI, -1.19 to -0.69]; 3 years, -0.38% [95% CI, -0.64 to -0.12] and visceral fat storage after 1 year, -126 g [95% CI, -179 to -73.3 g]; 3 years, -70.4 g [95% CI, -126 to -15.2 g] and greater increases in the percentage of total lean mass at 1 year, 0.88% [95% CI, 0.63%-1.12%]; 3-years 0.34% [95% CI, 0.09%-0.60%]). The intervention group was more likely to show improvements of 5% or more in baseline body components (absolute risk reduction after 1 year, 13% for total fat mass, 11% for total lean mass, and 14% for visceral fat mass; after 3-years: 6% for total fat mass, 6% for total lean mass, and 8% for visceral fat mass). The number of participants needed to treat was between 12 and 17 to attain at least 1 individual with possibly clinically meaningful improvements in body composition. CONCLUSIONS AND RELEVANCE The findings of this trial suggest a weight-loss lifestyle intervention based on an energy-reduced MedDiet and physical activity significantly reduced total and visceral fat and attenuated age-related losses of lean mass in older adults with overweight or obesity and metabolic syndrome. Continued follow-up is warranted to confirm the long-term consequences of these changes on cardiovascular clinical end points. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN89898870.
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Resistance Exercise Training Increases Muscle Mass and Strength in Prostate Cancer Patients on Androgen Deprivation Therapy.
Houben, LHP, Overkamp, M, VAN Kraaij, P, Trommelen, J, VAN Roermund, JGH, DE Vries, P, DE Laet, K, VAN DER Meer, S, Mikkelsen, UR, Verdijk, LB, et al
Medicine and science in sports and exercise. 2023;55(4):614-624
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Androgen deprivation therapy (ADT) forms the cornerstone in the treatment of localised high-risk, locally advanced, and metastatic prostate cancer (PCa). The hypothesis of this study was that protein supplementation augments the benefits of prolonged resistance exercise training to attenuate the decline in muscle mass, reduce fat mass accrual, and increase strength and physical performance in PCa patients on ADT. This study is a multicentre partly randomised controlled trial, comparing two intervention groups with a separately recruited control group. One hundred and twenty-six patients were included, and ninety-six patients finished the study. Results show that 20 week of resistance exercise training was feasible, safe, and well tolerated, and effectively counteracted the negative effect of ADT treatment on body composition, muscle mass, leg strength, and aerobic capacity in men with advanced PCa. Protein supplementation did not further augment the benefits of resistance exercise training. Authors conclude that protein supplementation is not required to further augment gains in muscle mass and strength after resistance exercise training in PCa patients who habitually consume ample protein.
Abstract
PURPOSE This study aimed to assess the effects of 20 wk resistance exercise training with or without protein supplementation on body composition, muscle mass, muscle strength, physical performance, and aerobic capacity in prostate cancer patients receiving androgen deprivation therapy (ADT). METHODS Sixty prostate cancer patients receiving ADT were randomly assigned to perform 20 wk of resistance exercise training with supplementation of 31 g whey protein (EX + PRO, n = 30) or placebo (EX + PLA, n = 30), consumed immediately after exercise and every night before sleep. A separate control group (CON, n = 36) only received usual care. At baseline and after 20 wk, body composition (dual-energy x-ray absorptiometry), muscle mass (computed tomography scan), muscle strength (1-repetition maximum strength tests), physical performance (Timed Up and Go Test, 30-Second Chair Stand Test, and Stair Climb Test), aerobic capacity (cardiopulmonary exercise test), and habitual dietary intake (food diary) were assessed. Data were analyzed using a two-factor repeated-measures ANOVA. RESULTS Over time, muscle mass and strength increased in EX + PRO and EX + PLA and decreased in CON. Total fat mass and fat percentage increased in EX + PRO and CON, but not in EX + PLA. Physical performance did not significantly change over time in either group. Aerobic capacity was maintained in EX + PLA, but it decreased in EX + PRO and CON. Habitual protein intake (without supplements) averaged >1.0 g·kg body weight -1 ·d -1 , with no differences over time or between groups. CONCLUSIONS In prostate cancer patients, resistance exercise training counteracts the adverse effects of ADT on body composition, muscle mass, muscle strength, and aerobic capacity, with no additional benefits of protein supplementation.
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The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial.
