The Effect of a 12-week Self-composed Vegan Diet With or Without Concurrent Resistance Exercise on Thigh Muscle Volume in Older Adults

Wageningen University72 enrolled

Overview

Consumers are increasingly encouraged to consume more plant-based foods and lower their consumption of foods from animal origin. This shift is driven by environmental and health factors. However, the consequences of such a transition on muscle mass still remains to be explored. This is of particular importance in the older population, where the age-related reduction in muscle mass and strength is highly prevalent. Adequate dietary intake, specifically protein intake, is a well-known strategy in promoting muscle mass in older adults. Plant-based foods are currently considered to be inferior to animal-based foods in their protein quality, and are therefore considered to be suboptimal for the maintenance of muscle mass at an older age. On the other hand, combining plant-based foods may improve the protein quality and thereby the anabolic properties of a vegan meal. Evidence regarding the anabolic properties of vegan diets in older adults is scarce. As such, the current study aims to assess 1) the effects of a 12-week self-composed vegan diet in comparison to an omnivorous diet on thigh muscle volume (TMV) in community-dwelling older adults and 2) the effect of a 12-week self-composed vegan diet combined with twice-weekly resistance exercise (RE) on TMV in comparison to a self-composed vegan diet without resistance exercise in community-dwelling older adults.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Enrollment

Conditions

Vegan Diet

Eligibility

Sex: ALLMin age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Aged ≥65 years old; * Community-dwelling; * BMI 23-32 kg/m2; * Habitual diet contains animal-based food products (i.e. dairy, meat and/or fish) at least 5 days per week; Exclusion Criteria: * Following a self-reported entirely vegetarian or vegan diet during the six months prior to the study; * Following a prescribed high (≥1.2 g/kg/d) or low protein diet (\<0.8 g/kg/d), and/or or taking protein supplements on medical advice, during the month prior to the study; * Participating in a structured progressive resistance exercise training program the during three months prior to the study; * ≥4 kg of body weight loss during three months before the start of the study; * Being diagnosed with one of the following: diabetes mellitus; renal disease; neurological or neuromuscular disorders; serious cardiovascular diseases; cancer (with the exception of the following types of skin cancer: basal cell carcinoma, squamous cell carcinoma); (very) severe chronic obstructive lung disease (COPD; GOLD stage III or IV); bowel disease. * Chronic use of medication that affects muscle function as assessed by the research physician; * The use of anticoagulants incompatible for muscle biopsies as assessed by the research physician: acenocoumarol (sintrom); phenprocoumon (marcoumar); dabigatran (pradaxa); apixaban (eliquis); rivaroxaban (xarelto); clopidogrel (plavix); edoxaban (lixiana); combination of acetylsalicylic acid or carbasalate calcium (ascal) with dipyridamole; * Having a contra-indication to MRI scanning (including, but not limited to): * Pacemakers and defibrillators * Infraorbital or intraocular metallic fragments * Ferromagnetic implants * Claustrophobia * Having a hip prosthesis * Not willing to stop nutritional supplements, with the exception of supplements on medical advice, and vitamin D; * Not willing or afraid to give blood, undergo a muscle biopsy or have an MRI scan during the study; * Unwilling to eat a self-composed vegan diet or an omnivorous diet with daily consumption of animal-based food sources for 3 months; * Unwilling to participate in RE twice a week for 3 months; * Currently a research participant in another trial or participated in a clinical trial during one month before the start of the measurement period; * Not being able to understand Dutch; * Not having a general physician; * Working, or having a direct family member that work at the Division of Human Nutrition at Wageningen University during the study. * Unwilling to be informed about incidental findings of pathology and approving of reporting this to their general physician.

Outcomes

Primary Outcomes

Change in thigh muscle volume

Thigh muscle volume of both legs will be assessed using magnetic resonance imaging before and after the 3-month intervention

Time frame: 12 weeks

Secondary Outcomes

Body composition

Other body composition indices will also be measured using magnetic resonance imaging before and after the intervention. These indices include: liver fat fraction, thigh muscle fat infiltration, abdominal subcutaneous adipose tissue, visceral fat tissue.

Time frame: Change after 12 weeks

Change in muscle strength

Maximal isometric knee extension and flexion strength of both legs will be measured using Biodex.

Time frame: Change after 12 weeks

Muscle fractional synthesis rates

Muscle fractional synthesis rates, expressed as daily fractional synthesis rates (FSR, %/day), will be assessed using a deuterium oxide protocol. Daily FSR will be calculated using the 2\^H-alanine enrichment in plasma and the mixed muscle-bound 2\^H-alanine enrichment.

Time frame: 10 days

Change in bone mineral density

Measured using a Dual X-Ray Absorptiometry dual femur scan

Time frame: Change after 12 weeks

Change in fasting bone turnover markers

Serum procollagen type I N-terminal propeptide (P1NP) will be measured for bone formation and C-terminal telopeptide of type I collagen (CTX) for bone resorption.

Time frame: Change after 6 and 12 weeks

Change in plasma insulin growth factor 1 levels

Fasting serum insulin-like growth factor 1 (IGF-1)

Time frame: Change after 6 and 12 weeks

Change in plasma parathyroid hormone (PTH) levels

Fasting plasma PTH

Time frame: Change after 6 and 12 weeks

Change in fasting plasma insulin levels

Fasting plasma insulin

Time frame: Change after 6 and 12 weeks

Change in metabolic profile

Fasting plasma levels of multiple metabolites

Time frame: Change after 6 and 12 weeks

Change in fasting blood pressure

Fasting systolic and diastolic blood pressure

Time frame: Change after 6 and 12 weeks

Change in haemoglobin levels

Fasting plasma haemoglobin levels

Time frame: Change after 12 weeks

Change in vitamin B12 status

Fasting plasma methylmalonic acid levels

Time frame: Change after 12 weeks

Change in vitamin D status

Fasting serum vitamin D levels

Time frame: Change after 12 weeks

Change in gastro-intestinal symptoms

Self-reported gastro-intestinal symptoms using the gastro-intestinal symptom rating scale. The questionnaire includes 15 questions covering 5 common symptom clusters on a 7-point likert scale ranging from no symptoms (minimum) to severe symptoms (maximum). A higher score indicates worse symptoms.

Time frame: Change after 12 weeks

Untargeted gut metabolomics

Untargeted gut metabolomics will be performed on fasting plasma samples

Time frame: Change after 12 weeks

Change in fasting plasma high-sensitive C-reactive protein (hs-CRP)

Fasting plasma hs-CRP

Time frame: Change after 6 and 12 weeks

Change in ferritin levels

Fasting plasma ferritin levels

Time frame: Change after 12 weeks

Tryptophan

Tryptophan will be assessed using targeted metabolomics on plasma samples

Time frame: Change after 12 weeks

Tyrosine

Tyrosine will be assessed using targeted metabolomics on plasma samples

Time frame: Change after 12 weeks

Branch-chained amino acids

Branch-chained amino acids will be assessed using targeted metabolomics on plasma samples

Time frame: Change after 12 weeks

Oxidized amino acids

Oxidized amino acids will be assessed using targeted metabolomics on plasma samples

Time frame: Change after 12 weeks

Gut metagenomics

Microbial DNA will be isolated from the feces samples. The taxonomy and function of specific genes will be assessed via metagenomic sequencing on the microbial DNA.

Time frame: Change after 12 weeks

The Effect of a 12-week Self-composed Vegan Diet With or Without Concurrent Resistance Exercise on Thigh Muscle Volume in Older Adults

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes