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

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.