Zelicha, H, Kloting, N, Kaplan, A, Yaskolka Meir, A, Rinott, E, Tsaban, G, Chassidim, Y, Bluher, M, Ceglarek, U, Isermann, B, et al
BMC medicine. 2022;20(1):327
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Visceral adipose tissue (VAT) accumulation is one of the main key factors that differentiate between metabolic healthy and unhealthy obese individuals. VAT is closely related to the development of multiple cardiovascular risk factors. The Mediterranean (MED) diet, high in polyphenol content and rich in plant food sources, was shown to have an enhanced effect on VAT reduction in combination with physical activity (PA), regardless of weight loss The aim of this study was to assess the effect of the MED diet, further enriched with polyphenols, and lower in red and processed meat (“green-MED diet”) on visceral adiposity in the 18-month Dietary Intervention Randomized Controlled Trial-Polyphenols, Unprocessed trial. This study is a randomised controlled trial. Participants were randomly assigned to one of three intervention groups (1:1:1 ratio): healthy dietary guidelines, MED diet, or green-MED diet, all included PA recommendations, with a free gym membership and educational sessions promoting moderate-intensity PA. Results show that participants following the green-MED diet achieved more than twice the degree of VAT reduction compared to those following the MED diet, despite similar weight loss. In fact, VAT loss was specifically related to lower red meat intake and increased walnuts, green tea, Wolfa globosa, and dietary fibre (this was reflected by higher plasma polyphenol and serum folate levels). Authors conclude that a green-MED diet enriched with polyphenols and decreased red meat consumption might serve as an improved version of the MED diet for targeted VAT reduction.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The positive health effects of the traditional MED diet, moderately high in PUFAs and MUFAs and low in red meat, are well-established
- Higher levels of total plasma polyphenol and serum folate may reflect higher consumption of “green” dietary components, which were significantly associated with greater VAT loss
- The green-MED diet, richer in dietary polyphenols and green plant-based proteins and lower in red meat, might be a more effective strategy for VAT loss than the traditional healthy MED diet, achieving more than twice the degree of VAT reduction, despite similar weight loss.
- VAT loss was specifically related to lower red meat intake and increased walnuts, green tea, Wolffia globosa, and dietary fibre and was reflected by higher plasma polyphenol and serum folate levels.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
A mediterranean (MED) diet is a rich source of polyphenols, which benefit adiposity by several mechanisms. Visceral adipose tissue (VAT) accumulation is one of the main factors that differentiate between metabolic healthy and unhealthy obese individuals.
In this Dietary Intervention Randomised Controlled Trial PoLyphenols UnproceSsed (DIRECT‐ PLUS) weight‐loss trial, 294 participants were randomised to: (A) healthy dietary guidelines (HDG), (B) MED, or (C) green‐MED diets, all combined with physical activity. The study duration was 18‐months.
This study explored the effect of the green‐MED diet, twice fortified in dietary polyphenols and lower in red/processed meat, on visceral adipose tissue (VAT) and used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues.
Both isocaloric (with the same calorific value) MED groups consumed 28 g/day of walnuts (+ 440 mg/day polyphenols). The green‐MED group further consumed green tea (3–4 cups/day) and Wolffia globosa (duckweed strain) plant green shake (100 g frozen cubes/day) (+ 800mg/day polyphenols) and reduced red meat intake.
The mean weight loss (HDG: −0.4% (5.0), MED: −2.7% (5.6), green-MED: −3.9% (6.5)) and WC loss (HDG: −3.6% (5.1), MED: −4.7% (5.0), green-MED: −5.7%(5.7)) after 18 months were similar between the two MED diets (p > 0.05 for all) and higher as compared to the HDG (weight: HDG vs. MED: p = 0.02; HDG vs. green+MED: p < 0.001; WC: HDG vs. MED: p = 0.33, HDG vs. green+MED: p = 0.02).
All three abdominal fat depots decreased over 18 months of intervention (p < 0.05 vs. baseline for all). The green-MED group achieved a greater reduction in VAT than the other intervention groups (HDG: −4.2% (22.5), MED: −6.0%(31.3), green-MED: −14.1%(27.7); p < 0.05 green-MED vs. MED or vs. HDG groups). These differences in VAT loss across the groups remained significant after adjusting for age, sex, and 18-month WC change (green-MED vs. MED p = 0.023; green-MED vs. HDG p = 0.002) (Fig. 1)
Limitations of the study included a low proportion of women, and different VAT proportions at baseline across groups limit the generalisability of findings to women.
The authors of the study did not identify the exact components responsible for the dietary effects when they compared dietary regimens and not specific nutrients.
Adherence was by a validated, self-reported dietary intake assessment tool, which the authors acknowledge is subject to error
Strengths of the study included the relatively large sample size, high retention rate, and use of 3-T MRI measurements (considered one of the gold standards tools for the quantification of specific fat depots
Clinical practice applications:
- This trial shows that, when combined with a Mediterranean diet, higher dietary consumption of green tea, walnuts, and dietary fibre and reduced red meat consumption were significantly associated with greater %VAT loss
- The authors observed a significant synergistic interaction effect between decreased red meat consumption and increased serum folate on VAT loss
- A reduction in VAT accumulation, known as a key risk factor in CVD development, may reduce metabolic complications, improve the lipid profile, and decrease cardiometabolic risk.
Considerations for future research:
- Future studies are needed to explore the exact mechanisms of specific polyphenol-rich foods on visceral adiposity.
- Future studies could explore whether the results are replicable in both male and female participants, as this sample was largely male.
Abstract
BACKGROUND Mediterranean (MED) diet is a rich source of polyphenols, which benefit adiposity by several mechanisms. We explored the effect of the green-MED diet, twice fortified in dietary polyphenols and lower in red/processed meat, on visceral adipose tissue (VAT). METHODS In the 18-month Dietary Intervention Randomized Controlled Trial PoLyphenols UnproceSsed (DIRECT-PLUS) weight-loss trial, 294 participants were randomized to (A) healthy dietary guidelines (HDG), (B) MED, or (C) green-MED diets, all combined with physical activity. Both isocaloric MED groups consumed 28 g/day of walnuts (+ 440 mg/day polyphenols). The green-MED group further consumed green tea (3-4 cups/day) and Wolffia globosa (duckweed strain) plant green shake (100 g frozen cubes/day) (+ 800mg/day polyphenols) and reduced red meat intake. We used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues. RESULTS Participants (age = 51 years; 88% men; body mass index = 31.2 kg/m2; 29% VAT) had an 89.8% retention rate and 79.3% completed eligible MRIs. While both MED diets reached similar moderate weight (MED: - 2.7%, green-MED: - 3.9%) and waist circumference (MED: - 4.7%, green-MED: - 5.7%) loss, the green-MED dieters doubled the VAT loss (HDG: - 4.2%, MED: - 6.0%, green-MED: - 14.1%; p < 0.05, independent of age, sex, waist circumference, or weight loss). Higher dietary consumption of green tea, walnuts, and Wolffia globosa; lower red meat intake; higher total plasma polyphenols (mainly hippuric acid), and elevated urine urolithin A polyphenol were significantly related to greater VAT loss (p < 0.05, multivariate models). CONCLUSIONS A green-MED diet, enriched with plant-based polyphenols and lower in red/processed meat, may be a potent intervention to promote visceral adiposity regression. TRIAL REGISTRATION ClinicalTrials.gov , NCT03020186.
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Oxidative Stress and Inflammation Are Associated With Age-Related Endothelial Dysfunction in Men With Low Testosterone.
Babcock, MC, DuBose, LE, Witten, TL, Stauffer, BL, Hildreth, KL, Schwartz, RS, Kohrt, WM, Moreau, KL
The Journal of clinical endocrinology and metabolism. 2022;107(2):e500-e514
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Serum testosterone declines gradually with age at a rate of ~1% per year after the third decade. Vascular aging, featuring endothelial dysfunction mediated by oxidative stress and inflammation, is a major risk factor for the development of age-associated cardiovascular disease (CVD). The aim of this study was to examine the effects of low testosterone on cardiovascular aging in men. This study is a cross-sectional study which recruited 58 healthy men of all races/ethnic backgrounds aged 50-75 years (middle-aged/older) and 18-40 years (young). Results show that middle-aged/older men with lower testosterone have evidence of “accelerated” vascular aging, as indicated by a greater age-associated endothelial dysfunction of large arteries compared with their age-matched peers. The greater macrovascular endothelial dysfunction in middle-aged/older men with chronically low testosterone was independent of CVD risk factors or symptoms of androgen deficiency. Furthermore, increased systemic oxidative stress and inflammation are mechanistically linked to the greater age-associated endothelial dysfunction in middle-aged/older men with lower testosterone. Authors conclude that normal physiological levels of testosterone may be beneficial to cardiovascular health by attenuating the age-related decline in endothelial function.
