Vegan Diet, Sarcopenia, Cardiovascular Health, Osteoporosis, Gut Health
Conditions
Brief summary
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.
Interventions
OTHERVegan diet
A self-composed 12 week fully plant-based diet
OTHERResistance exercise
Biweekly resistance exercise for 12 weeks
OTHEROmnivorous diet
Habitual diet containing both animal- and plant-based food products
Sponsors
Wageningen University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
65 Years to No maximum
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in thigh muscle volume | 12 weeks | Thigh muscle volume of both legs will be assessed using magnetic resonance imaging before and after the 3-month intervention |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Body composition | Change after 12 weeks | 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. |
| Change in muscle strength | Change after 12 weeks | Maximal isometric knee extension and flexion strength of both legs will be measured using Biodex. |
| Muscle fractional synthesis rates | 10 days | 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. |
| Change in bone mineral density | Change after 12 weeks | Measured using a Dual X-Ray Absorptiometry dual femur scan |
| Change in fasting bone turnover markers | Change after 6 and 12 weeks | 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. |
| Change in plasma insulin growth factor 1 levels | Change after 6 and 12 weeks | Fasting serum insulin-like growth factor 1 (IGF-1) |
| Change in plasma parathyroid hormone (PTH) levels | Change after 6 and 12 weeks | Fasting plasma PTH |
| Change in fasting plasma insulin levels | Change after 6 and 12 weeks | Fasting plasma insulin |
| Change in metabolic profile | Change after 6 and 12 weeks | Fasting plasma levels of multiple metabolites |
| Change in fasting blood pressure | Change after 6 and 12 weeks | Fasting systolic and diastolic blood pressure |
| Change in haemoglobin levels | Change after 12 weeks | Fasting plasma haemoglobin levels |
| Change in vitamin D status | Change after 12 weeks | Fasting serum vitamin D levels |
| Change in gastro-intestinal symptoms | Change after 12 weeks | 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. |
| Untargeted gut metabolomics | Change after 12 weeks | Untargeted gut metabolomics will be performed on fasting plasma samples |
| Change in fasting plasma high-sensitive C-reactive protein (hs-CRP) | Change after 6 and 12 weeks | Fasting plasma hs-CRP |
| Change in ferritin levels | Change after 12 weeks | Fasting plasma ferritin levels |
| Tryptophan | Change after 12 weeks | Tryptophan will be assessed using targeted metabolomics on plasma samples |
| Tyrosine | Change after 12 weeks | Tyrosine will be assessed using targeted metabolomics on plasma samples |
| Branch-chained amino acids | Change after 12 weeks | Branch-chained amino acids will be assessed using targeted metabolomics on plasma samples |
| Oxidized amino acids | Change after 12 weeks | Oxidized amino acids will be assessed using targeted metabolomics on plasma samples |
| Gut metagenomics | Change after 12 weeks | 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. |
| Change in vitamin B12 status | Change after 12 weeks | Fasting plasma methylmalonic acid levels |
Other
| Measure | Time frame | Description |
|---|---|---|
| Change in body weight | Change after 10 days and after 12 weeks | Body weight (kg) will be measured in a fasted state using a calibrated digital scale |
Countries
Netherlands
Outcome results
None listed