Abstract
CONTEXT Vascular aging, including endothelial dysfunction secondary to oxidative stress and inflammation, increases the risk for age-associated cardiovascular disease (CVD). Low testosterone in middle-aged/older men is associated with increased CVD risk. OBJECTIVE We hypothesized that low testosterone contributes to age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation. METHODS This cross-sectional study included 58 healthy, nonsmoking men categorized as young (N = 20; age 29 ± 4 years; testosterone 500 ± 58 ng/dL), middle-aged/older with higher testosterone (N = 20; age 60 ± 6 years; testosterone 512 ± 115 ng/dL), and middle-aged/older lower testosterone (N = 18; age 59 ± 8 years; testosterone 269 ± 48 ng/dL). Brachial artery flow-mediated dilation (FMDBA) was measured during acute infusion of saline (control) and vitamin C (antioxidant). Markers of oxidative stress (total antioxidant status and oxidized low-density lipoprotein cholesterol), inflammation (interleukin [IL]-6 and C-reactive protein [CRP]), and androgen deficiency symptoms were also examined. RESULTS During saline, FMDBA was reduced in middle-aged/older compared with young, regardless of testosterone status (P < 0.001). FMDBA was reduced in middle-aged/older lower testosterone (3.7% ± 2.0%) compared with middle-aged/older higher testosterone (5.7% ± 2.2%; P = 0.021), independent of symptoms. Vitamin C increased FMDBA (to 5.3% ± 1.6%; P = 0.022) in middle-aged/older lower testosterone but had no effect in young (P = 0.992) or middle-aged/older higher testosterone (P = 0.250). FMDBA correlated with serum testosterone (r = 0.45; P < 0.001), IL-6 (r = -0.41; P = 0.002), and CRP (r = -0.28; P = 0.041). CONCLUSION Healthy middle-aged/older men with low testosterone appear to have greater age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation. These data suggest that low testosterone concentrations may contribute to accelerated vascular aging in men.
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Intramyocellular Lipids, Insulin Resistance, and Functional Performance in Patients with Severe Obstructive Sleep Apnea.
Chien, MY, Lee, PL, Yu, CW, Wei, SY, Shih, TT
Nature and science of sleep. 2020;12:69-78
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Obstructive sleep apnoea syndrome (OSA) is characterized by repeated occlusion of the upper airway during sleep, resulting in periods of intermittent hypoxemia [low level of oxygen in blood]. The aim of this study was to (a) investigate the intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL), biochemical data, and functional performance in patients with severe OSA versus controls, and (b) examine the correlations between intra-muscular lipid contents and biochemical and performance variables. This study is a clinical trial that recruited 20 patients with OSA and body mass index(BMI)-matched controls. Results demonstrate that patients with OSA had significantly lower IMCL and EMCL values when compared with their age-, and BMI-matched controls without OSA. Furthermore, compared with controls, patients with OSA had significantly reduced functional performance and exhibited abnormal biochemical data, including glucose and insulin levels and lipid profiles. Authors conclude that additional large-scale clinical trials are required to further explore the complex mechanism between OSA, muscle metabolism, and insulin action.
Abstract
PURPOSE An increasing number of studies have linked the severity of obstructive sleep apnea (OSA) with metabolic dysfunction. However, little is known about the lipid compartments (intramyocellular [IMCL] and extramyocellular [EMCL] lipids) inside the musculature in these patients. The present study was designed to investigate the IMCL and EMCL, biochemical data, and functional performance in patients with severe OSA, and to examine the correlations between intramuscular lipid contents and test variables. PARTICIPANTS AND METHODS Twenty patients with severe OSA (apnea-hypopnea index [AHI]: ≥30/h; body mass index [BMI]: 26.05±2.92) and 20 age- and BMI-matched controls (AHI <5/h) were enrolled. Proton magnetic resonance spectroscopy was used to measure the IMCL and EMCL of the right vastus lateralis muscle. Biochemical data, including levels of fasting plasma glucose, insulin, lipid profiles, and high-sensitivity C-reactive protein (hsCRP), were measured. Insulin resistance index (IR) was calculated using the homeostasis model assessment method. Performance tests included a cardiopulmonary exercise test and knee extension strength and endurance measurements. RESULTS Patients with severe OSA had significantly (P<0.05) lower values of IMCL (14.1±5.4 AU) and EMCL (10.3±5.8 AU) compared to the control group (25.2±17.6 AU and 14.3±11.1 AU, respectively). Patients with severe OSA had significantly higher hsCRP, IR, and dyslipidemia compared with controls (all P<0.05). Furthermore, IMCL was negatively correlated with AHI, cumulative time with nocturnal pulse oximetric saturation lower than 90% (TSpO2<90%) (ρ=-0.35, P<0.05), IR (ρ=-0.40, P<0.05), glucose (ρ=-0.33, P<0.05), and insulin (ρ=-0.36, P<0.05), and positively correlated with lowest oximetric saturation (ρ=0.33, P<0.01). CONCLUSION Skeletal muscle dysfunction and metabolic abnormalities were observed in patients with OSA that did not have obesity. IMCL was positively correlated with aerobic capacity and muscular performance, but negatively correlated with AHI and IR. Large-scale clinical trials are required to explore the complicated mechanism among OSA, intramuscular metabolism, and insulin action. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT00813852.
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Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial.
Kahleova, H, Petersen, KF, Shulman, GI, Alwarith, J, Rembert, E, Tura, A, Hill, M, Holubkov, R, Barnard, ND
JAMA network open. 2020;3(11):e2025454
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Obesity is uncommon in individuals on a plant-based diet, possibly due to the high-fiber low fat nature of this style of eating and due to the fact that low levels of fat may increase metabolism levels. The aim of this randomised control trial of 244 people following a vegan diet was to assess the effects of a low-fat vegan diet on body weight, insulin resistance (IR), metabolism and lipid levels in the liver and muscle over 16 weeks. The results showed that individuals who followed the low-fat vegan diet as opposed to a normal vegan diet lost more weight, attributed to a loss of body fat and had decreased cholesterol levels. Measures of how the body balances blood sugars were improved and this was directly related to weight loss. The amount of energy needed to digest the food in the intervention diet was increased compared to the control group and this was involved in a relationship whereby as fat mass decreased, blood sugar balance improved, and metabolism increased. Liver lipids decreased in the intervention group, which was directly related to body weight loss and as liver lipids decreased, blood sugar balance increased. Muscle lipids were significantly decreased in the intervention group compared to the control group. It was shown that as fat mass decreased, muscle fat levels and blood sugar balance improved. It was concluded that the low-fat plant-based diet reduced body weight due to a reduced energy intake and increased body metabolism following eating. Blood sugar control was improved due to reduced fat levels in the muscles and liver. This study could be used by healthcare professionals to recommend a low-fat plant based diet to individuals who are overweight and/or who are showing signs of blood sugar imbalance.
Abstract
Importance: Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions. Objective: To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults. Design, Setting, and Participants: This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone. Interventions: Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks. Main Outcomes and Measures: At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis. Results: Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (-1.3; 95% CI, -2.2 to -0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = -0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01). Conclusions and Relevance: A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity. Trial Registration: ClinicalTrials.gov Identifier: NCT02939638.
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Adherence to the Mediterranean Diet and Its Association with Body Composition and Physical Fitness in Spanish University Students.
Cobo-Cuenca, AI, Garrido-Miguel, M, Soriano-Cano, A, Ferri-Morales, A, Martínez-Vizcaíno, V, Martín-Espinosa, NM
Nutrients. 2019;11(11)
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The Mediterranean diet (MD) represents a dietary pattern that incorporates healthy traditional eating habits which includes high consumption of vegetables, fruit, legumes, nuts, beans, whole grains, fish, and unsaturated fats, and low consumption of red meat and dairy products. The Mediterranean Diet Adherence Screener (MEDAS-14 items) is a valid instrument for the estimation of adherence to the MD. The objectives of this study were to: 1. Estimate the prevalence of the adherence to the MD 2. Assess the association of adherence to the MD with physical fitness and body composition 3. Know the ability of each MEDAS item in the same sample to predict MD adherence. This study is a cross-sectional observational study which was performed with 310 first-year Spanish university students, aged between 18 and 30 years. Results indicate low prevalence of good adherence to the MD; and the participants with good adherence had high protein and low-fat intake compared to those with medium to low adherence. Furthermore, higher levels of physical fitness were also noticed amongst participants with good adherence to the MD. Twelve of the 14 items of the MEDAS score were associated with a high adherence to the MD. Authors conclude that MD adherence benefits both cardiorespiratory and muscular fitness amongst young adults.
Abstract
The aims of this study were to assess the association of adherence to the Mediterranean diet (MD) with physical fitness and body composition in Spanish university students and to determine the ability to predict the MD adherence of each Mediterranean Diet Adherence Screener (MEDAS) item. A cross-sectional study was performed involving 310 first-year university students. Adherence to the MD was evaluated with MEDAS-14 items. Anthropometric variables, body composition, and physical fitness were assessed. Muscle strength was determined based on handgrip strength and the standing long jump test. Cardiorespiratory fitness (CRF) was measured using the Course-Navette test. Only 24% of the university students had good adherence to the MD. The ANCOVA models showed a significant difference between participants with high adherence to the MD and those with medium and low adherence in CRF (p = 0.017) and dynamometry (p = 0.005). Logistic binary regression showed that consuming >2 vegetables/day (OR = 20.1; CI: 10.1-30.1; p < 0.001), using olive oil (OR = 10.6; CI: 1.4-19.8; p = 0.021), consuming <3 commercial sweets/week (OR = 10.1; IC: 5.1-19.7; p < 0.001), and consuming ≥3 fruits/day (OR = 8.8; CI: 4.9-15.7; p < 0.001) were the items most associated with high adherence to the MD. In conclusion, a high level of adherence to the MD is associated with high-level muscular fitness and CRF in Spanish university students.
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An Increase in Fat Mass Index Predicts a Deterioration of Running Speed.
Genton, L, Mareschal, J, Karsegard, VL, Achamrah, N, Delsoglio, M, Pichard, C, Graf, C, Herrmann, FR
Nutrients. 2019;11(3)
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Registration to recreational runs is likely used by many participants as a motivational tool for regular endurance training in order to improve health-related physical fitness. The study aims to evaluate (1) the impact of body composition changes on the evolution of running speed (2) the effects of ageing on this aforementioned relationship and (3) the influence of baseline body composition on the evolution of running speed. The study is a longitudinal cohort study that included people >16 years who ran in a timed city run. The study population included 377 women and 509 men. Results indicate that running speed over 5km in women and 7km in men increased as fat mass index (is a measure of relative fat content), and, to a lesser extent, body mass index decreased. The impact of fat-free mass index (is an alternative to body mass index which accounts for a person's muscle mass) was gender-specific. The study highlights the importance of following body composition in ambitious recreational runners who want to maintain their performance as long as possible.
Abstract
A low fat mass is associated with a good running performance. This study explores whether modifications in body composition predicted changes in running speed. We included people who underwent several measurements of body composition by bioelectrical impedance analysis between 1999 and 2016, at the "Course de l'Escalade", taking place yearly in Geneva. Body composition was reported as a fat-free mass index (FFMI) and fat mass index (FMI). Running distances (men: 7.2 km; women: 4.8 km) and running times were used to calculate speed in km/h. We performed multivariate linear mixed regression models to determine whether modifications of body mass index, FFMI, FMI or the combination of FFMI and FMI predicted changes in running speed. The study population included 377 women (1419 observations) and 509 men (2161 observations). Changes in running speed were best predicted by the combination of FFMI and FMI. Running speed improved with a reduction of FMI in both sexes (women: ß -0.31; 95% CI -0.35 to -0.27, p < 0.001. men: ß -0.43; 95% CI -0.48 to -0.39, p < 0.001) and a reduction of FFMI in men (ß -0.20; 95% CI -0.26 to -0.15, p < 0.001). Adjusted for body composition, the decline in running performance occurred from 50 years onward, but appeared earlier with a body mass, FFMI or FMI above the median value at baseline. Changes of running speed are determined mostly by changes in FMI. The decline in running performance occurs from 50 years onward but appears earlier in people with a high body mass index, FFMI or FMI at baseline.
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Role of Calcium and Low-Fat Dairy Foods in Weight-Loss Outcomes Revisited: Results from the Randomized Trial of Effects on Bone and Body Composition in Overweight/Obese Postmenopausal Women.
Ilich, JZ, Kelly, OJ, Liu, PY, Shin, H, Kim, Y, Chi, Y, Wickrama, KKAS, Colic-Baric, I
Nutrients. 2019;11(5)
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A woman’s menopausal years are believed to bring about weight gain due to various biological mechanisms, such as depletion of oestrogen. Many women undertake weight loss diets, in an attempt to control the weight gain, and although weight loss can reduce the risk factors for metabolic and cardiovascular disease etc, it can also lead to accelerated loss bone density and muscle mass. The objective of this study was to investigate whether by complementing a low-calorie diet with 4 to 5 servings of low-fat dairy foods per day and/or supplementing with calcium and vitamin D supplements would aid weight loss and preserve either/both bone and muscle mass. The study was conducted on 189 early postmenopausal, obese women. It was a randomized, placebo-controlled clinical trial conducted over 6 months. Researchers found that results were better for the participants on the low-fat dairy foods and those supplementing with calcium and vitamin D when compared to the placebo group (who only had placebo pills). They suggest that when embarking on a weight loss program it is beneficial to include 4 to 5 servings of low-fat dairy foods each day and take calcium and vitamin D supplements will have a positive impact on weight loss, bone density and muscle mass in post-menopausal women.
Abstract
Several studies have investigated the possibility of dairy foods and calcium (Ca) mediating weight and body composition, but a consensus has not been reached. We aimed to investigate weight-loss-related outcomes during intervention with low-fat dairy foods or Ca + vitamin D supplements, both as complements to hypocaloric diets. Overweight/obese Caucasian, early-postmenopausal women (n = 135) were recruited for a 6 month energy-restricted weight loss study complemented with either low-fat dairy foods (D; 4-5 servings/day), or Ca + vitamin D supplements (S); both to amount a total of ~1500 mg/day and 600 IU/day of Ca and vitamin D, respectively, or placebo pills (C). Bone mineral density (BMD) and lean and fat tissue were measured by Lunar iDXA. Serum and urinary markers of bone turnover were analyzed. Diet and physical activity were assessed with 3-day records. Participants on average lost ~4%, ~3%, and ~2% of body weight, fat, and lean tissue, respectively. The significantly better outcomes were noticed in participants in the D group regarding body composition (fat loss/lean tissue preservation) and in participants in the S group regarding the BMD outcomes, compared to those in the C group. Therefore, increasing low-fat dairy foods to 4-5 servings/day and/or increasing Ca & vitamin D intake by supplements (in those who are at the borderline dietary intake) may be beneficial for weight loss/maintenance and may lead to more favorable bone and body composition outcomes in postmenopausal women during moderate weight loss.
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Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men.
Kirmse, M, Oertzen-Hagemann, V, de Marées, M, Bloch, W, Platen, P
Nutrients. 2019;11(5)
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Currently little is known concerning collagen protein supplementation combined with a prolonged resistance exercising training (RET) programme. The aim of this study was to determine the effects of long-term collagen peptide supplementation and RET on body composition, strength and muscle fibre cross-sectional surface area (fCSA) in 57 recreationally active men. In this double-blind, placebo-controlled study, participants were randomly allocated to receive either collagen peptides or placebo for 12 weeks. Both groups trained three times a week. Strength testing, bioimedance analysis and muscle biopsies were taken at baseline and post-intervention. Most notably the collagen group experienced a significant increase in fat-free mass while body fat mass remained unchanged, compared to the placebo group. Both groups showed significant increases in strength tests and the fCSA increased significantly without differences. Based on these results, the authors conclude collagen protein supplementation have positive impact on body composition however suggest further study include connective tissue in addition to muscle tissue to better understand the mechanisms underlying these changes.
Abstract
We aimed to determine the effects of long-term collagen peptide (CP) supplementation and resistance exercise training (RET) on body composition, strength, and muscle fiber cross-sectional area (fCSA) in recreationally active men. Fifty-seven young men were randomly and double-blinded divided into a group receiving either collagen peptides (COL, 15 g/day) or a placebo (PLA). Strength testing, bioimpedance analysis, and muscle biopsies were used prior to and after an RET intervention. Food record protocols were performed during the RET intervention. The groups trained three times a week for 12 weeks. Baseline parameters showed no differences between groups, and the external training load and dietary food intake were also similar. COL showed a significant increase in fat-free mass (FFM) compared with the placebo group (p < 0.05). Body fat mass (BFM) was unchanged in COL, whereas a significant increase in BFM was observed in PLA. Both groups showed significant increases in all strength tests, with a trend for a slightly more pronounced effect in COL. The fCSA of type II muscle fibers increased significantly in both groups without differences between the two groups. We firstly demonstrated improved body composition in healthy, recreationally active men subsequent to prolonged CP supplementation in combination with RET. As the observed increase in FFM was not reflected in differences in fCSA hypertrophy between groups, we assume enhanced passive connective tissue adaptations in COL due to CP intake.